Regional innervation of the heart in the goldfish,Carassius auratus: A confocal microscopy study

The intracardiac nervous system represents the final common pathway for autonomic control of the vertebrate heart in maintaining cardiovascular homeostasis. In teleost fishes, details of the organization of this system are not well understood. Here we investigated innervation patterns in the heart of the goldfish, a species representative of a large group of cyprinids. We used antibodies against the neuronal markers zn‐12, acetylated tubulin, and human neuronal protein C/D, as well as choline acetyltransferase, tyrosine hydroxylase, nitric oxide synthetase, and vasoactive intestinal polypeptide (VIP) to detect neural elements and their transmitter contents in wholemounts and sections of cardiac tissue. All chambers of the heart were innervated by choline acetyltransferase‐positive axons, implying cholinergic regulation; and by tyrosine hydroxylase‐containing axons, implying adrenergic regulation. The mean total number of intracardiac neurons was 713 ± 78 (SE), nearly half of which were cholinergic. Neuronal somata were mainly located in a ganglionated plexus around the sinoatrial valves. Somata were contacted by cholinergic, adrenergic, nitrergic, and VIP‐positive terminals. Putative pacemaker cells, identified by immunoreactivity for hyperpolarization activated, cyclic nucleotide‐gated channel 4, were located in the base of the sinoatrial valves, and this region was densely innervated by cholinergic and adrenergic terminals. We have shown that the goldfish heart possesses the necessary neuroanatomical substrate for fine, region‐by‐region autonomic control of the myocardial effectors that are involved in determining cardiac output. J. Comp. Neurol. 522:456–478, 2014. © 2013 Wiley Periodicals, Inc.     

Origin of sympathetic and sensory innervation of the elbow joint in the rat: A retrograde axonal tracing study with wheat germ agglutinin conjugated horseradish peroxidase

After injection of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) into the elbow joint of adult rats, labeled neurons were found in the stellate and the T2-T4 ganglia of the ipsilateral sympathetic trunk, and also in dorsal root ganglia at the C4–T4 levels. Most labeled sympathetic cells, 90% or more, were located in the stellate ganglion. The sensory innervation to the joint originated mainly from the dorsal root ganglia at the levels of C7–T1.     

Prolonged sympathetic innervation of sensory neurons in rat thoracolumbar dorsal root ganglia during chronic colitis

Background Peripheral irritation‐induced sensory plasticity may involve catecholaminergic innervation of sensory neurons in the dorsal root ganglia (DRG). Methods Catecholaminergic fiber outgrowth in the thoracolumbar DRG (T13‐L2) was examined by tyrosine hydroxylase (TH) immunostaining, or by sucrose‐potassium phosphate‐glyoxylic acid histofluorescence method. TH level was examined by Western blot. Colonic afferent neurons were labeled by retrograde neuronal tracing. Colitis was induced by intracolonic instillation of tri‐nitrobenzene sulfonic acid (TNBS). Key Results The catecholaminergic fibers formed ‘basket‐like’ structures around the DRG cells. At 7 days following TNBS treatment, the number of DRG neurons surrounded by TH‐immunoreactive fibers and the protein levels of TH were significantly increased in T13, L1, and L2 DRGs (two‐ to threefold, P < 0.05). The DRG neurons that were surrounded by TH immunoreactivity were 200 kDa neurofilament‐positive, but not isolectin IB4‐positve or calcitonin gene‐related peptide‐positive. The TH‐immunoreactive fibers did not surround but adjoin the specifically labeled colonic afferent neurons, and was co‐localized with glial marker S‐100. Comparison of the level of TH and the severity of colonic inflammation showed that following TNBS treatment, the degree of colonic inflammation was most severe at day 3, subsided at day 7, and significantly recovered by day 21. However, the levels of TH in T13‐L2 DRGs were increased at both 3 days and 7 days post TNBS treatment and persisted up to 21 days (two‐ to fivefold increase, P < 0.05) as examined. Conclusions & Inferences Colonic inflammation induced prolonged catecholaminergic innervation of sensory neurons, which may have relevance to colitis‐induced chronic visceral hypersensitivity and/or referred pain.     

Parasympathetic, sympathetic, and sensory interactions in the iris: nerve growth factor regulates cholinergic ciliary ganglion innervation in vivo

Interactions between peptidergic sensory nerves, noradrenergic sympathetic nerves, and cholinergic parasympathetic fibers were examined in the rat iris. The putative peptide neurotransmitter, substance P (SP), was used as an index of the trigeminal sensory innervation, tyrosine hydroxylase (TH) activity served to monitor the sympathetic fibers, and choline acetyltransferase (CAT) activity was used as an index of the parasympathetic innervation. Destruction of the sympathetic innervation by neonatal administration of 6-hydroxydopamine resulted in increased SP development and a smaller increase in CAT activity in the iris. Moreover, trigeminal ablation resulted in an increase in both TH and CAT activities. Finally, ciliary ganglionectomy resulted in increased SP and a smaller increase in TH activity in the iris. Administration of nerve growth factor (NGF) into the anterior chamber substantially increased both SP and TH activity in the iris and also increased CAT activity to a lesser extent. Moreover, administration of anti-NGF into the anterior chamber prevented both the sympathectomy-induced increases in SP and CAT, and the increases in TH and CAT activities after trigeminal ablation, suggesting that NGF mediated these increases. These observations suggest that the sympathetic, sensory, and parasympathetic innervations of the iris interact by altering availability of NGF elaborated by the iris. Regulation of iris CAT activity was examined in greater detail. Injection of the cholinergic toxin, AF64A, into the anterior chamber concurrently with ablation of the sympathetic and sensory innervations paradoxically increased CAT activity, whereas AF64A alone decreased CAT activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Imbalance between sympathetic and sensory innervation in peritoneal endometriosis

To investigate possible mechanisms of pain pathophysiology in patients with peritoneal endometriosis, a clinical study on sensory and sympathetic nerve fibre sprouting in endometriosis was performed.Peritoneal lesions (n = 40) and healthy peritoneum (n = 12) were immunostained and analysed with anti-protein gene product 9.5 (PGP 9.5), anti-substance P (SP) and anti-tyrosine hydroxylase (TH), specific markers for intact nerve fibres, sensory nerve fibres and sympathetic nerve fibres, respectively, to identify the ratio of sympathetic and sensory nerve fibres. In addition, immune cell infiltrates in peritoneal endometriotic lesions were analysed and the nerve growth factor (NGF) and interleukin (IL)-1β expression was correlate with the nerve fibre density.Peritoneal fluids from patients with endometriosis (n = 40) and without endometriosis (n = 20) were used for the in vitro neuronal growth assay. Cultured chicken dorsal root ganglia (DRG) and sympathetic ganglia were stained with anti-growth associated protein 43 (anti-GAP 43), anti-SP and anti-TH.We could detect an increased sensory and decreased sympathetic nerve fibres density in peritoneal lesions compared to healthy peritoneum. Peritoneal fluids of patients with endometriosis compared to patients without endometriosis induced an increased sprouting of sensory neurites from DRG and decreased neurite outgrowth from sympathetic ganglia.In conclusion, this study demonstrates an imbalance between sympathetic and sensory nerve fibres in peritoneal endometriosis, as well as an altered modulation of peritoneal fluids from patients with endometriosis on sympathetic and sensory innervation which might directly be involved in the maintenance of inflammation and pain.     

Functional assessment of the sympathetic innervation of the microcirculation of the lower urinary tract: A preliminary report

This paper presents preliminary data on a new method for testing the sympathetic innervation of the urothelium. A flexible laser Doppler probe was introduced into the urethra of two females and two male subjects. The percentage fall in laser Doppler flux following generalized sympathetic stimulation by taking an inspiratory gasp was measured. This resulted in 36%, 32%, 68% and 34% mean drop in urothelial blood flux. In the female subjects, the probe was advanced into the bladder and the procedure repeated, and the gasp resulted in 60% and 83% drop in flux. With laser Doppler fluxmetry, fall in microcirculatory blood flow associated with a generalized increase in sympathetic tone, therefore can be demonstrated. This method may be useful in the assessment of the integrity of the sympathetic innervation of the urothelium in patients with suspected autonomic dysfunction of the genitourinary tract.     

Sustained cerebral vasoconstriction during bilateral sympathetic stimulation in anesthetized rabbits

Temporal aspects of bilateral sympathetic nerve stimulation on cerebral blood flow (CBF) were examined in anesthetized rabbits (n = 7). CBF ranged from 32 to 50 ml/min per 100 g. Bilateral stimulation reduced blood flow by 17-31% to cerebrum, diencephalon-mesencephalon and cerebellum, and responses were constant between 2 and 6 min of stimulation. Sustained cerebral vasoconstriction is consistent with an important role for sympathetic nerves in the regulation of CBF.     

Embryonic expression of pituitary adenylate cyclase-activating polypeptide in sensory and autonomic ganglia and in spinal cord of the rat

Pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide that is related structurally to vasoactive intestinal polypeptide (VIP), has been shown to stimulate neuronal growth and differentiation, indicating a possible function in the development of the nervous system. Studies have indicated that the PACAP receptor is expressed during development, but data on PACAP expression are limited mainly to postnatal development. In the present study, we used immunohistochemistry and in situ hybridization histochemistry to examine the expression of PACAP in autonomic and sensory ganglia and spinal cord of rat fetuses at embryonic days 12–21 (E12–E21). PACAP immunoreactivity was visualized by using a specific monoclonal anti-PACAP antibody to detect both PACAP-38 and PACAP-27, and PACAP mRNA was visualized by using a [³³P]-labeled cRNA-probe. PACAP⁺ nerve fibers were observed in the spinal cord as early as E13. At E14, PACAP-immunoreactive nerve fibers projected to the sympathetic trunk, where few PACAP⁺ nerve cell bodies were seen from E15. On the same embryonic day, PACAP-immunoreactive nerve cell bodies appeared in the intermediolateral column of the spinal cord. From E15 to E16, PACAP-immunoreactive nerve cell bodies were visible within sensory and autonomic ganglia, such as the dorsal root, the trigeminal, the sphenopalatine, the otic, the submandibular, and the nodose ganglia. At E16, PACAP⁺ nerve fibers were innervating the adrenal medulla, and immunoreactive fibers could also be observed in the superior cervical ganglion, in which PACAP-immunoreactive cell bodies were detected occasionally from E18. The synthesis of PACAP in neuronal cell bodies was confirmed by the demonstration of PACAP mRNA with in situ hybridization histochemistry. Thus, in all of the structures examined, PACAP appeared at roughly the same embryonic stage and, thereafter, increased to the adult level before birth. Because PACAP occurred with the same distribution pattern as that described in the adult rat, there is no evidence for transient expression. The early expression of PACAP suggests a possible role for the peptide in the developing nervous system. J. Comp. Neurol. 394:403–415, 1998. © 1998 Wiley-Liss, Inc.     

Evaluation of cutaneous autonomic innervation in idiopathic sensory small-fiber neuropathy

To evaluate the loss of autonomic nerve fibers in patients with clinical pure small-fiber sensory neuropathy, we performed skin punch biopsies in 17 and 15 age- and sex-matched controls. Biopsies were taken 10 cm above the lateral malleolus, and 5-mum sections were stained with hematoxylin and eosin and the panaxonal marker protein gene product (PGP) 9.5. Positively stained fibers, represented as dots, innervating the erector pili muscles, arterioles, and sweat glands (SG) were counted. The ratios between the number of nerve fibers and nuclei of each structure were calculated. The autonomic innervation was significantly reduced in the patients' group compared with controls in all the examined autonomic-innervated structures: SG (0.27 +/- 0.15 vs. 0.66 +/- 0.37, p = 0.001), arterioles (0.38 +/- 0.32 vs. 0.86 +/- 0.45, p=0.002), and the erector pili muscle (0.58 +/- 0.27 vs. 1.23 +/- 0.87, p = 0.036). Our results suggest that autonomic involvement occurs in patients with sensory small-fiber neuropathy and that punch skin biopsy using thin sections is a simple and convenient method to detect these dermal autonomic small-fiber abnormalities.     

5-HT innervation of reticulospinal neurons and other brainstem structures in lamprey

In order to determine if reticulospinal neurons involved in the control of locomotion and responsive to exogenously applied 5-hydroxtryptamine (5-HT) are innervated by fibers that contain serotonin, the serotoninergic innervation of reticulospinal neurons, identified by retrograde labeling with fluorescein-conjugated dextran-amine (FDA), was investigated by immunohistochemistry in the lamprey brainstem. A widespread distribution of 5-HT immunoreactive (5-HT-ir) fibers was seen within the basal plate of the brainstem, an area containing reticulospinal somata and dendritic arborizations. Numerous 5-HT varicose fibers were found in close relation to large reticulospinal cell bodies, particularly in the middle and anterior rhombencephalic reticular nuclei (MRRN and ARRN). Some of these reticulospinal somata were surrounded by a very dense pericellular 5-HT innervation. 5-HT-ir fibers were also seen in other brain structures that are known to influence reticulospinal neurons such as the rhombencephalic alar plate containing sensory relay interneurons, cranial nerves (III–X), cerebellum, and tectum. These findings suggest that, as in the spinal cord, motor behavior controlled by reticulospinal neurons may be subject to a serotoninergic modulation. © 1994 Wiley-Liss, Inc.     

Motor, sympathetic and sensory innervation of rat skeletal muscles

This study reports on the location, number and size of motor, sympathetic and sensory neurons innervating the following muscles of rat: quadriceps femoris (QF), tibialis anterior (TA), extensor digitorum longus (EDL), peroneus longus (PL), gastrocnemius medius (GM) and soleus (SOL). Cells were labelled by application of horseradish peroxidase (HRP) to transected muscle nerves. Counts of neurons were compared with counts of myelinated (MF) and unmyelinated (UMF) fibers in normal, deafferented and chemically sympathectomized nerves. The topographical arrangement of spinal motor nuclei resembled that reported previously in other mammals and birds. Sensory somata were aggregated without precise somatotopic organization, preferentially in one of the lumbar dorsal root ganglia at a segmental level corresponding to that of the motor innervation. Because lumbar sympathetic ganglia were often poorly circumscribed, the segmental position of sympathetic ganglion cells could not be localized with certainty. Sensory and sympathetic somata demonstrated a unimodal size-frequency distribution, while QF, TA and PL motoneurons could be subdivided according to size in alpha and gamma cells. For all muscles except unsuccessfully deafferented QF, counts of motor fibers after deafferentation correlated closely with counts of labelled motoneurons. Similarly, estimates of sympathetic axons, averaging 30,7% of the UMF, in most instances exceeded only marginally the ganglion cell population. In contrast, the number of peripheral afferent fibers outnumbered markedly that of sensory cell bodies, with an average of 2.8 axons per ganglion cell.     

Regional distribution and extrinsic innervation of intrinsic cardiac neurons in the guinea pig.

Mammalian intrinsic cardiac neurons subserve different functions in different cardiac regions, but the regional anatomical organisation of the intracardiac nervous system is not well understood. We investigated the quantitative and qualitative distribution of cholinergic and adrenergic elements, and the intracardiac pathways of extrinsic cardiac nerves, in whole-mount preparations of guinea pig atria. Protein gene product 9.5 immunoreactivity (PGP 9.5-IR) marked intracardiac neuronal elements; immunoreactions for choline acetyltransferase (ChAT-IR) and tyrosine hydroxylase (TH-IR) distinguished cholinergic and adrenergic components, respectively. Catecholamine-containing components were identified by aldehyde-induced fluorescence histochemistry. Mean total number of atrial neurons was 1510+/-251 (SE); 85% of these occurred in ganglia of < or = 20 neurons. All neuronal somata expressing PGP 9.5-IR also expressed ChAT-IR, suggesting that these neurons were cholinergic. Right (RA) and left (LA) atria had statistically similar neuronal densities (6.4+/-1.2 and 2.4+/-0.7 neurons/mm2, respectively; analysis of variance, P< or =0.05). Neurons in RA were concentrated intercavally; LA neurons were concentrated near pulmonary vein ostia. Greatest density occurred in the interatrial septum (16.3+/-4.0 neurons/mm2). No neuronal somata expressed TH-IR or contained detectable amines but these elements were expressed by somata of small cells (mean total 124+/-33) throughout the atria, primarily associated with ganglia. Amine- and TH- containing varicosities were also present in ganglia, representing potential sites for adrenergic modulation of ganglionic neurotransmission. Branches of extrinsic cardiopulmonary and vagus nerves were distributed to all parts of both atria. The organisation of the intracardiac nervous system revealed in this study will facilitate further investigations of regional autonomic control of the heart.     

Diversity of sympathetic vasoconstrictor pathways and their plasticity after spinal cord injury

Sympathetic vasoconstrictor pathways pass through paravertebral ganglia carrying ongoing and reflex activity arising within the central nervous system to their vascular targets. The pattern of reflex activity is selective for particular vascular beds and appropriate for the physiological outcome (vasoconstriction or vasodilation). The preganglionic signals are distributed to most postganglionic neurones in ganglia via synapses that are always suprathreshold for action potential initiation (like skeletal neuromuscular junctions). Most postganglionic neurones receive only one of these “strong” inputs, other preganglionic connections being ineffective. Pre- and postganglionic neurones discharge normally at frequencies of 0.5–1 Hz and maximally in short bursts at <10 Hz. Animal experiments have revealed unexpected changes in these pathways following spinal cord injury. (1) After destruction of preganglionic neurones or axons, surviving terminals in ganglia sprout and rapidly re-establish strong connections, probably even to inappropriate postganglionic neurones. This could explain aberrant reflexes after spinal cord injury. (2) Cutaneous (tail) and splanchnic (mesenteric) arteries taken from below a spinal transection show dramatically enhanced responses in vitro to norepinephrine released from perivascular nerves. However the mechanisms that are modified differ between the two vessels, being mostly postjunctional in the tail artery and mostly prejunctional in the mesenteric artery. The changes are mimicked when postganglionic neurones are silenced by removal of their preganglionic input. Whether or not other arteries are also hyperresponsive to reflex activation, these observations suggest that the greatest contribution to raised peripheral resistance in autonomic dysreflexia follows the modifications of neurovascular transmission.     

Quantitative analysis of the number and distribution of neurons richly innervated by GABA-immunoreactive axons in the rat superior cervical ganglion

The superior cervical ganglion of rats contains a considerable number of nerve fibers with GABA-like immunoreactivity which show a nonuniform distribution within the ganglion. The topography of these fibers has been analyzed by using antibodies raised against GABA-BSA-glutaraldehyde complexes. GABA-positive axons and axon varicosities accumulated around a subpopulation of principal ganglion cells forming basketlike patterns. These neurons richly innervated by GABA-positive axons (RIG-neurons) in turn were aggregated in patches with strong immunoreactivity. The size and packing density of the patches containing RIG-neurons and GABA-positive axons approaching them had rostral-to-caudal and medial-to-lateral gradients. Similar patterns were found in right and left ganglia. In five ganglia, a quantitative analysis revealed on average 1,344 RIG-neurons per ganglion representing about 5% of the total neuron population, with small variations (standard deviation 122) despite the highly variable shape of the ganglia. The distribution of RIG-neurons resembles that of neurons sending their axons into the internal carotid nerve. To check this possible correlation, HRP was injected into the eye and applied to the transected external carotid nerve. Double staining for the retrogradely transported peroxidase and GABA immunohistochemistry revealed that RIG-neurons formed a small subpopulation of retrogradely labelled neurons in both experiments. This suggests that RIG-neurons innervate various target organs. This conclusion is in agreement with the observation that RIG-neurons also exist in other sympathetic ganglia. Data presented suggest that sympathetic ganglion cells can be classified on the basis of non-uniform innervation patterns formed by axons that use different neurotransmitters.     

Calcitonin-gene-related-peptide-immunoreactive innervation of the rat head with emphasis on specialized sensory structures

The distribution of calcitonin-gene-related peptide-like immunoreactivity (CGRP-IR) was studied in sections of decalcified rat head and selected whole-mount preparations in order to address the complex peptidergic innervation patterns in peripheral cephalic specialized zones and to examine neuronal ganglia in situ. Labeled neuron somata in trigeminal, glossopharyngeal, and vagal ganglia comprised a large proportion of small to medium size type B ganglion cells. Parasympathetic ganglia (ciliary, otic, sphenopalatine, submandibular) revealed a small population of labeled somata and numerous perisomatic IR axons, whereas sympathetic ganglion cells (superior cervical) were devoid of label though richly innervated by perisomatic IR axons. The gustatory geniculate ganglion contained only a few labeled neurons and axons. Coarse peripheral CGRP-IR axons were traced to skeletal muscle motor end plates (e.g., lingual, tensor tympani, etc.), and thin sensory axons most densely innervated the cornea, iris, general integument, all mucosal epithelia lining the tympanic, nasal, sinus and oropharyngeal cavities, and the cerebral meninges. Blood vessels, glands, ducts, and their orifices were often heavily innervated, and specific specializations and exceptions are discussed. Distinctive patterns of IR innervation characterized the various specialized sensory systems, including 1) cochlear and vestibular hair cells; 2) lingual, palatal, oropharyngeal, and laryngoepiglottal taste buds; 3) main olfactory epithelium and axons projecting to glomeruli in specific sectors of main olfactory bulb; 4) septal-olfactory organ; 5) vomeronasal organ; and 6) the nervus terminalis system. Secretory epithelia (ciliary body, choroid plexus, and stria vascularis) were notably lacking in CGRP-IR. Despite the multiplicity of functionally distinct CGRP neuronal and axonal populations, certain generalizations merit consideration. The extensive innervation of chemosensory nasal and oral epithelia may contribute to specific chemical sensitivities (e.g., relating to olfactory and gustatory senses) as well as evoking "nociceptive" responses to chemical irritants as part of a "common chemical sense." An efferent role for some of these peptidergic afferent axons may also be inferred from their specific distributions. Sites involved in regulating access to and sensitivity of sense organs to external stimuli (e.g., cochlear and vestibular hair cells, taste bud orifices, and main olfactory epithelium) are heavily innervated. Other IR axons are in position to exert control over airflow through nasal turbinates, glandular secretion, blood circulation, and duct transport systems.(ABSTRACT TRUNCATED AT 400 WORDS)     

Nerve growth factor expression in parasympathetic neurons: regulation by sympathetic innervation

Interactions between sympathetic and parasympathetic nerves are important in regulating visceral target function. Sympathetic nerves are closely apposed to, and form functional synapses with, parasympathetic axons in many effector organs. The molecular mechanisms responsible for these structural and functional interactions are unknown. We explored the possibility that Nerve Growth Factor (NGF) synthesis by parasympathetic neurons provides a mechanism by which sympathetic-parasympathetic interactions are established. Parasympathetic pterygopalatine ganglia NGF-gene expression was examined by in situ hybridization and protein content assessed by immunohistochemistry. Under control conditions, NGF mRNA was present in approximately 60% and NGF protein was in 40% of pterygopalatine parasympathetic neurons. Peripheral parasympathetic axons identified by vesicular acetylcholine transporter-immunoreactivity also displayed NGF immunoreactivity. To determine if sympathetic innervation regulates parasympathetic NGF expression, the ipsilateral superior cervical ganglion was excised. Thirty days postsympathectomy, the numbers of NGF mRNA-positive neurons were decreased to 38% and NGF immunoreactive neurons to 15%. This reduction was due to a loss of sympathetic nerve impulse activity, as similar reductions were achieved when superior cervical ganglia were deprived of preganglionic afferent input for 40 days. These findings provide evidence that normally NGF is synthesized by parasympathetic neurons and transported anterogradely to fibre terminals, where it may be available to sympathetic axons. Parasympathetic NGF expression, in turn, is augmented by impulse activity within (and presumably transmitter release from) sympathetic axons. It is suggested that parasympathetic NGF synthesis and its modulation by sympathetic innervation provides a molecular basis for establishment and maintenance of autonomic axo-axonal synaptic interactions.     

低强度中频电刺激健康男性腰交感神经节后下肢远端皮肤血流的改变*

背景：飞行人员由于长时间保持固定坐姿,腿部活动范围受限,易引起腿部血液循环不畅,产生疲劳感。研究显示中频电流具有明显的促进局部血液循环的作用。 目的：探讨低强度中频电刺激腰交感神经节对健康男性下肢远端皮肤血液循环的影响,并与静态干扰电疗法作比较。 方法：在39名健康男性腰部交感神经节(T10~L2)放置中频电电极,右内踝关节上方2 cm处放置激光多普勒血流监测仪探头,电流强度为感觉阈。分别给予调制中频电刺激、静态干扰电刺激及不通电刺激。激光多普勒血流监测仪记录静息15 min后及电刺激20 min末的血流值。 结果与结论：与基线值比较,经调制中频电刺激的受试者下肢远端皮肤血流灌注量有所增加,而未给予电刺激及静态干扰电刺激的受试者下肢远端皮肤血流灌注量有所减少,尤其是经静态干扰电刺激后,明显低于基线值(P < 0.05)。说明调制中频电刺激可以改善下肢的血液循环,对长时间保持固定坐姿产生的疲劳有缓解功能。     

Localization of cholecystokininlike immunoreactivity in the rat spinal cord,with particular reference to the autonomic innervation of the pelvic organs

The distribution of cholecystokinin in the spinal cord was investigated by immunohistochemistry. Throughout the length of the spinal cord cholecystokinin immunoreactivity was found in laminae I and II, in the spinal re-ticular nucleus, and in the surroundings of the central canal. On the basis of the cholecystokinin pattern lamina II could be divided into a dorsal and ventral part. In the lumbar and sacral spinal cord additional terminal fields of cholecystokinin immunoreactive boutons unique to these levels were found. They corresponded to the intermediolateral nucleus and to the medial lumbar sympathetic nucleus dorsal to the central canal in the first and second lumbar segment. Also the intermediolateral nucleus in L₆–S₁ received a dense cholecystokinin positive input. Moreover, the area surrounding the central canal in L₆–S₁, contained many cholecystokinin immunoreactive structures. Combined retrograde tracing and immunocytochemistry revealed that the two cholecystokinin terminal fields characteristic for L₁–L₂ and that sur-rounding the intermediolateral nucleus in L₆–S₁ were situated corresponding to preganglionic neurons innervating pelvic organs through the hypo-gastric nerve or the pelvic nerves. It thus appears that the unique lumbosacral cholecystokinin is related to nuclei influencing pelvic structures, pointing to a special need for regulation of the organs involved in evacuation and sexual functions. Moreover, it is demonstrated that the caudal part of the spinal sympathetic system differs from the more cranial part with respect to type of afferent connections. The origin of the spinal cholecystokinin was investigated and it was found that neither complete transection of the spinal cord nor ipsilateral sectioning of three or four dorsal roots induced visible changes in the cholecystokinin staining pattern. Treatment of the caudal spinal cord with colchicine revealed the presence of cholecystokinin immunoreactive neurons in the intermediate gray, at the lateral border of the dorsal horn, in the dorsal horn proper, and in the substantia gelatinosa. These findings indicate that the majority of spinal cholecystokinin has a spinal origin.     

Quantitative and ultrastructural study of serotonin innervation of the globus pallidus in squirrel monkeys

The present immunohistochemical study was aimed at characterizing the serotonin (5‐HT) innervation of the internal (GPi) and external (GPe) pallidal segments in the squirrel monkey (Saimiri sciureus) with an antibody against the 5‐HT transporter (SERT). At the light microscopic level, unbiased counts of SERT+ axon varicosities showed that the density of innervation is similar in the GPi (0.57 ± 0.03 × 10⁶ varicosities/mm³ of tissue) and the GPe (0.60 ± 0.04 × 10⁶), with the anterior half of both segments being more densely innervated than the posterior half. Dorsoventral and mediolateral decreasing gradients of SERT varicosities occur in both pallidal segments, but are statistically significant only in the GPi. The neuronal density being significantly greater in the GPe (3.41 ± 0.23 × 10³ neurons/mm³) than in the GPi (2.90 ± 0.11 × 103), the number of 5‐HT axon varicosities per pallidal neuron was found to be superior in the GPi (201 ± 27) than in the GPe (156 ± 26). At the electron microscopic level, SERT+ axon varicosities are comparable in size and vesicular content in GPi and GPe, where they establish mainly asynaptic contacts with unlabeled profiles. Less than 25% of SERT+ varicosities display a synaptic specialization, which is of the symmetrical or asymmetrical type and occurs exclusively on pallidal dendrites. No SERT+ axo‐axonic synapses are present, suggesting that 5‐HT exerts its well‐established modulatory action upon various pallidal afferents mainly through diffuse transmission, whereas its direct control of pallidal neurons results from both volumic and synaptic release of the transmitter.