Preganglionic fibers in the rat hypogastric nerve project bilaterally to pelvic ganglia

Stimulation of the hypogastric nerve (HGN) often evokes bilateral responses in some pelvic organs. Retrograde labeling studies indicate that axons of postganglionic neurons often cross to the opposite side. However, there is little information available as to whether preganglionic fibers in the HGN have a contralateral projection to pelvic ganglia. A retrograde tracer was injected into the left major pelvic ganglion (MPG) in rats receiving various lesions of preganglionic nerves (HGN and pelvic nerve, PN). The lumbar spinal cord was then examined for location and number of dye-filled neurons. In a second approach, the incidence of synaptophysin immunoreactivity (SN-IR) perineuronal profiles (baskets) was examined in the MPG and in the accessory pelvic ganglia (APG) after nerve lesions. Labeled neuronal profiles were found in spinal cord nuclei (Lumbar_1–2) after dye injection of the MPG in animals with an intact contralateral HGN. Cutting both HGNs virtually eliminated dye labeling in the lumbar cord, as did severing commissural branches (CB) between pelvic ganglia (leaving the contralateral HGN intact). Some SN-IR baskets were found in the left APG when only the contralateral HGN was intact, but baskets were rare when all four preganglionic nerves were cut. It could not be determined whether the HGN projects to the contralateral MPG, since SN-IR baskets were numerous in the MPG even when all four nerves were cut. This study has shown that some preganglionic fibers in the HGN synapse on neurons in contralateral pelvic ganglia. Both the APG and MPG receive contralateral innervation, but it is likely that neurons in the APG are the primary target of this input. Thus, in addition to crossing postganglionic fibers, a portion of the bilateral control of pelvic tissues is accomplished by preganglionic fibers which target autonomic neurons in contralateral ganglia. Anat. Rec. 252:229–234, 1998. © 1998 Wiley-Liss, Inc.     

Remodelling of connections in pelvic ganglia after hypogastric nerve crush

Pelvic ganglia innervate the urogenital organs and contain both sympathetic and parasympathetic neurons. Previous studies have shown that within days of cutting either the lumbar or sacral preganglionic axons that innervate pelvic ganglia, many axon collaterals grow and appear to form specific connections with denervated pelvic neurons. Here we have examined the longer term consequences of partial deafferentation by studying pelvic ganglia up to 7 weeks after hypogastric nerve (HGN) crush, a lesion which also allows faster regeneration of spinal axons. Noradrenergic neurons were denervated by HGN crush, as demonstrated by loss of varicosities immunostained for the synaptic proteins, synaptophysin and synapsin. A week after HGN crush, axon collaterals grew from parasympathetic pelvic ganglion neurons, shown by the presence of numerous varicose fibers immunostained for vasoactive intestinal peptide (VIP). These VIP fibers were poorly stained or unstained for synaptophysin, even after 7 weeks. At early post-operative times the VIP fibers grew irregularly; however, with longer post-operative times they appeared to target particular VIP-negative, noradrenergic neurons. Our results also indicate that some lumbar preganglionic axons regenerated during the post-operative period, although this only affected a minority of sympathetic neurons. These reinnervated sympathetic neurons were not associated with VIP fibers, suggesting that the new intrinsic connections may have precluded regeneration or targeting of preganglionic axons. Together these results demonstrate that there is considerable remodelling within pelvic ganglia after partial deafferentation. This occurs under conditions where spinal preganglionic axons can regenerate. New intra-ganglionic connectivity may be permanent and may impact on this regeneration.     

Vasoconstrictor, vasodilator and pilomotor pathways in sympathetic ganglia of guinea-pigs.

Triple-labelling immunofluorescence and retrograde axonal tracing with fluorescent dyes have been combined to identify and characterize the neuropeptide content of vasoconstrictor, vasodilator and pilomotor neurons in the lumbar sympathetic ganglia of guinea-pigs. Postganglionic noradrenergic pilomotor neurons lacked immunoreactivity to neuropeptide Y and comprised up to about 30% of postganglionic neurons. Most post-ganglionic noradrenergic neurons that contained neuropeptide Y immunoreactivity were likely to be vasoconstrictor neurons, although some noradrenergic neurons containing neuropeptide Y projected to pelvic viscera. Vasoconstrictor neurons comprised up to about 60% of postganglionic neurons. About 15% of postganglionic neurons were non-noradrenergic and contained immunoreactivity to vasoactive intestinal peptide, neuropeptide Y and dynorphin. They mostly innervated blood vessels supplying skeletal muscles and were likely to be vasodilator neurons. Endings of presumed preganglionic neurons containing immunoreactivity to substance P were exclusively associated with vasodilator neurons. Conversely, presumed preganglionic endings containing immunoreactivity to calcitonin gene-related peptide were exclusively associated with vasoconstrictor neurons, although not all vasoconstrictor neurons had such endings associated with them. Presumed preganglionic terminals containing immunoreactivity to enkephalin were associated with some postganglionic neurons in each functional class. These results show that preganglionic and postganglionic sympathetic neurons lying in different functional pathways can be distinguished by their neuropeptide content as well as their projections. The identification of neurochemically distinct functional pathways begins to explain how the sympathetic nervous system is organized to allow the precise control of discrete target tissues.     

Functional segregation within the pelvic nerve of male rats: a meso- and microscopic analysis

The pelvic splanchnic nerves are essential for pelvic organ function and have been proposed as targets for neuromodulation. We have focused on the rodent homologue of these nerves, the pelvic nerves. Our goal was to define within the pelvic nerve the projections of organ-specific sensory axons labelled by microinjection of neural tracer (cholera toxin, subunit B) into the bladder, urethra or rectum. We also examined the location of peptidergic sensory axons within the pelvic nerves to determine whether they aggregated separately from sacral preganglionic and paravertebral sympathetic postganglionic axons travelling in the same nerve. To address these aims, microscopy was performed on the major pelvic ganglion (MPG) with attached pelvic nerves, microdissected from young adult male Sprague–Dawley rats (6–8 weeks old) and processed as whole mounts for fluorescence immunohistochemistry. The pelvic nerves were typically composed of five discrete fascicles. Each fascicle contained peptidergic sensory, cholinergic preganglionic and noradrenergic postganglionic axons. Sensory axons innervating the lower urinary tract (LUT) consistently projected in specific fascicles within the pelvic nerves, whereas sensory axons innervating the rectum projected in a complementary group of fascicles. These discrete aggregations of organ-specific sensory projections could be followed along the full length of the pelvic nerves. From the junction of the pelvic nerve with the MPG, sensory axons immunoreactive for calcitonin gene-related peptide (CGRP) showed several distinct patterns of projection: some projected directly to the cavernous nerve, others projected directly across the surface of the MPG to the accessory nerves and a third class entered the MPG, encircling specific cholinergic neurons projecting to the LUT. A subpopulation of preganglionic inputs to noradrenergic MPG neurons also showed CGRP immunoreactivity. Together, these studies reveal new molecular and structural features of the pelvic nerves and suggest functional targets of sensory nerves in the MPG. These anatomical data will facilitate the design of experimental bioengineering strategies to specifically modulate each axon class.     

Prenatal development of transient receptor potential vanilloid 1-expressing primary sensory projections to sacral autonomic preganglionic neurons

The visceral reflexes of the pelvic organs are mediated by connections between primary afferents innervating the pelvic organs and parasympathetic preganglionic neurons in the intermediolateral column of the sacral spinal cord. The present immunohistochemical study revealed many varicosities expressing transient receptor potential vanilloid 1 (TRPV1) that were closely apposed to the preganglionic neuronal perikarya at embryonic day 16 in mice. Many, but not all, varicosities expressing TRPV1 in the intermediolateral column were also immunopositive for calcitonin gene-related peptide. In contrast, no nerve fibers expressing TRPV1 projected to the sympathetic preganglionic cell column in the lumbar spinal cord in prenatal stages. The results of the present study raised the possibility that the primary afferents transmit signals elicited by the activation of TRPV1 receptors to the sacral parasympathetic preganglionic neurons. Thus, the functional circuit for pelvic spinal reflexes, such as micturition induced by urine influx, might develop in the prenatal stages in mice.     

Transmitter profile and spinal inputs of pelvic ganglion cells projecting with preganglionic axons along the hypogastric and pelvic nerves of the male rat

Pelvic autonomic ganglion cells receive spinal preganglionic inputs via the hypogastric (lumbar) or pelvic (sacral) nerves. Damage to these nerves stimulates axogenesis (sprouting) from pelvic ganglion cells and two possible triggers are deafferentation (decentralisation) or, if some ganglion cells project centrally in these nerves, axotomy. We have used a combination of retrograde tracing and immunohistochemistry in male rats to identify the number of pelvic ganglion cells that project centrally along these nerves, their transmitter type and the spinal level of their preganglionic inputs. Only a small number (<1%) of pelvic ganglion cells project along these nerves; 29-65 project in each hypogastric nerve and 41-71 in each pelvic nerve. These neurons comprise of both cholinergic and noradrenergic classes and the majority receive preganglionic inputs from the nerve in which they also project. These results suggest that damage of the hypogastric and pelvic nerves close to the pelvic ganglion is unlikely to cause axotomy of many pelvic ganglion cells. Therefore deafferentation rather than axotomy is likely to be the primary trigger of axogenesis occurring in pelvic ganglia after these lesions.     

Observations on the anatomy and amine histochemistry of the nerves and ganglia which supply the pelvic viscera and on the associated chromaffin tissue in the guinea-pig

Summary The organs of the lower abdominal and pelvic regions of the guinea-pig receive nerves from the inferior mesenteric ganglia and pelvic plexuses. The inferior mesenteric ganglia connect with the sympathetic chains, the superior mesenteric ganglia, the pelvic plexuses via the hypogastric nerves, and with the gut. Each pelvic plexus consists of anterior and posterior parts which send filaments to the internal generative organs and to the rectum, internal anal sphincter and other pelvic organs. The pelvic nerves enter the posterior plexuses, which also receive rami from the sacral sympathetic chains. The adrenergic neurons of the pelvic plexuses are monopolar, do not have dendrites and are supplied by few varicose adrenergic axons. Nearly all the nerves contain adrenergic fibres. After exposure to formaldehyde vapour the chromaffin cells appear brightly fluorescent with one or two long, often varicose, processes. Most of the chromaffin cells are in Zuckerkandl's organ or in chromaffin bodies associated with the inferior mesenteric ganglia. Groups of chromaffin cells are found along the hypogastric nerves and in the pelvic plexuses; they become smaller and fewer as regions more posterior to Zuckerkandl's organ are approached.This work was supported by grants from the Australian Research Grants Committee and the National Health and Medical Research Council. We thank Professor G. Burnstock for his generous support.     

Distribution and origin of secretoneurin-immunoreactive nerves in the female rat uterus

Secretoneurin is a 33-amino acid peptide derived from secretogranin II. Secretoneurin immunoreactivity has been localized in the peripheral nervous system where it exerts potent chemotactic activity for monocytes and may play a role in inflammation. Secretoneurin could play a role in this process, although the presence and distribution of secretoneurin-immunoreactive neurons in the female reproductive system has not been documented. Thus, this study was undertaken to examine secretoneurin immunoreactivity in nerves of the rat uterus and uterine cervix. A moderate plexus of secretoneurin-immunoreactive nerve fibers was present in the myometrium and endometrium of the uterus as well as in the smooth muscle and endocervix of the cervix. Many of these fibers were associated with the vasculature as well as the myometrium. Secretoneurin immunoreactivity was present in small- to medium-sized neurons of dorsal root and nodose ganglia. Retrograde tracing with FluoroGold indicated that some of these sensory neurons project axons to the cervix and uterine horns. Secretoneurin-immunoreactive terminal-like structures were associated with neurons in the sacral parasympathetic nucleus of the lumbosacral spinal cord. In addition, some secretoneurin terminals were apposed to pelvic parasympathetic neurons in the paracervical ganglia that projected axons to the uterus and cervix. Double-immunostaining indicated co-existence of calcitonin gene-related peptide or substance P with secretoneurin in some sensory neurons, in some terminals of the pelvic ganglia, as well as nerve fibers in the uterine horn and cervix. Finally, fibers in the uterus and cervix were depleted of secretoneurin by capsaicin treatment. This study indicates that secretoneurin is present in the uterus in C-afferent nerve fibers whose cell bodies are located in sensory ganglia. Some of these fibers contain both secretoneurin and calcitonin gene-related peptide or substance P. These substances have functions in inflammatory reactions. Further, secretoneurin could influence postganglionic parasympathetic "uterine-related" neurons in the pelvic ganglia and preganglionic parasympathetic neurons in the lumbosacral spinal cord.     

Autonomic innervation of reproductive organs: analysis of the neurons whose axons project in the main penile nerve in the pelvic plexus of the rat

An understanding of the composition of the various nerves of the pelvic plexus is essential in the design of studies to explore the autonomic control of pelvic visceral tissues. As a correlate of this interest, the present study was designed to determine the composition of the main penile nerve in the pelvic plexus of the laboratory rat, an animal commonly used for studies of reproductive physiology. Retrograde tracing studies indicate that the main penile nerve contains neurons which project to the penile crura, the corpus spongiosum, and the bulbourethral glands. The main penile nerve is the major source of neurons which innervate the corpus spongiosum and bulbourethral gland and contains about one-third of all parasympathetic neurons which project to the penile crura. Dye placed on the proximal cut end of the main penile nerve indicates that neurons in the parasympathetic region of the spinal cord (L6-S1) and to a lesser extent a sympathetic region of the cord, L1-L2, provide preganglionic innervation to ganglion cells in the main pelvic nerve. Processes of neurons in dorsal root ganglia L6-S1 and of neurons in the abdominopelvic sympathetic chain course in the main penile nerve to unknown destinations. In many respects this presumed postganglionic fiber tract is essentially a region of the pelvic plexus which subserves extrapelvic visceral tissues.     

Origin of peptide-containing fibers in the inferior mesenteric ganglion of the guinea-pig: Immunohistochemical studies with antisera to substance P,enkephalin, vasoactive intestinal polypeptide,cholecystokinin and bombesin

After different denervation procedures the guinea-pig inferior mesenteric ganglion was analysed by immunohistochemistry using antisera to substance P, enkephalin, vasoactive intestinal polypeptide, cholecystokinin and bombesin. The results demonstrate that each of the nerve trunks connected to the ganglion carries specific peptidergic pathways. Thus, the lumbar splachnic nerves contain substance P-immunoreactive primary afferent neurons, which to a large extent traverse the ganglion, and enkephalin-immunoreactive preganglionic neurons; the colonie nerves carry vasoactive intestinal polypeptide-, cholecystokinin- and bombesin-immunoreactive fibers from the distal colon to the ganglion; the hypogastric nerves contain vasoactive intestinal polypeptide-positive fibers from the pelvic plexus; and the intermesenteric nerve contains vasoactive intestinal polypeptide, cholecystokinin, substance P and enkephalin from divergent sources. By studying accumulations of peptides in ligated lumbar splanchnic, intermesenteric, hypogastric and colonic nerves the existence of these major peptidergic pathways was confirmed and evidence was obtained for additional, not so prominent, peptidergic projections. The results are discussed in view of earlier morphological and physiological studies.     

Differential expression of calcium channels in sympathetic and parasympathetic preganglionic inputs to neurons in paracervical ganglia of guinea-pigs

Neurons in pelvic ganglia receive nicotinic excitatory post-synaptic potentials (EPSPs) from sacral preganglionic neurons via the pelvic nerve, lumbar preganglionic neurons via the hypogastric nerve or both. We tested the effect of a range of calcium channel antagonists on EPSPs evoked in paracervical ganglia of female guinea-pigs after pelvic or hypogastric nerve stimulation. omega-Conotoxin GVIA (CTX GVIA, 100 nM) or the novel N-type calcium channel antagonist, CTX CVID (100 nM) reduced the amplitude of EPSPs evoked after pelvic nerve stimulation by 50-75% but had no effect on EPSPs evoked by hypogastric nerve stimulation. Combined addition of CTX GVIA and CTX CVID was no more effective than either antagonist alone. EPSPs evoked by stimulating either nerve trunk were not inhibited by the P/Q calcium channel antagonist, omega-agatoxin IVA (100 nM), nor the L-type calcium channel antagonist, nifedipine (30 microM). SNX 482 (300 nM), an antagonist at some R-type calcium channels, inhibited EPSPs after hypogastric nerve stimulation by 20% but had little effect on EPSPs after pelvic nerve stimulation. Amiloride (100 microM) inhibited EPSPs after stimulation of either trunk by 40%, while nickel (100 microM) was ineffective. CTX GVIA or CTX CVID (100 nM) also slowed the rate of action potential repolarization and reduced afterhyperpolarization amplitude in paracervical neurons. Thus, release of transmitter from the terminals of sacral preganglionic neurons is largely dependent on calcium influx through N-type calcium channels, although an unknown calcium channel which is resistant to selective antagonists also contributes to release. Release of transmitter from lumbar preganglionic neurons does not require calcium entry through either conventional N-type calcium channels or the variant CTX CVID-sensitive N-type calcium channel and seems to be mediated largely by a novel calcium channel.     

Extrinsic innervation of the pelvic organs in the lesser pelvis of human embryos

Realistic models to understand the developmental appearance of the pelvic nervous system in mammals are scarce. We visualized the development of the inferior hypogastric plexus and its preganglionic connections in human embryos at 4–8 weeks post-fertilization, using Amira 3D reconstruction and Cinema 4D-remodelling software. We defined the embryonic lesser pelvis as the pelvic area caudal to both umbilical arteries and containing the hindgut. Neural crest cells (NCCs) appeared dorsolateral to the median sacral artery near vertebra S1 at ~5 weeks and had extended to vertebra S5 1 day later. Once para-arterial, NCCs either formed sympathetic ganglia or continued to migrate ventrally to the pre-arterial region, where they formed large bilateral inferior hypogastric ganglionic cell clusters (IHGCs). Unlike more cranial pre-aortic plexuses, both IHGCs did not merge because the 'pelvic pouch', a temporary caudal extension of the peritoneal cavity, interposed. Although NCCs in the sacral area started to migrate later, they reached their pre-arterial position simultaneously with the NCCs in the thoracolumbar regions. Accordingly, the superior hypogastric nerve, a caudal extension of the lumbar splanchnic nerves along the superior rectal artery, contacted the IHGCs only 1 day later than the lumbar splanchnic nerves contacted the inferior mesenteric ganglion. The superior hypogastric nerve subsequently splits to become the superior hypogastric plexus. The IHGCs had two additional sources of preganglionic innervation, of which the pelvic splanchnic nerves arrived at ~6.5 weeks and the sacral splanchnic nerves only at ~8 weeks. After all preganglionic connections had formed, separate parts of the inferior hypogastric plexus formed at the bladder neck and distal hindgut.     

An electrophysiological study of the sacral parasympathetic pathway to the colon of the cat.

1. Electrophysiological techniques were used to study the sacral parasympathetic pathway to the colon of the cat. 2. Electrical stimulation of the sacral ventral roots or the pelvic nerve elicited contractions of the colon and firing in nerve filaments on the serosal surface of the colon. Both responses were markedly reduced by the administration of ganglionic blocking agents. It is concluded that sacral preganglionic fibres to the colon make synaptic contacts with extramural ganglion cells. These cells were identified histologically in small ganglia on the serosal surface of the distal colon and rectum. 3. Transmission in extramural colonic ganglia was cholinergic and mediated by nicotinic receptors. Colonic ganglia did not exhibit large recruiting responses during repetitive (1-4 c/s) preganglionic nerve stimulation or an adrenergic inhibitory mechanism, both of which have been identified in bladder parasympathetic ganglia. It is concluded that colonic ganglia unlike bladder function primarily as simple relay stations and have little potential for modulating the neral activity arising in the central nervus system. 4. The preganglionic input to colonic ganglia was mediated by C fibres with maximal conduction velocities ranging from 0-5 to 1-4 m/sec. Bladder ganglia, on the other hand, received a preganglionic input composed of B fibres with maximal conduction velocities ranging from 8 to 10 m/sec. The possible physiological significance of different types of preganglionic fibres in the sacral outflow is discussed.     

雄性大鼠催产素纤维与脊髓泌尿生殖器调控神经元的关系

目的:观察丘脑催产素纤维与雄性大鼠脊髓泌尿生殖器调控神经元的关系。方法:微量莹光金注入雄性大鼠左侧盆腔神经节后3 d,截取脊髓胸11-骶2节段分别做横切和纵切片,观察免疫荧光组织化学显示脊髓催产素纤维和莹光金逆行示踪标记的脊髓神经元。结果:荧光金逆行示踪标记神经元位于脊髓胸12-腰2节段左侧的交感神经核﹑后灰质联合以及左侧腰6和骶1节段侧角的副交感神经核。含催产素纤维分布于荧光金标记的神经元周围。结论:丘脑催产素纤维密集分布于脊髓调控泌尿生殖器的交感和副交感节前神经元周围,这种特征性分布方式提示催产素纤维对泌尿生殖器可能有重要调节作用。     

Both synaptic and antidromic stimulation of neurons in the rat superior cervical ganglion acutely increase tyrosine hydroxylase activity

Electrical stimulation of the preganglionic cervical sympathetic trunk produces an acute increase in the rate of DOPA synthesis in the rat superior cervical ganglion. The present study was designed to test the possibility that this acute transsynaptic stimulation of catechol biosynthesis could be, at least in part, a consequence of an increase in the firing rate of the postganglionic sympathetic neurons. For this purpose, the effect of stimulation in vitro of the preganglionic cervical sympathetic trunk was compared to that of stimulation of the predominantly postganglionic internal and external carotid nerves. Stimulation of the cervical sympathetic trunk at 10 Hz for 30 min produced a 4.6-fold increase in DOPA synthesis, while simultaneous stimulation of the two postganglionic trunks produced a 3.1-fold increase. The internal carotid nerve is known to contain a small population of preganglionic fibers that synapse on principal neurons in the ganglion before entering this nerve trunk. To eliminate the possibility that the effect of stimulation of the internal carotid nerve is mediated by synaptic stimulation via these preganglionic "through fibers", the effect of stimulation of previously decentralized ganglia was examined. While decentralization reduced the magnitude of the effect of stimulation of the internal and external carotid nerves, a 2.0-fold increase in DOPA synthesis was still seen. In addition, when these nerve trunks were stimulated in control ganglia that had been maintained in organ culture for 48 h to allow time for the degeneration of afferent nerve terminals, DOPA synthesis increased 4.1-fold.(ABSTRACT TRUNCATED AT 250 WORDS)     

The origins of the adrenergic fibres which innervate the internal anal sphincter, the rectum, and other tissues of the pelvic region in the guinea-pig

Summary The adrenergic innervation of the pelvic viscera was examined by the fluorescence histochemical technique, applied to tissue from untreated guinea-pigs and from guinea-pigs in which nerve pathways had been interrupted at operation. It was found that adrenergic neurons in the inferior mesenteric ganglia give rise to axons which run in the colonic nerves and end in the myenteric and submucous plexuses and around the arteries of the distal colon. In the rectum, part of the innervation of the myenteric plexus and all of the innervation of the submucous plexus comes from the inferior mesenteric ganglia. The rest of the adrenergic innervation of the myenteric plexus comes from the posterior pelvic ganglia or the sacral sympathetic chains. The innervation of the blood vessels of the rectum is from the posterior pelvic ganglia. Adrenergic nerves run from the sacral sympathetic chains and pass via nerves accompanying the rectal arteries to the internal anal sphincter. Other adrenergic fibres to the internal anal sphincter either arise in, or pass through, the posterior pelvic plexuses. The anal accessory muscle is innervated by adrenergic axons arising in the posterior pelvic plexuses. Adrenergic nerves which run in the pudendal nerves, probably from the sacral sympathetic chains, innervate the erectile tissue of the penis.This work was supported by grants from the Australian Research Grants Committee and the National Health and Medical Research Council. We thank Professor G. Burnstock for his generous support.     

Somatostatin is present in a subpopulation of noradrenergic nerve fibres supplying the intestine

Somatostatin and dopamine β-hydroxylase have been localized in the coeliaco-mesenteric ganglia, in mesenteric nerves and in the wall of the guinea-pig small intestine. Nerve lesions were used to determine the sources of the nerves. Nerve cell bodies in the coeliaco-mesenteric ganglia with immunoreactivity for both somatostatin and dopamine β-hydroxylase project to the intestine via the mesenteric nerves. Most of their terminals are in the submucous ganglia, where they make up the full complement of noradrenergic terminals, and in the mucosa where other noradrenergic terminals, not containing somatostatin immunoreactivity, are also present. The small number of noradrenergic fibres present in the tertiary component of the myenteric plexus and in the circular muscle all show immunoreactivity for somatostatin. The noradrenergic fibres supplying the mesenteric and intestinal blood vessels and those ramifying in the myenteric ganglia do not contain somatostatin. The numerous somatostatin-immunoreactive nerves in the enteric plexuses that do not contain dopamine β-hydroxylase come from enteric nerve cell bodies.These results, considered in the context of other published work, indicate that post-ganglionic sympathetic noradrenergic neurons are chemically coded according to the target tissue they supply and suggest that neurons that were hitherto thought to be neurochemically equivalent, but which serve different functions, are in fact chemically distinct.     

Supraspinal influences on sacral autonomic nervous activity

Summary Supraspinal descending influences on the sacral parasympathetic outflow were tested recording spontaneous and reflex activity of the pelvic nerves in cats. Peripheral chemoreceptor activation enhanced the spontaneous discharge of pelvic efferents. Baroreceptor activation reduced the spontaneous activity as well as the late components of viscero- and somato-visceral reflexes. Acute spinalization (C₂) abolished the late reflex components. It enhanced the spontaneous activity and sometimes induced rhythmic discharges of the pelvic efferents.Simultaneous recording of lumbar white ramus and pelvic nerve activity suggests that the tested descending influences may act on the sacral parasympathetic preganglionic nervous activity and on the lumbar sympathetic preganglionic activity in a similar manner.This work was supported by the Deutsche Forschungsgemeinschaft.     

Facial nerve parasympathetic preganglionic afferents to the accessory otic ganglia by way of the chorda tympani nerve in the cat

 The distribution of accessory otic ganglia and connections between the ganglia and the chorda tympani nerve were investigated in the cat in order to determine the parasympathetic preganglionic facial nerve afferents to the otic ganglia using whole mount acetylthiocholinesterase (WATChE) histochemistry. The otic ganglia consist of a sigle main prominent ganglion and many small accessory ganglia lying on a plexus around the origins of the branches of the mandibular nerve and near the junction of the chorda tympani nerve and lingual nerve. In cell analysis of Nissl-stained preparations, the neurons composing the accessory otic ganglia were morphologically similar to the main otic ganglion neurons. Connecting branches from the chorda tympani nerve to the peripherally located acccessory otic ganglia were found and they were not stained by WATChE histochemistry. WATChE-positive connecting branches from the ganglia to the inferior alveolar, lingual, and mylohyoid nerves were also found in the same preparations. The WATChE histochemistry on various autonomic nervous tissues revealed that autonomic postganglionic nerve fibers are selectively stained darkly and that preganglionic fibers remain unstained. Therefore, it is considered that the WATChE-negative connections from the chordra tympani nerve consist chiefly of autonomic preganglionic fibers, whereas the WATChE-positive connections to the branches of the mandibular nerve are mainly postganglionic fibers. This suggests that some of the facial nerve parasympathetic preganglionic fibers in the chorda tympani nerve are mediated in the accessory otic ganglia and then join the branches of the mandibular nerve to supply the target mandibular tissues. Accepted: 25 November 1997     

Biosynthesis of a parkinsonism-preventing substance, 1-methyl-1,2,3,4-tetrahydroisoquinoline, is inhibited by parkinsonism-inducing compounds in rat brain mitochondrial fraction

Autonomic ganglia of the human pelvic plexus contain sympathetic and parasympathetic neurons which innervate the internal reproductive organs and the lower urinary tract while the urinary bladder also receives innervation from small intramural ganglia embedded in the detrusor muscle. Previous studies have used the immunocytochemical demonstration of tyrosine hydroxylase (TH), either alone or in combination with dopamine beta-hydroxylase, to identify noradrenergic neurons in these ganglia. However until recently a reliable marker for cholinergic neurons in the human autonomic nervous system was not available since antibodies to choline acetyltransferase do not react in this tissue. The present immunohistochemical study has used an antibody to human vesicular acetylcholine transporter (VAChT) to identify cholinergic neurons in the pelvic plexus and intramural bladder ganglia in a series of specimens from human male neonates and children. Immunostaining for TH was also carried out on the same sections and the results showed that while the vast majority of pelvic ganglion neurons were either cholinergic or noradrenergic (as seen by the presence of VAChT or TH respectively), approximately 50% of the neurons in the intramural ganglia were labeled with both immunomarkers. The presence of TH in cholinergic neurons may be due to the immaturity of the tissues examined since previous data on intramural bladder ganglia in the adult have shown that a much smaller proportion of the neurons contain TH than was observed in the present study. It is concluded that the presence of TH alone cannot be regarded as a specific marker for noradrenergic neurons in the genitourinary system of the human neonate and child.