Pelvic Ganglion Neurons Research Articles

NGF, bFGF AND CNTF increase survival of major pelvic ganglion neurons cultured from the adult rat

The responsiveness of cultured major pelvic ganglion (MPG) neurons, isolated from adult rats, to nerve growth factor (NGF), basic fibroblastic growth factor (bFGF) and ciliary neuronotrophic factor (CNTF) was tested using in vitro survival assay. MPG neurons respond to NGF with increased survival (+35 ± 13.3%, mean ± S.E.), a response completely blocked by antibodies specific to NGF. bFGF (+85 ± 9.6%) and CNTF (+10.5 ± 0.5%) also augment survival of MPG neurons in vitro. The effect of bFGF was partially blocked by bFGF antibody. Anti-NGF antibody reduced neuronal survival by 25 ± 4.1% in conditioned medium from cultures of bladder smooth muscle, suggesting bladder produces NGF. Combining antibodies against NGF and bFGF reduced survival by 19 ± 0.5% in medium supplemented with bladder extracts, suggesting the extracts contain neurotrophic activity in addition to NGF. These results support the hypothesis that neurons regulating bladder function respond to NGF and other growth factors. Therefore, previously documented changes in bladder neurotrophic factors following hypertrophy, inflammation and injury may elicit growth or change in the autonomic nervous system.

Colocalization of nitric oxide synthase and vasoactive intestinal polypeptide in single major pelvic ganglion neurons innervating the penis in the rat

Colocalization of nitric oxide synthase and vasoactive intestinal polypeptide in single major pelvic ganglion neurons innervating the penis in the rat

Effect of decentralization or contralateral ganglionectomy on obstruction-induced hypertrophy of rat urinary bladder muscle and pelvic ganglion.

After urethral obstruction the musculature of the rat urinary bladder undergoes extensive hypertrophy, irrespective of whether its innervation is intact or whether one of the two pelvic ganglia has been decentralized or excised. Even the excision of both ganglia does not inhibit muscle hypertrophy. The presence of nerves is not a prerequisite for the muscle growth to occur. The stimulus for growth resides in the bladder itself, and the present and previous observations are in agreement with the notion that the distension of the muscle is a primary stimulus for muscle growth. With bladder hypertrophy, the pelvic ganglion neurons undergo hypertrophy, even when they are devoid of their preganglionic input. Synaptic connection with the preganglionic fibres and stimuli from the spinal cord are not prerequisites for neuronal hypertrophy. However, the hypertrophy is less marked in the decentralized ganglion neurons than in the neurons of the contralateral intact ganglion. With bladder hypertrophy and contralateral ganglionectomy, the neuronal hypertrophy is greater than with either procedure alone, suggesting that the two forms of neuronal growth stimulation can be added to each other.

Hypertrophy and reversal of hypertrophy in rat pelvic ganglion neurons

An experimental procedure which chronically reduces the lumen of the urethra in adult female rats produced distension of the bladder and conspicuous thickening of its wall, resulting within 6-8 weeks in a ten-fold increase in muscle weight (muscle hypertrophy). During this process, the neurons in the pelvic ganglion that innervate the bladder undergo a large increase in size (neuronal hypertrophy). The average neuronal volume increased by 83%; small neurons became less numerous and large neurons became more numerous than in controls, but there was no increase in the maximum neuronal size. Six weeks after re-operation and removal of the urethral obstruction, the weight of the bladder was reduced (although not quite to the control levels), while the average neuronal size reversed to values very close to controls. In separate experiments, the pelvic ganglion of one side was removed. The nerve fibres in the hemidenervated bladder sprouted, grew and spread to innervate the whole bladder. The neurons in the surviving pelvic ganglion hypertrophied, the average cell volume increasing by 50% in seven weeks. The experiments showed that: (i) the pelvic neurons of adult rats are capable of very extensive growth when the tissue they innervate (bladder muscle) undergoes hypertrophy; (ii) the neuronal hypertrophy is reversible. This was taken to imply that there are factors within the bladder, including trophic substances, that regulate nerve cell volume not only by inducing growth but also by inducing the opposite effect, a cell size reduction; (iii) unilateral ganglionectomy, which did not induce muscle hypertrophy but doubled the amount of muscle innervated by the contralateral ganglion, was followed by marked neuronal hypertrophy.

Nerve growth factor responsiveness of cultured major pelvic ganglion neurons from the adult rat

The bladder and other pelvic viscera are innervated in the rat by the major pelvic ganglion (MPG), a mixed sympathetic/parasympathetic population of neurons that participates in lower urinary pathophysiology. Neurons from the MPG of adult females were removed, dissociated and cultured in order to test retention of the neuronal phenotype and whether they responded to Nerve Growth Factor (NGF). The bladder-specific subset of MPG neurons were distinguished by retrograde labeling prior to culture. The adult ganglionic neurons adapted to culture with > 80% survival in the best cases. The cultured neurons retained excitability, as determined by measuring voltage-activated ionic currents. They were positive for neuron-specific β-tubulin and many retained immunoreactivity for characteristic peptides and transmitter synthetic enzyme. The proportion of neurons in the different categories tested varied somewhat from that in vivo, but there was no evidence of selective death of a particular population. The cultured MPG neurons were responsive to NGF and anti-NGF antibody. NGF supported neuronal survival and expression of tyrosine hydroxylase. Added NGF also affected the expression of neuropeptide Y. Hypertrophied neurons from animals with experimental bladder outlet obstruction demonstrated increased responsiveness to NGF. The data suggest that NGF participates in adult neural plasticity due to continued responsiveness to the factor. Furthermore, questions concerning regulation of MPG neurons may be addressed in vitro.

Horseradish peroxidase study of the location of extrinsic efferent and afferent neurons innervating the colon of dogs

SUMMARY The abdominal portion of the colon of 13 clinically normal dogs was divided into 5 regions (ascending, transverse, left colic flexure, proximal descending, and distal descending), and each region was injected with 30 mg of horseradish peroxidase (hrp). The injected colonic region, brain stem, L7-Cd1 portion of the spinal cord, sympathetic trunk ganglia, celiacomesenteric ganglia, caudal mesenteric ganglion, pelvic plexi, distal vagal (nodose) ganglia, and Ll-Cdl spinal ganglia were obtained at postinjection hour 48, sectioned, and processed by use of the tetramethylbenzidine method. The entire length of the colon was found to be under extrinsic influence of the parasympathetic nucleus of cranial nerve X (px), with the largest average number of labeled cells resulting from injection of the ascending colon. It was also indicated that the entire colon is under extrinsic influence of the sacral portion of the spinal cord because the pelvic ganglia (second-order neurons) of the pelvic plexi contained labeled cells for all colonic regions. The largest average number of labeled cells in pelvic ganglia was seen after injection of the distal portion of the descending colon. Only after injection of the distal portion of the descending colon were labeled cells found in the S1-S3 portion of the spinal cord. Labeled cells in the px, spinal cord, and pelvic ganglia were found bilaterally. Although the entire abdominal portion of the colon appears to be influenced by cranial and sacral parasympathetic preganglionic (via pelvic ganglia) neurons, the relative importance of the 2 areas seems to be reversed between the ascending colon and distal portion of the descending colon. Sympathetic postganglionic innervation was located in the celiacomesenteric ganglion, caudal mesenteric ganglion, and, inconsistently, in sympathetic trunk ganglia. Sensory innervation for all colonic regions was found bilaterally in the distal vagal ganglia, and in 2 groups of spinal ganglia—a cranial group of LI to L5 and a caudal group of S1 to Cd1 ganglia. It has been reported in the literature that the left colic flexure is subject to colonic perforation in dogs with spinal cord disease treated with corticosteroid administration, but a direct, anatomic reason for this site of susceptibility was not found during this study. It is possible that the left colonic flexure represents the most proximal portion of colon detrimentally affected by loss of sacral influence, because the relative importance of vagal and sacral parasympathetic innervation appears to shift along the length of the colon.

Properties of voltage-dependent barium currents in neurons of pelvic parasympathetic ganglia of rabbit.

Properties of voltage-dependent barium current (IBa) were examined in parasympathetic neurons of the rabbit urinary bladder, in vitro. Transient low-threshold IBa was evoked by voltage jump from a holding potential (Vh) of -100 to -50 mV. Additional transient high-threshold IBa appeared at potentials more positive than -30 mV. Long-lasting high-threshold IBa was evoked at 0 to -20 mV. High-threshold currents were blocked by omega-conotoxin but not by dihydropyridines.

Immunohistochemical characterization of pelvic neurons which project to the bladder, colon, or penis in rats

Retrograde-tracing and immunohistochemical techniques were used in combination to investigate the types of putative transmitters in pelvic neurons that project to the bladder, colon or penis of rats. In addition, populations of axon varicosities associated with these neurons were characterized. Subpopulations of neurons in colchicine-treated major pelvic ganglia and accessory ganglia of male rats contained immunoreactivity (IR) for tyrosine hydroxylase (TH), vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), or enkephalin (ENK), while types of immunoreactivity found in major groups of varicose axons were ENK, cholecystokinin (CCK), and somatostatin (SOM). Substance P (SP)-IR varicose axons were much less common. Bladder and colon neurons were similar in a number of ways. Many neurons contained NPY-IR (greater than or equal to 50%), fewer contained TH-IR (25-30%), and even fewer contained ENK-IR (5-15%) or VIP-IR (5-10%); many neurons were associated with baskets of ENK-IR varicosities (50-65%) and fewer neurons were surrounded by CCK- or SOM-IR varicosities (30-35%). Colon neurons differed from penis neurons in having a slightly larger proportion that contained ENK-IR (10-15%, compared with 1-3%). Penis neurons were markedly different from the other two groups in additional ways. More than 90% of them contained VIP-IR, whereas only 5-7% contained NPY-IR and none were immunoreactive for TH. Furthermore, although the proportion of penile neurons associated with many ENK-IR varicosities was similar to the bladder and colon neurons (45-50%), they were rarely seen close to CCK- or SOM-IR varicose axons. These studies describe similarities and differences in the histochemical properties of neurons which project to the bladder, colon, or penis and of the varicose axons associated with those neurons. This gives further insights into the possible transmitter mechanisms involved in the regulation of different pelvic functions.

Frequency dependent inhibition of the nicotinic transmission by serotonin in vesical pelvic ganglia of the rabbit

Intracellular recordings were made from neurons in rabbit vesical pelvic ganglia (VPG), in vitro. Increasing the frequency of preganglionic-nerve stimulations from 0.1–1 Hz to 10–20 Hz facilitated fast excitatory postsynaptic potentials (EPSPs), resulting in a generation of action potentials. Acetylcholine-induced response was not altered during the facilitation of the fast EPSP. Serotonin blocked action potentials elicited by preganglionic-nerve stimulations at 0.1 Hz, while it caused no blockade at 10 Hz. Serotonin may potentiate the feature of high-pass filter [1] in transmission of VPG. Immunohistochemical study demonstrated serotonin-like varicose terminals in rabbit VPG.

5-Hydroxytryptamine produces presynaptic facilitation of cholinergic transmission in rabbit parasympathetic ganglia

Intracellular recordings were made from neurons of rabbit vesical pelvic (parasympathetic) ganglia (VPG). Application of 5-hydroxytryptamine (5-HT, 0.3–30 μM) produced an initial depression followed by a long-lasting facilitation of the fast excitatory postsynaptic potential (e.p.s.p.) evoked by stimulation of the pelvic preganglionic nerve. The facilitation of nicotinic transmission lasted for 30–120 min, even when 5-HT was removed from the superfusing solution. 5-HT (0.3–30 μM) did not change the depolarization induced by a direct application of acetylcholine (ACh) to the VPG neurons pretreated with 1 μM atropine. 5-HT also caused an initial depression followed by an increase in the quantal content of the fast e.p.s.p. It is, therefore, suggested that diphasic effect of 5-HT on the nicotinic transmission is due mainly to a modulation of the ACh-release from presynaptic nerve terminals. Methysergide (5 μM), mianserin (5–30 μM) and ICS 205–930 (100–300 nM) did not antagonize the presynaptic actions of 5-HT on the nicotinic transmission, suggesting that the presynaptic 5-HT receptor may belong to a class of 5-HT 1 subtypes. Spiperone (1 μM), a selective 5-HT 1A antagonist, blocked the 5-HT-induced inhibition of the fast e.p.s.p. Under the effect of spiperone, the facilitation appeared soon after application of 5-HT. The facilitation of the fast e.p.s.p. may be mediated through a 5-HT 1B or 5-HT 1C subtype. Lowering temperature of the external solution eliminated the 5-HT-induced facilitation of the nicotinic transmission. Forskolin produced a presynaptic facilitation of the fast e.p.s.p., without producing an initial depression. 3-Isobutyl-1-methylxanthine (10 μM) potentiated the facilitatory action of 5-HT. Bath-application of dibutyryl cyclic adenosine monophosphate (cAMP) (1–6 mM) and 8-bromo-cyclic AMP (2–5 mM) mimicked the effect of 5-HT in producing the facilitation of the fast e.p.s.p.s. All data presented are consistent with the hypothesis that 5-HT, acting on presynaptic 5-HT 1 receptors, causes a facilitation in the release of ACh from preganglionic nerve terminals possibly mediated through an activation of adenylate cyclase.

Calcium-dependent potassium conductance in neurons of rabbit vesical pelvic ganglia

Intracellular recordings were made from neurons of vesical pelvic (parasympathetic) ganglia (VPG) isolated from the rabbit urinary bladder. Spontaneous hyperpolarizations (SH), occurring at intervals of 30 s to 5 min, could be recorded from 53% of VPG neurons in Krebs solution. The action potential was associated with inward sodium and calcium currents and was followed by fast and slow afterhyperpolarizations (AHPs). The action potential also evoked an additional hyperpolarization which was identical to the SH. The SH and the AHPs were associated with a decrease in the input resistance and reversed their polarity close to the potassium equilibrium potential. Intracellular cesium ions blocked the AHPs and the SH. Superfusing the preparation with a calcium-free solution produced a depolarization associated with an increased input resistance. The outward rectification activated at the resting membrane potential was depressed in the calcium-free solution. The removal of extracellular calcium ions also depressed both the SH and the spike AHPs. Bath-application of caffeine (1–3 mM) increased the frequency of the appearance of the SH. Injection of EGTA into VPG neurons caused a depolarization due to a blockade of the outward rectification. EGTA also depressed the slow AHP and the SH. These results suggest that the neuronal membrane of the rabbit VPG is endowed with a calcium-dependent potassium conductance ( gK Ca). Apamin (0.3–5 nM) and (+)-tubocurarine (30–300 μM) blocked the slow AHP and the SH without affecting the fast AHP and the resting membrane potential. Tetraethylammonium (TEA, 0.3–5 mM) suppressed the fast AHP and the SH without affecting the outward rectification. TEA augmented the slow AHP. Barium ions (0.1–1 mM) depressed the AHPs, the SH and the outward rectification. These pharmacological properties imply that at least 3 kinds of gK Ca systems underlie the generation of the outward rectification, the spike AHPs and the SH.

5-Hydroxytryptamine inhibits cholinergic transmission through 5-HT 1A receptor subtypes in rabbit vesical parasympathetic ganglia

Intracellular recordings were made from parasympathetic neurons of the rabbit vesical pelvic ganglia (VPG) maintained in vitro. 5-Hydroxytryptamine (5-HT) inhibited cholinergic transmission in the VPG by reducing the fast excitatory postsynaptic potential (EPSP) evoked by stimulations of pelvic nerves. 8-Hydroxy-2-(di- n-propyl-amino) tetralin hydrochloride mimicked the inhibitory effect of 5-HT on the ganglionic transmission. 5-HT-induced inhibition of the fast EPSP was antagonized by spiperone. The results suggest that 5-HT 1A receptor subtypes mediate the inhibition of cholinergic transmission in the rabbit VPG.

Selective facilitatory effect of vasoactive intestinal polypeptide (VIP) on muscarinic firing in vesical ganglia of the cat

VIP immunoreactivity was identified in nerve fibers and in 10–13% of the neurons in pelvic and bladder ganglia of the cat. Ninety percent of the VIP positive neurons contained acetylcholinesterase. VIP immunoreactivity was not altered in decentralized ganglia 1 week to 8 months after transection of the pelvic and hypogastric nerves indicating that VIP fibers arose from neurons within the peripheral nervous system. The intra-arterial administration of VIP (1–50 μg/kg) enhanced the postganglionic discharge elicited by the muscarinic agonist, acetyl-ß-methylcholine, but did not alter the postganglionic firing elicited by the nicotinic agonist, tetramethylammonium or by electrical stimulation of preganglionic axons in the pelvic nerve. VIP did not elicit a postganglionic discharge in untreated ganglia, but did evoke a prolonged discharge in ganglia treated with an irreversible anticholinesterase agent, 217AO. This discharge was not affected by hexamethonium but was blocked by atropine. VIP suppressed the muscarinic inhibition of ganglionic transmission produced by acetyl-ß-methylcholine without altering the response to other inhibitory agents (norepinephrine, leucine-enkephalin and γ-aminobutyric acid (GABA). VIP (0.1–0.3 μg/kg) also had a direct inhibitory effect on bladder smooth muscle. These findings raise the possibility that intraganglionic pathways containing VIP may exert a selective modulatory influence on muscarinic transmission in vesical parasympathetic ganglia.

Nerve growth factor.

Nerve growth factor.