Changes in nerves and neuropeptides in skin from 100 leprosy patients investigated by immunocytochemistry

The cutaneous innervation is now known to contain neuropeptides including substance P (SP) and calcitonin gene-related peptide (CGRP) in sensory nerves, and vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY), principally in autonomic nerves. Skin biopsies from 100 leprosy patients and equivalent areas from 50 non-leprosy controls were fixed in p-benzoquinone solution for immunofluorescence staining and in Bouin's fluid for classification of leprosy type. Antisera to the neural markers, neurofilaments, and protein gene product 9.5 (PGP 9.5), and to neuropeptides were used. Cutaneous nerves and nerve endings immunoreactive for neuropeptides, neurofilaments, and PGP 9.5 were seen in all non-leprous control cases. In leprosy, PGP 9.5- and neurofilament-immunoreactive nerve fibres were seen in all 14 cases of the indeterminate (early) type and in the majority (33/43) of lepromatous cases, but in a smaller proportion (15/43) of tuberculoid cases. Neuropeptide immunoreactivity was seen in only 2/14 of the indeterminate leprosy specimens and was completely absent in other types. This early disappearance may be of diagnostic significance. Thus, cutaneous sensory and autonomic dysfunctions in leprosy are well reflected by changes in nerve fibres and neuropeptides.     

Blood vessels in liver metastases from both sarcoma and carcinoma lack perivascular innervation and smooth muscle cells.

Hepatic arterial infusion (HAI) chemotherapy as treatment for human colorectal liver metastases is promising, but not entirely satisfactory. Improved drug delivery during HAI may be achieved by manipulating the different control mechanisms of normal versus tumour blood vessels. The peptidergic/aminergic innervation of vessels in normal liver and in two animal models of liver metastasis (Lister Hooded rat with syngeneic MC28 sarcoma; athymic (nude) rat with human HT29 carcinoma) was investigated to assess the suitability of these models for future pharmacological studies. Normal liver and metastases were studied immunohistochemically for the presence of protein gene product 9.5 (PGP), neuropeptide Y (NPY), tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and substance P (SP). Perivascular innervation was also examined by transmission electron microscopy. In Lister rat normal livers, perivascular immunoreactive nerve fibres containing PGP, NPY, TH, CGRP and SP were observed around the interlobular blood vessels near the hilum and in the portal tracts. The highest density was seen for PGP, followed in decreasing order, by NPY, TH, CGRP and SP. VIP-immunoreactive nerves were absent. No immunoreactive nerves were observed in the hepatic lobule. In athymic rat livers, the pattern of innervation was similar, except that SP immunoreactivity was more sparse. No perivascular immunoreactive nerves were observed in either MC28 or HT29 tumours. Electron microscopy confirmed the absence of perivascular nerves. Smooth muscle cells were not observed in tumour blood vessel walls. These results are comparable with previous observations on human liver metastases and suggest that the animal models may be suitable for pharmacological studies on vascular manipulation of HAI chemotherapy.     

Characterization of Meibomian gland innervation in the cynomolgus monkey (Macaca fascicularis)

To characterize the innervation of the cynomolgus monkey (Macaca fascicularis) Meibomian (tarsal) glands, upper lids of six cynomolgus monkeys were investigated with electronmicroscopical and double-labeling immunocytochemical methods. Antibodies against calcitonin gene-related peptide (CGRP), dopamine-β-hydroxylase (DBH), neuropeptide Y (NPY), nitric oxide synthase (NOS), protein gene product 9.5 (PGP 9.5), substance P (SP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were used. In addition, sections were processed for NADPH-diaphorase (NADPH-d) histochemistry. Staining for PGP 9.5 and electron microscopy showed that Meibomian gland acini were surrounded by a network of unmyelinated nerves and terminal varicose axons. The terminals contained small agranular (30–60 nm) and large granular vesicles (65–110 nm), and were observed in close contact with the basal lamina of the acini, but never internally to the basal lamina. Meibomian axons showed like-immunore-activity (LI) for the neuropeptides SP, CGRP, NPY, and VIP. In addition, the axons stained for TH, DBH, NOS, and NADPH-d. VIP-LI, NOS- and NADPH-d-positive axons appeared to be more numerous, TH- and DBH-positive axons more rare than others. Most SP-LI axons were double-labelled for CGRP-LI, some for VIP-LI or NPY-LI. In addition, some VIP-LI axons were double-labeled for NPY-LI. NPY/VIP-LI and NPY/SP-LI axons were only observed close to the Meibomian acini. Conversely, NPY-LI colocalized with TH-IR or DBH-IR predominated in perivascular nerves of Meibomian gland vasculature. The close association of varicose axons with the acini of Meibomian glands indicates that nervous signals modulate meibomian secretion. Meibomian gland nerve fibers in the cynomolgus monkey appear to utilize various neuropeptides, catecholamines and nitric oxide as transmitter substances, and seem to derive from the pterygopalatine, superior cervical and trigeminal ganglion respectively.     

Colocalisation of neuropeptides, nitric oxide synthase and immunomarkers for catecholamines in nerve fibres of the adult human vas deferens

Single and double-label immunofluorescence methods were used to determine the distribution and patterns of colocalisation of various neuropeptides and nitric oxide synthase (NOS) with the catecholamine synthesising enzymes tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DβH) in nerve fibres within specimens of adult human vas deferens obtained at vasectomy (age range 28 to 83 y). Cholinergic nerve fibres were immunolabelled with an antiserum to vesicular acetylcholine transporter (VAChT). Using the general nerve marker protein gene product 9.5 (PGP) the density of intramural nerve fibres was found to be similar irrespective of age. Many of these axons, especially in the outer 2 muscle layers were TH and DbH-immunoreactive (IR) and were thus confirmed as noradrenergic. Fewer such axons were seen in the inner longitudinal muscle layer. All the noradrenergic nerve fibres also displayed NPY-immunoreactivity with minor populations containing galanin (GAL) or somatostatin (SOM). Nerve fibres lacking TH and DbH-IR were immunoreactive for VAChT and were sparsely distributed throughout the 2 outer muscle layers but more numerous in the inner muscle layer. Nerves lacking TH and DbH were immunoreactive for NPY and some also contained NOS, VIP or CGRP. These results have been compared with those obtained previously from specimens of human neonatal and infant vas deferens where, in contrast to the present results, NOS and VIP were shown to be colocalised with TH in many of the intramuscular nerve fibres. It thus appears that NOS and VIP cease their coexistence with TH in intramuscular nerve fibres of the human vas deferens between the pre- and postpubertal states. In addition to the intramuscular nerve fibres a VAChT-IR subepithelial nerve plexus occurs in the vas deferens and may control the secretory activity of the lining epithelium. Most of these subepithelial nerve fibres were immunoreactive for NPY and many also contained VIP while minor populations were immunoreactive for NOS, GAL, SOM or SP although fibres containing CGRP were not observed. The neuropeptide content of the subepithelial nerve plexus was similar to that observed in the infant, except for an increased density of VIP-IR nerves, which may reflect greater activity of the lining epithelial cells in the adult vas deferens.     

Characterization of Meibomian gland innervation in the cynomolgus monkey (Macaca fascicularis)

To characterize the innervation of the cynomolgus monkey (Macaca fascicularis) Meibomian (tarsal) glands, upper lids of six cynomolgus monkeys were investigated with electronmicroscopical and double-labeling immunocytochemical methods. Antibodies against calcitonin gene-related peptide (CGRP), dopamine--hydroxylase (DBH), neuropeptide Y (NPY), nitric oxide synthase (NOS), protein gene product 9.5 (PGP 9.5), substance P (SP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were used. In addition, sections were processed for NADPH-diaphorase (NADPH-d) histochemistry. Staining for PGP 9.5 and electron microscopy showed that Meibomian gland acini were surrounded by a network of unmyelinated nerves and terminal varicose axons. The terminals contained small agranular (30–60 nm) and large granular vesicles (65–110 nm), and were observed in close contact with the basal lamina of the acini, but never internally to the basal lamina. Meibomian axons showed like-immunore-activity (LI) for the neuropeptides SP, CGRP, NPY, and VIP. In addition, the axons stained for TH, DBH, NOS, and NADPH-d. VIP-LI, NOS- and NADPH-d-positive axons appeared to be more numerous, TH- and DBH-positive axons more rare than others. Most SP-LI axons were double-labelled for CGRP-LI, some for VIP-LI or NPY-LI. In addition, some VIP-LI axons were double-labeled for NPY-LI. NPY/VIP-LI and NPY/SP-LI axons were only observed close to the Meibomian acini. Conversely, NPY-LI colocalized with TH-IR or DBH-IR predominated in perivascular nerves of Meibomian gland vasculature. The close association of varicose axons with the acini of Meibomian glands indicates that nervous signals modulate meibomian secretion. Meibomian gland nerve fibers in the cynomolgus monkey appear to utilize various neuropeptides, catecholamines and nitric oxide as transmitter substances, and seem to derive from the pterygopalatine, superior cervical and trigeminal ganglion respectively.     

The immunocytochemical distribution of seven peptides in the spinal cord and dorsal root ganglia of horse and pig

Summary The distribution of calcitonin gene-related peptide (CGRP), enkephalin, galanin, neuropeptide Y (NPY), somatostatin, tachykinins and vasoactive intestinal polypeptide (VIP) was compared in cervical, thoracic, lumbar and sacral segmental levels of spinal cord and dorsal root ganglia of horse and pig.In both species, immunoreactivity for the peptides under study was observed at all segmental levels of the spinal cord. Peptide-immunoreactive fibres were generally concentrated in laminae I–III, the region around the central canal, and in the autonomic nuclei. A general increase in the number of immunoreactive nerve fibres was noted in the lumbosacral segments of the spinal cord, which was particularly exaggerated in the case of VIP immunoreactivity. In the horse, some CGRP-, somatostatin- or tachykinin-immunoreactive cell bodies were present in the dorsal horn. In the pig, cells immunoreactive for somatostatin, enkephalin or NPY were noted in a similar location.In the ventral horn most motoneurones were CGRP-immunoreactive in both species. However, in pig many other cell types were CGRP-immunoreactive not only in the ventral horn, but also in laminae V–VI of the dorsal horn.With the exception of enkephalin and NPY immunoreactivity, which was not seen in pig dorsal root ganglia, all peptides studied were localised to neuronal cell bodies and/or fibres in the dorsal root ganglia. In both species, immunolabelled cell bodies were observed in ganglia from cervical, thoracic, lumbar and sacral levels, with the exception of VIP-immunoreactive cells that were detected only in the lumbosacral ganglia. Numerous CGRP- and tachykinin-immunoreactive cell bodies were visualised in both species, while the cells immunolabelled with other peptide antisera were much lower in number.In both species, immunostaining of serial sections revealed that a subset of CGRP-immunoreactive cells co-expressed tachykinin, galanin or somatostatin immunoreactivity. In the horse some enkephalin-immunoreactive cells were also CGRP positive and occasionally combinations of three peptides, e.g. CGRP, tachykinin and galanin or CGRP, tachykinin and enkephalin were identified.The results obtained suggest that the overall pattern of distribution of peptide immunoreactivities is in general agreement with that so far described in other mammals, although some species variations have been observed, particularly regarding the presence of immunoreactive cell bodies in the dorsal horn of the spinal cord.     

Distribution of PGP 9.5, TH, NPY, SP and CGRP immunoreactive nerves in the rat and guinea pig atrioventricular valves and chordae tendineae

The distribution of nerves immunoreactive to protein gene product 9.5 (PGP 9.5), tyrosine hydroxylase (TH), neuropeptide Y (NPY), substance P (SP) and calcitonin gene related peptide (CGRP) antisera was investigated in the atrioventricular valves of the Sprague–Dawley rat and the Dunkin–Hartley guinea pig using confocal and epifluorescence microscopy. No major differences were noted between the innervation of the mitral and tricuspid valves in either species. For all antisera the staining was more extensive in the guinea pig valves. Two distinct nerve plexuses separated by a ‘nearly nerve free’ zone were identified in both species with each antiserum tested. This was most apparent on the anterior cusp of the mitral valve. The major nerve plexus extends from the atrioventricular ring through the basal, intermediate and distal zones of the valves towards the free edge of the valve cusp. These nerve bundles, arranged as primary, secondary and tertiary components, ramify to the free edge of the valve and extend to the attachment of the chordae. They do not contribute to the innervation of the chordae tendineae. The second, minor chordal plexus, runs from the papillary muscles through the chordae tendineae and passes parallel to the free edge of the cusp. The nerves of this minor plexus are interchordal, branching to terminate mainly in the distal zone, free edge of the valve cusp and adjacent chordae tendineae. Some interchordal nerve fibres loop from a papillary muscle up through a chorda, along the free edge and pass down an adjacent chorda into another papillary muscle. The nerve fibres of the major and minor plexuses intermingle although no evidence was found for interconnectivity between them. In the distal zone between the major plexus which extends from the base of the valve and the minor chordal plexus there is a zone completely free of nerves staining with antisera to TH and NPY. Occasional nerves which stained positive for PGP 9.5, SP and CGRP immunoreactivities crossed this ‘nearly nerve free zone’ passing either from the chordal/free edge nerves to the intermediate and basal zones or vice versa. An additional small nerve plexus which displayed immunoreactivity to CGRP antiserum extended from the atrioventricular ring into the basal zone of the valve cusp. Not all chordae tendineae displayed immunoreactive nerve fibres. It is concluded that the innervation patterns of the sensory and sympathetic neurotransmitters and neuropeptides examined in the atrioventricular valves of the rat and guinea pig are ubiquitous in nature. The complexity of the terminal innervation network of the mammalian atrioventricular valves and chordae tendineae may contribute to the complex functioning of these valves in the cardiac cycle.     

Multiple neuropeptides in nerves supplying mammalian lymph nodes: messenger candidates for sensory and autonomic neuroimmunomodulation?

By the use of light microscopic (LM) immunohistochemistry, the presence of peptides and of dopamine beta-hydroxylase (DBH) in nerves supplying mammalian (guinea pig, rat, cat, pig, mouse, human) lymph nodes were examined. In all species, lymph nodes of various somatic and visceral regions were found to contain nerve fibers which stained for neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), substance P (SP), calcitonin gene-related peptide (CGRP) or DBH. SP- and CGRP-immunoreactive (ir) fibers completely overlapped and exhibited the widest distribution. They were present in perivascular, paravascular and many non-vascular fibers travelling in close contact with lymphoid cells. In contrast, NPY-ir fibers coincided with those staining for DBH, prevailed in perivascular plexus and only rarely branched off into lymphoid parenchyma. Alternate staining of adjacent sections revealed that SP/CGRP-ir fibers were different from NPY/DBH-ir fibers. The distribution of VIP-ir fibers was identical to that of PHI-ir fibers and partially overlapped with that of ir-NPY/DBH or ir-SP/CGRP fibers. We conclude that the NPY innervation of lymph nodes is sympathetic noradrenergic while nerves coding for co-existing SP and CGRP are most likely of sensory origin. The nerves containing co-existing VIP and PHI may be of heterogenous origin (sensory, cholinergic sympathetic, and/or parasympathetic). We suggest that these distinct sensory and autonomic peptidergic pathways linking the nervous system with the lymph nodes may play a differential role in bidirectional neuroimmunomodulation.     

Innervation of human adrenal gland and adrenal cortical lesions

The innervation of the human adrenal gland and of cortical lesions was studied in sections of cortical tissue (n=10), hyperplastic cortical tissue (n=3), and tissue from cortical adenomas (n=5) and carcinomas (n=6). The presence and distribution of nerve structures containing neuronal markers indicating sympathetic and parasympathetic innervation were studied by immunohistochemistry and the co-existence and co-localization patterns of the different markers by immunofluorescence. The cortex and hyperplastic cortical tissue had a moderate to rich supply of nerve structures containing the typical neuronal markers: protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), small vesicle synaptic protein type 2 (SV2), and nerves showing immunoreactivity to the adrenergic marker tyrosine hydroxylase (TH). All these immunoreactive nerves were located predominantly adjacent to blood vessels, but also among parenchymal cells. The cortex showed numerous nerve structures containing the neuropeptide substance P (SP), neuropeptide Y (NPY) and vasoactive intestinal protein (VIP), but few nerves containing these peptides were seen in hyperplastic cortical tissue. Typical markers were occasionally observed in cortical adenomas but were not found in carcinomas, except in a few cases where PGP 9.5 and NSE were present, but only adjacent to necrotic areas. Nerves containing NPY and VIP occurred in varying numbers in both adenomas and carcinomas. NPY- and VIP-immunoreactive nerve structures were seen mostly alongside blood vessels. There were several types of co-existence. For instance, NSE/VIP-, TH/VIP- and TH/NPY-immunoreactive nerve structures were often seen in the same trunk, but were only partly co-localized. Received: 19 January 1999 / Accepted: 18 May 1999     

Immunocytochemical investigation of neurovascular relationships in human tooth pulp

This study sought to explore the anatomical relationships between peptidergic nerves and blood vessels within human primary and permanent teeth. Extracted primary and permanent molars (n = 120) were split longitudinally, placed in Zamboni's fixative and the coronal pulps were processed for indirect immunofluorescence. Ten-micrometre-thick serial frozen pulp sections were triple-labelled using combinations of the following antisera: (1) protein gene-product 9.5 (PGP 9.5), a general neuronal marker; (2) one of the neuropeptides, calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP) or neuropeptide Y (NPY); and (iii) the lectin Ulex europeus, a label for vascular endothelium. The mid-coronal pulp region was examined, using fluorescence microscopy, to determine the proportion of blood vessels showing a positive innervation (recorded when PGP 9.5-labelled nerves appeared to intersect the vessel wall). In addition, the percentage of these vascular-related nerves expressing each of the above neuropeptides was recorded. Overall, 20% of pulpal blood vessels appeared to have a positive innervation. In the main these were thick-walled arterioles. Capillaries, venules and lymphatics were mostly devoid of an associated innervation. Ninety-two per cent of vascular-related nerves expressed CGRP, 87% expressed SP, 15% expressed VIP and 80% expressed NPY. There were no significant differences in overall innervation or peptide-related innervation between primary and permanent teeth (P < 0.05, ANOVA), indicating that pulpal blood flow is likely to be subject to similar neurological control mechanisms in both dentitions.     

Distribution and coexistence of neuropeptides in nerve fibres in the temporomandibular joint of late gestation fetal sheep

The density and distribution of nerve fibres immunoreactive to antisera for PGP 9.5 (general neuronal marker), calcitonin gene related peptide (CGRP) and substance P (SP) (markers for sensory neurons), as well as neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and tyrosine hydroxylase (TH) (markers for autonomic fibres), were examined in the temporomandibular joint (TMJ) of late gestation fetal sheep. This work formed part of a project investigating the influence of age and osteoarthritis on the innervation of the TMJ, and was undertaken to determine whether the innervation of the joint at 140 d gestation (17 d before birth) differed from that in the mature adult. Immunofluorescence microscopy was applied to serial sections of the capsule, disc and synovial membrane of 10 joints from 5 fetuses and image analysis was used for the quantitative assessment. The capsule, synovial membrane and the disc contained fibres immunoreactive (IR) to antisera for PGP 9.5, SP and CGRP. NPY-IR fibres were only visible in the loose connective tissue of the capsule. No VIP- or TH-IR nerve fibres were detected in the fetal TMJ. There was no statistically detectable difference between the density of nerve fibres immunoreactive to CGRP or PGP9.5 antisera in the capsule or disc. Substance P-immunoreactivity (IR) was relatively weak in all samples examined. Scattered branches of CGRP-IR fibres were found deep in the disc proper. The lack of receptor endings, other than free nerve endings in the TMJ of the late fetal sheep, might be a reflection of the functional and anatomical immaturity of the TMJ, as reflected in the immature, gross and microscopic appearance of the disc, the inferior joint compartment and articular surface of the condyle at this stage. These results demonstrate that the capsule, synovial membrane and disc in the TMJ of fetal sheep at 140 d gestation age are innervated with sensory fibres, while autonomic fibres are located in the capsule only. The findings also support the view that the disc is innervated at an early stage of life but at a later stage the density of innervation in the central part of the disc regresses and the innervation remains only peripherally in the adult TMJ disc. Further work is required to determine (1) at what stage sympathetic fibres innervate the disc and the synovium, and (2) when the mechanoreceptive nerve endings develop.     

Peptidergic not monoaminergic fibers profusely innervate the young adult human testis

Numerous studies have reported that intratesticular nerves exert important regulatory effects on the functions of the male gonad; however, as yet little is known about their distribution in the young adult human testis. The purpose of this study was to explore whether peptidergic and adrenergic nerves occur in the male gonad of this age, and, if present, to depict their distribution further. Thirty testes were collected from 15 reproductively healthy donors aged 21–32 years. Antibodies against protein gene product 9.5 (PGP 9.5), neuropeptide Y (NPY), C-terminal flanking peptide of NPY (CPON) and vasoactive intestinal peptide (VIP) were employed for immunohistochemical detection of intratesticular peptidergic nerves, and those against dopamine-beta-hydroxylase (DBH) and 5-hydroxytryptamine (5-HT) for monoaminergic ones. The testicular parenchyma exhibited a rich innervation by PGP 9.5-positive fibers, mainly associated with Leydig cell nests, blood vessels, and seminiferous tubules. Numerous NPY- and CPON-immunoreactive (IR) nerves also appeared in the gonads, but the vast majority were confined to blood vessels. A small number of VIP-IR fibers were detected in some arterioles. By contrast, however, no fibers displaying DBH or 5-HT immunoreactivity were observed within the testis. Additionally, expression of PGP-9.5, NPY, CPON, VIP, DBH and 5-HT was found in Leydig cells, PGP 9.5 in spermatogonia, and NPY and CPON in peritubular myoid cells. Our results suggest that the young adult human testis is devoid of monoaminergic nerves but profusely innervated by peptidergic fibers, which may serve as major neuronal regulators for testicular functions at this age.     

Mucosal nerves in endobronchial biopsies in asthma and non-asthma.

To investigate neural events within the airways in asthma, endobronchial biopsies were obtained by fibre-optic bronchoscopy from 8 atopic asthmatic subjects and 8 non-atopic healthy controls. The biopsies were immediately fixed on sampling and subsequently analysed for nerves using specific indirect immunofluorescence with antisera to the neural marker PGP 9.5 and to the neuropeptides vasoactive intestinal peptide (VIP), substance P (SP) and calcitonin gene-related peptide (CGRP). Nerves were present in all the biopsies from both subject groups, with no significant difference between the asthmatic and non-asthmatics. VIP-immunoreactive nerves were equally present in both subject groups, being localized to smooth muscle and glandular sites. No immunoreactive nerves to SP or CGRP could be identified in any biopsy at any location. These in vivo findings do not identify an anatomical neuronal imbalance in asthma.     

Image analysis quantification of peptide-immunoreactive nerves in the skin of patients with Raynaud's phenomenon and systemic sclerosis.

Image analysis quantification was used to assess the results of immunocytochemistry for a neuronal marker and neuropeptides in digital skin biopsies from Raynaud's phenomenon (RP) and systemic sclerosis (SS) patients, to verify the possibility of a selective quantitative abnormality of immunoreactive nerves. The field area of specific immunostaining and nerve counts were evaluated on coded specimens, and the data compared by statistical analysis. Nerves immunoreactive for protein gene product 9.5 (PGP), a marker for neuronal elements, were decreased significantly in epidermal and subepidermal layers of digital skin in RP patients (P less than 0.0001). This change was paralleled by a decrease of calcitonin gene-related peptide (CGRP) immunoreactive nerves in the epidermis and around capillaries in the dermal papillae (P = 0.005). In the skin of RP patients, these changes were readily demonstrated by image analysis, although they were not always apparent on visual screening. In digital skin of SS patients, there was a generalized and very significant decrease of PGP, CGRP, and VIP immunoreactivities in all areas (P less than 0.0001). These results demonstrate that neuropeptide-containing nerves are involved in the digital pathology of RP and SS, and that image analysis quantification is an accurate and sensitive method for assessing morphological changes in pathological samples.     

Calcitonin gene-related peptide, substance P and protein gene product 9.5 immunoreactive axonal fibers in the rat footpad skin following partial sciatic nerve injuries

Chronic constriction injury (CCI) and partial ligation (PSNL) of the sciatic nerve induce a similar neuropathic pain syndrome in rats. We examined calcitonin gene-related peptide (CGRP), substance P (SP) and protein gene product (PGP) 9.5 immunoreactive (IR) axons in the footpad skin after the two types of injury. Four and 14 days after CCI, CGRP- and SP-IR axons in the ipsilateral footpad skin disappeared in most rats, but in one third, sparse CGRP- and SP-IR fibers remained. PGP-IR axons dramatically decreased, but some thick fiber fascicles appeared. At the ultrastructural level, these PGP-IR thick fiber fascicles were characterized as unmyelinated axons surrounded by non-IR Schwann cells. Some of these axons were swollen and irregular in shape. In contrast, 4 days after PSNL, CGRP-, SP-, and PGP-IR axons in the ipsilateral footpad skin were present, though significantly reduced in density, in all rats, and by 14 days all IR fiber densities in the footpad skin partially recovered. The loss of CGRP and SP axons in the footpad skin of the CCI model suggests that sensory nerves containing neuropeptides are not essential in transducing stimuli applied to the footpad skin into neuropathic pain, but the abnormal PGP-IR unmyelinated axons in thick fiber fascicles might play a role. The partial loss and rapid recovery of IR axons in the footpad skin after PSNL shows that the two injury models, causing similar behaviors, are associated with very different patterns of cutaneous innervation at the time when the pain syndrome is well developed.     

Immunohistochemical Properties of the Peripheral Neurons Projecting to the Pig Bulbospongiosus Muscle

Retrograde neuronal tracing and single labelling immunofluorescence methods were used to define the neurochemical content of the peripheral autonomic and sensitive neurons projecting to the male pig striated bulbospongiosus muscle (BSM). The retrograde fluorescent neuronal tracer Fast Blue (FB) was injected into the left bulbospongiosus muscle of four intact impuberal pigs. After a 10‐day survival time, the ipsilateral sacral sympathetic trunk ganglia (STGs), the caudal mesenteric ganglion (CMG), and the sacral spinal ganglia (SGs) were collected from each animal. In FB+ neurons of these ganglia, the presence of cathecolamine‐ (tyrosine hydroxylase‐TH), acetylcholine‐ (vesicular acetylcholine transporter‐VChAT), or nitric oxide‐synthesizing (neuronal Nitric Oxide Synthase‐nNOS) enzymes and of some biologically active peptides (calcitonine gene‐related peptide‐CGRP, Leu‐Enkephaline‐LENK, Neuropeptide Y‐NPY, Substance P‐SP and Vasoactive Intestinal Peptide‐VIP) were studied. The ipsilateral STGs FB+ neurons showed immunoreactivity principally for TH and NPY and in decreasing order for VIP, VChAT, SP, CGRP, nNOS, and LENK. The left CMG FB+ neurons were immunoreactive to TH and NPY, and in smaller proportions for VIP, LENK, VChAT, CGRP, nNOS, and SP. The ipsilateral SGs FB+ neurons resulted immunoractive for CGRP, LENK, NPY, nNOS, SP, and VChAT. The heterogeneous neurochemical content of the peripheral neurons projecting to the pig BSM allows us to hypothesize the involvement of autonomic ganglia in the activity of both blood vessels and striated fibers of the muscle and the involvement of sensory ganglia in the afferent transmission from the muscle to spinal cord and in antidromic mechanisms that causes the relaxation of the BSM blood vessels. Anat Rec, 299:1192–1202, 2016. © 2016 Wiley Periodicals, Inc.     

日本猴椎旁交感神经节中含肽神经元的研究

本实验系应用荧光免疫组织化学的方法观察猴下位腰段椎旁交感神经节(L_(6-7))中神经肽Y,血管活性肠肽,降钙素基因相关肽,和P物质的存在、分布情况以及它们与酪氨酸羟化酶的共存关系。结果表明,大量细胞呈神经肽Y免疫反应阳性,它们在神经节周边分布更为密集。中等数量的血管活性肠肽阳性细胞和小量降钙素基因相关肽细胞散在于神经节内。在经含有Colchiciue的培养液离体孵育12h的标本上,可见中等数量的P物质免疫反应阳性细胞。根据抗酪氨酸羟化酶(TH)抗体的免疫染色结果,神经节内的神经元可分为TH~+和TH~-两群,前者占大多数。相邻切片免疫染色结果表明,几乎所有神经肽Y免疫阳性细胞同时含有TH,而所有血管活性肠肽免疫反应阳性细胞均呈酪氨酸羟化酶免疫反应阴性。神经肽Y与血管活性肠肽无共存关系。降钙素基因相关肽存在于部分血管活性肠肽免疫反应阳性细胞中,即属于VIP~+/TH~-组。从以上结果得出结论,在猴下位腰段椎旁交感神经节中,神经肽Y与血管活性肠肽分别存在于TH~+和TH~-两个细胞群。即神经肽Y存在于TH阳性神经元中,血管活性肠肽和降钙素基因相关肽则存在于TH阴性神经元中。     

Decreased nerve fibers in the oviduct isthmus of women with endometriosis

Oviduct tubal motility is thought to be controlled by hormones and nerves and has been associated with endometriosis. However, it is still not known whether the fallopian tubes in women with endometriosis demonstrate an abnormal distribution of nerve fibers. The objective of this study was to determine the distribution of nerve fibers in the oviduct isthmus in women with and without endometriosis. Histological sections of the oviduct isthmus tissues were obtained from women undergoing hysterectomy for endometriosis (n = 24) and other benign gynecologic diseases (n = 24). The tissues were immunohistochemically stained for protein gene product (PGP) 9.5, substance P (SP), neuropeptide Y (NPY), and vasoactive intestinal peptide (VIP) to reveal all nerve fibers, sensory nerve fibers and sympathetic and parasympathetic nerve fibers. Nerve fibers stained with PGP9.5, VIP and NPY in the oviduct isthmus were all significantly decreased in women with endometriosis as compared with women without endometriosis (P < 0.05). In women with endometriosis, reduced nerve fibers stained with PGP9.5 and SP in the serosal layer, NPY in the muscular and mucosal layers, and VIP in the mucosal layer of the oviduct isthmus were all associated with the severity of the disease (P < 0.05). These results suggest that decreased nerve fibers in the oviduct isthmus in women with endometriosis in comparison to women without may imply a role in the pathogenesis of endometriosis.     

Localisation and quantitation of autonomic innervation in the porcine heart I: conduction system

This study was prompted by the prospect of transgenic pigs providing donor hearts for transplantation in human recipients. Autonomic innervation is important for the control of cardiac dynamics, especially in the conduction system. Our objective was to assess the relative distribution of autonomic nerves in the pig heart, focusing initially on the conduction system but addressing also the myocardium, endocardium and epicardium (see Crick et al. 1999). Quantitative immunohistochemical and histochemical techniques were adopted. All regions of the conduction system possessed a significantly higher relative density of the total neural population immunoreactive for the general neuronal marker protein gene product 9.5 (PGP 9.5) than did the adjacent myocardium. A similar density of PGP 9.5-immunoreactive innervation was observed between the sinus node, the transitional region of the atrioventricular node, and the penetrating atrioventricular bundle. A differential pattern of PGP 9.5-immunoreactive innervation was present within the atrioventricular node and between the components of the ventricular conduction tissues, the latter being formed by an intricate network of Purkinje fibres. Numerous ganglion cell bodies were present in the peripheral regions of the sinus node, in the tissues of the atrioventricular groove, and even in the interstices of the compact atrioventricular node. Acetylcholinesterase (AChE)-containing nerves were the dominant subpopulation observed, representing 60–70% of the total pattern of innervation in the nodal tissues and penetrating atrioventricular bundle. Tyrosine hydroxylase (TH)-immunoreactive nerves were the next most abundant neural subpopulation, representing 37% of the total pattern of innervation in the compact atrioventricular node compared with 25% in the transitional nodal region. A minor population of ganglion cell bodies within the atrioventricular nodal region displayed TH immunoreactivity. The dominant peptidergic nerve supply possessed immunoreactivity for neuropeptide Y (NPY), which displayed a similar pattern of distribution to that of TH-immunoreactive nerve fibres. Calcitonin gene-related peptide (CGRP)-immunoreactive nerves represented 8–9% of the total innervation of the nodal tissues and penetrating atrioventricular bundle, increasing to 14–19% in the bundle branches. Somatostatin-immunoreactive nerve fibres were relatively sparse (4–13% of total innervation) and were most abundant in the nodes, especially the compact atrioventricular node. The total pattern of innervation of the porcine conduction system was relatively homogeneous. A substantial proportion of nerve fibres innervating the nodal tissues could be traced to intracardiac ganglia indicative of an extensive intrinsic supply. The innervation of the atrioventricular node and ventricular conduction tissues was similar to that observed in the bovine heart, but markedly different to that of the human heart. It is important that we are aware of these findings in view of the future use of transgenic pig hearts in human xenotransplantation.