Adrenergic and cholinergic innervation of the rag urinary bladder

Multiple tachykinin binding sites in hamster, rat and guinea-pig urinary bladder

Binding of the 125I-Bolton-Hunter labelled tachykinins substance P, substance K, eledoisin and neuromedin K (BHSP, BHSK, BHE, BHNK) was examined in urinary bladders of hamster, rat and guinea-pig using crude membrane suspensions and by autoradiography. High-affinity binding of BHSK was observed in hamster and rat bladder and high-affinity binding of BHSP was seen in rat and guinea-pig bladder. Characterization of this binding showed that the hamster bladder contains very large numbers of K-type binding sites, where BHSK is displaced by substance K greater than kassinin greater than eledoisin greater than neuromedin K greater than substance P greater than physalaemin, and has very few P-type binding sites, where BHSP is displaced by substance P greater than substance K much greater than neuromedin K. In contrast, the rat bladder contains moderate and approximately equal numbers of both K (KD, 0.74 nM; Bmax 2.9 fmol/mg wet weight tissue) and P (KD, 0.12 +/- 0.01 nM; Bmax 2.6 +/- 0.2 fmol/mg wet weight tissue) sites. The guinea-pig bladder possesses predominantly P sites. Most tachykinin binding sites are localized over smooth muscle and probably represent functional receptors mediating the direct contractile effects of tachykinins in these tissues. Few E-type binding sites, as previously described in rat brain, were found, although some BHNK binding sites were seen in the mucosa of guinea-pig bladder.

An atropine-like inhibitory effect of DMPP on rat isolated urinary bladder

DMPP inhibits the nerve-mediated contractions of the rat isolated bladder, its effect being greater in preparations from newborn (2 day old) than adult animals. This effect of DMPP was unaffected by hexamethonium. In preparations from adult animals the effect of DMPP increased with frequency of stimulation and was fully prevented by the presence of atropine. In bladders from newborn rats low concentrations of furthrethonium (FHR) (10 nM) activated a series of rhythmic contractions which were unaffected by tetrodotoxin and abolished by DMPP through an hexamethonium-insensitive action. On the other hand DMPP did not affect rhythmic contractions produced by a low concentration of eledoisin (60 nM). In bladders from adult rats FHR (10 microM) and KCI (30 mM) produced contractures of comparable magnitude. DMPP inhibited, in concentration-related manner the FHR-induced tonic contraction but had little effect on that produced by KCI. These findings indicate that in the rat bladder, DMPP antagonizes selectivity cholinergically-mediated contractions through a mechanism which is unaffected by hexamethonium or tetrodotoxin. An "atropine-like' activity of DMPP should be considered.

Intramural neurons of the guinea-pig urinary bladder: histochemical localization of putative neurotransmitters in cultures and newborn animals

Histochemical methods have been used to study the distribution of putative neurotransmitters in the urinary bladder of newborn guinea-pigs and in cultures of intramural ganglia. Following the nicotinamide adenine dinucleotide (NADH)-diaphorase reaction which specifically labels nerve cell bodies, up to 66 ganglia were observed in stretch preparations of the newborn urinary bladder. Each ganglion contained 2-50 nerve cell bodies. Vasoactive intestinal polypeptide was localized in a few nerve cell bodies of intramural ganglia both in in situ and culture preparations. In the in situ preparations it was widely distributed in nerve fibres to the muscle, being most dense at the base of the bladder, and in some mucosal epithelial cells. Somatostatin was contained in numerous neuronal cell bodies in the detrusor muscle both in situ and in culture. Extensively distributed varicose fibres were found in culture and in the muscle, submucous and mucosal layers in situ. Substance P immunofluorescence was demonstrated in a few neuronal cell bodies in ganglia both in situ and in vitro, particularly in those of the mucosa at the base of the bladder. In the in situ preparations varicose nerve fibres containing substance P were seen in the muscle coats with greatest density in the bladder base. Met-enkephalin-immunoreactive nerve cell bodies were not seen either in situ or in culture. Nerve fibres in in situ preparations were found largely enveloping neuronal cell bodies within the ganglia. Neither serotonin-immunoreactive nor catecholamine-containing neuronal cell bodies were seen in the in situ bladder preparation. However, some nerve cell bodies in culture showed positive staining, possibly as a result of selective uptake of serotonin and catecholamine known to be contained in foetal calf serum in the culture medium or possibly as the result of increased synthetic activity in certain neurones in the culture situation. In whole-mount stretch preparations, no serotonin-immunoreactive nerve fibres were seen, but catecholamine-containing small intensely fluorescent cells and nerve fibres were observed. Acetylcholinesterase-positive nerve cell bodies and nerve fibres were observed both in in situ and culture preparations of the bladder. Quinacrine-positive nerve cell bodies (as an indicator of purinergic neurones) were found in numerous intramural neurones examined. in situ; however, under the culture conditions used, non-selective staining of all cell types occurred.

Composition of the pelvic nerve

Surgical interruption of the pelvic nerve elevated immunoreactive vasoactive intestinal polypeptide in the major pelvic ganglion of the rat. Two changes were noted: (i) varicose and smooth fibers appeared in the neuropil and (ii) a small number of ganglion cells became highly reactive for the polypeptide. A more proximal transection of preganglionic parasympathetic fibers, at their origin from spinal nerves, had no effect on vasoactive intestinal polypeptide immunoreactivity. Ganglion cells were labeled when a dye was applied to the cut distal end of the pelvic nerve. We conclude that a population of vasoactive intestinal polypeptide-containing neurons in the major pelvic ganglion send their axons proximally in the pelvic nerve.

The role of the capsaicin-sensitive innervation of the rat urinary bladder in the activation of micturition reflex

Capsaicin applied on the serosal surface of the urinary bladder in urethane-anaesthetized rats produces two distinct types of motor effects: a tetrodotoxin-, hexamethonium- and lidocaine-insensitive 'tonic' contraction and a series of tetrodotoxin-, hexamethonium- and lidocaine-sensitive rhythmic contractions. Both 'tonic' and rhythmic contractions are abolished by bladder denervation indicating their neurogenic origin. The rhythmic but not the 'tonic' component of the contractile effect of capsaicin is abolished by spinal cord transection indicating activation of a supraspinal micturition reflex. The motor effects of topical capsaicin are unaffected by pretreatment with indomethacin or diphenhydramine plus cimetidine. Pretreatment with a large dose of subcutaneous (SC) capsaicin increases both volume and pressure threshold for micturition while amplitude of micturition contraction is unaffected. Moreover the spinal somatovesical reflex elicited by pinching of the perineal skin is unaffected by capsaicin-desensitization. The intracerebroventricular (ICV) administration of capsaicin reproduces the effects of SC capsaicin on the bladder response to saline filling. Rats pretreated with ICV capsaicin are as sensitive as controls in reacting to noxious heat (hot plate test) while the wiping response to instillation of capsaicin into one eye was abolished. These findings provide functional evidence for the presence in the rat urinary bladder of a capsaicin-sensitive innervation which subserves a sensory function in relaying volume/pressure information from detrusor muscle to central nervous system. Information carried through these capsaicin-sensitive fibers appears to be relevant for initiation of a supraspinal vesico-vesical micturition reflex. Functional evidence indicates that these fibers may terminate at supraspinal level.

Innervation of the child urinary bladder

Muscle strips from the fundus, trigonum and distal ureters obtained from children at operations for vesico-ureteric reflux were studied using histochemical and immunohistochemical methods, and electrical nerve stimulation in an organ bath. A rich supply of cholinergic nerves was found and despite a partial atropine resistance the neurophysiological experiments indicated that the transmitter causing contraction of the detrusor muscle is acetylcholine. Imipramine, which is used in the treatment of enuresis, had no anticholinergic effect on the bladder in the doses used clinically. The adrenergic innervation was very sparse except around the ureter orifices. No contractile alpha-adrenoceptors could be detected but beta receptor mediated relaxation was found, which was neither of the beta 1 nor beta 2 type. A third type of beta receptor is postulated. Peptidergic nerves containing vasoactive intestinal peptide, VIP, were demonstrated in a few nerve terminals running along bundles of smooth muscle. No nerves containing enkephaline, somatostatine or substance P were found. VIP affected the detrusor muscle indicating a possible role as a modulator of transmitter action, while substance P had no effect. The anticholinergic and calcium antagonistic drug terodiline inhibited all muscle activity, whether it was induced by nerve stimulation, cholinergic drugs or a potassium rich solution, making it suitable for treatment of diurnal enuresis.

The neural and non-neural mechanisms involved in urethral activity in rabbits

The effects of electrical and chemical stimulation on the mechanical or electrical properties of the circular smooth muscle cells of the bladder neck, and proximal urethra of the male rabbit were investigated by means of micro-electrode, double-sucrose-gap and tension-recording methods. In the bladder neck, application of short current pulses (50 microseconds) produced an initial excitatory junction potential (e.j.p.) with a superimposed spike, followed by a late depolarization, and these electrical events evoked contraction. The initial e.j.p. was unaffected by guanethidine, phentolamine, methysergide or mepyramine, indicating the initial e.j.p. is not mediated by activation of adrenergic, tryptaminergic or histaminergic receptors. The late depolarization was enhanced by pre-treatment with neostigmine (10(-7) M) and abolished by atropine (10(-6) M). In the proximal urethra, electrical-field stimulation evoked phasic contraction which was followed by relaxation, associated with initial e.j.p.s, late depolarization and inhibitory junction potentials (i.j.p.s). Guanethidine (10(-5) M) or phentolamine (10(-6) M) reduced the size of the initial e.j.p. to 40-50% of the control value and combined application of guanethidine and atropine further reduced the amplitude of the e.j.p. to 20-30%. There was a parallel reduction in the mechanical response. The late depolarization was enhanced by neostigmine and abolished by atropine. The i.j.p. and muscle relaxation were not affected by propranolol, phentolamine, guanethidine or atropine. These results indicate that the proximal urethral smooth muscle cells are innervated by adrenergic and cholinergic excitatory, and by non-cholinergic non-adrenergic inhibitory nerve fibres. In the prostatic urethra, field stimulations also evoked twitch contractions with or without following phasic contraction and relaxation. The twitch contractions were abolished by d-tubocurarine (10(-6) M), suggesting that they arise from striated muscle. Exogenously applied prostaglandin (PG) E1, PGE2 or PGF2 alpha (greater than 10(-10) M) evoked sustained increase in the muscle tone in the presence or absence of indomethacin, and enhanced the amplitude of muscle relaxation evoked by the field stimulation without affecting the resting membrane potential. Indomethacin (10(-6)-10(-5) M) gradually reduced the muscle tone of the proximal urethra with no change in the resting membrane potential. At the reduced muscle tone, electrical-field stimulation did not evoke muscle relaxation. Thus, the amplitude of muscle relaxation evoked by field stimulation was dependent on the level of muscle tone of the circular muscle strips.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of cholinoreceptors in the rat urinary bladder by the use of agonists and antagonists of the cholinergic system

The effects of stimulatory and inhibitory compounds acting on both nicotinic and muscarinic receptors have been evaluated in the isolated urinary bladder from adult and immature (14-18 days old) rats. Acetylcholine and bethanechol were found to induce concentration-dependent contractions which were inhibited by atropine and pirenzepine; compound McN-A-343 had a negligible contractile activity whereas DMPP had no effect at all. Responses to electrical field stimulation were abolished by tetrodotoxin (3 X 10(-8) M), enhanced by eserine (10(-8) M) and scarcely affected by hexamethonium (10(-3) M), trimethaphan (10(-3) M) and d-tubocurarine (10(-3) M). Atropine, pirenzepine and DMPP induced only a partial inhibition (50%) of the twitch response, whereas compound McN-A-343 caused a concentration-dependent inhibitory effect which was maximum (100% inhibition) at 10(-2) M. No significant differences were found between results obtained in immature and adult animals as regards either the stimulatory or the inhibitory compounds tested. It was concluded that postjunctional muscarinic receptors were responsible for the stimulatory responses observed, whereas an additional involvement of unknown mechanisms, probably not related to the cholinergic system, was suggested by the peculiar results obtained with DMPP and compound McN-A-343 on electrically-stimulated urinary bladder. Whatever the mechanisms involved, however, they are already present at the first stage of postnatal development.

Calcitonin gene-related peptide (CGRP) in the female rat urogenital tract

CGRP-immunoreactivity was found throughout the female rat urogenital tract by specific radioimmunoassay, and shown to be present in nerve fibres by immunocytochemistry. The highest concentrations of CGRP-like immunoreactivity were found in the urinary tract, with lower levels in regions of the genitalia. Chromatographic analysis of bladder and vaginal extracts on Sephadex G-50 columns and HPLC revealed at least three CGRP-immunoreactive peaks. The major peak emerged in the same position as synthetic rat CGRP. CGRP nerve fibres were associated mainly with blood vessels, non-vascular smooth muscle, squamous epithelium and uterine and cervical glands, and were particularly abundant in the ureter and bladder. CGRP-immunoreactivity was depleted by neonatal treatment with capsaicin and after surgical section of pelvic and/or hypogastric nerves. Immunocytochemistry demonstrated that depletion occurred predominantly in the mucosal layer of the urogenital tract. These findings indicate a sensory function for most of the CGRP-immunoreactive nerves in the rat urogenital tract.

Pharmacological evidence for the existence of two components in the twitch response to field stimulation of detrusor strips from the rat urinary bladder

Isolated strips from the anterior dome of the rat urinary bladder respond to single pulse field stimulation with a contraction. Two distinct components of this contraction ("early' and "late') could be observed, both of which were unaffected by hexamethonium (10 microM) and almost abolished by tetrodotoxin (1 microM) indicating their dependence on neurotransmitter release from postganglionic nerve endings. Atropine (3 microM) inhibited the "late' component (over 60%) to a significantly greater extent than the "early' component (less than 10%) Amplitude of the "early' component was usually greater than that of the "late' component. There was almost no difference between the "early' and "late' component in respect of their relationship to stimulus strength and pulse duration. Physostigmine (0.03 microM) enhanced both components of the nerve-mediated contraction, although enhancement of the "late' component was much greater than that of the "early' one. Tetraethylammonium (TEA, 0.5-5 mM) enhanced, in a concentration-related manner, both "early' and "late' components of the nerve-mediated contraction. Following exposure to physostigmine or TEA (5 mM) both "early' and "late' components of contraction were almost completely inhibited by tetrodotoxin. Atropine inhibition was more evident on the "late' as compared to "early' component of contraction. These findings demonstrate the presence, in the twitch response of rat isolated urinary bladder to field stimulation, of two nerve-mediated components which exhibit a different susceptibility to atropine and physostigmine.

Origin and distribution of neuropeptide Y-, vasoactive intestinal polypeptide-and substance P-containing nerve fibers in the urinary bladder of the rat

The origin and distribution in the urinary bladder of nerve fibers containing neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and substance P (SP) were investigated in rats. Experimental procedures comprised preganglionic decentralization or postganglionic denervation of the bladder and also chemical sympathectomy as well as capsaicin treatment of newborn rats. Nerve fibers containing NPY were richly distributed in the detrusor muscle and also in the pelvic ganglia. Numerous NPY-containing nerve cell bodies were found in pelvic ganglia. A rich occurrence of VIP fibers and a more sparse distribution of SP-containing fibers were also found in the bladder as well as a relatively rich representation of VIP-containing nerve cell bodies in the pelvic ganglia. After decentralization the intensity of VIP and NPY immunofluorescence increased in nerve cell bodies of the pelvic ganglia and in nerve fibers in the wall of the bladder. Postganglionic denervation, on the other hand, eliminated all peptides examined in the bladder wall. After postganglionic denervation the situation in the ganglia was approximately the same as after decentralization. Chemical sympathectomy (6-OHDA) did not seem to change significantly the frequency and distribution of VIP-, SP- and NPY-fibers in the muscle layer of the bladder or in the pelvic ganglia, while the NPY-containing nerve fibers in the submucosal layer and around blood vessels of the bladder disappeared. Adrenergic nerve fibers in the wall of the bladder (visualized by histofluorescence) were markedly reduced in number after administration of 6-OHDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Efferent sympathetic nervous control of rectal motility in the cat

The sympathetic nervous control of rectal motility was studied in anesthetized cats. Division of the sympathetic nerves, i.e. the hypogastric nerves and the lumbar colonic nerves and alpha-adrenergic blockade reduced rectal tone indicating that these nerves are tonically active. Efferent electrical stimulation of the nerves at high intensities caused an immediate and sustained contraction which was inhibited after phentolamine but unaffected by hexamethonium suggesting a direct alpha-adrenergic effect on the rectal smooth muscle. However when prevailing rectal tone was high beta-adrenergic inhibitory responses unaffected by hexamethonium were observed. In addition the hypogastric nerves seem to convey cholinergic excitatory fibres to the rectum. The results imply that the sympathetic nerves are integrated in the nervous regulation of rectal motility in a fashion similar to the nervous control of the internal anal sphincter.

A novel non-adrenergic, non-cholinergic nerve-mediated relaxation of the pig bladder neck: an examination of possible neurotransmitter candidates

Electrical field stimulation of the isolated pig bladder neck preparation initiated rapid non-adrenergic, non-cholinergic nerve-mediated relaxations. A wide range of substances were examined as possible candidates for the neurotransmitter involved. Of these, only 5-hydroxytryptamine, vasoactive intestinal polypeptide, adenosine and adenosine 5'-triphosphate produced relaxations. Noradrenaline, acetylcholine, substance P, bradykinin and angiotensin II caused contraction, while neurotensin, somatostatin, bombesin and gamma-amino butyric acid were without effect. The nerve response was not blocked by methysergide, ketanserin, chymotrypsin, apamin or 8-phenyltheophylline, although methysergide antagonised the responses to 5-hydroxytryptamine, chymotrypsin blocked the responses to VIP, and 8-phenyltheophylline antagonised the responses to adenosine and ATP.

On a cholinergic motor innervation of the rat urethra

Choline acetyltransferase activity was demonstrated in the proximal part of the male rat urethra, indicating a cholinergic innervation of this tissue. The cholinergic nerve fibres emanated evidently from the pelvic nerves, since bilateral removal of the pelvic ganglion caused a major fall in the activity of this enzyme. The muscle activity of the circular layer of the proximal urethra was recorded in vitro. The basal activity of this segment was low. The parasympathomimetics acetylcholine and methacholine, evoked rapid and marked contractile responses; the maximal responses to these drugs were 36 and 44%, respectively, of that to potassium. The corresponding figures for phenylephrine and noradrenaline were found to be 79 and 88%, respectively. The responses evoked by the parasympathomimetics were unaffected by the ganglion blocker hexamethonium, the alpha-adrenoceptor blocker dihydroergotamine and the beta-adrenoceptor blocker propranolol. Atropine, however, abolished the responses completely. Following degeneration of adrenergic or cholinergic nerves of the urethra the parasympathomimetics still evoked contractions. Taken together these findings indicate that the parasympathomimetics exert their contractile effect through a direct action on muscarinic receptors. Parasympathectomy but not sympathectomy (caused by 6-hydroxydopamine treatment) gave rise to a supersensitivity to methacholine, as judged by a leftward shift of the dose-response curve for this drug, the ED50-value being ten times less than that of the controls. The observations seem to suggest that the proximal urethra normally is under the influence of cholinergic activity beside that of adrenergic activity previously demonstrated.

Rat bladder in the early stages of streptozotocin-induced diabetes: adrenergic and cholinergic innervation

The adrenergic and cholinergic innervation of the bladder was studied in streptozotocin-diabetic rats. The presence of hypertrophy and distension in the 'diabetic' bladders necessitates care in assessing changes occurring in the nerves, factors which are also relevant to clinical histochemical studies. Biochemical assays of cholinergic enzymes revealed decreased activities per g wet weight tissue. However, the total activities of choline acetyltransferase and acetylcholinesterase per whole bladder were significantly increased after 2 weeks of diabetes with greater changes by 8 weeks. Total dopamine levels per bladder were significantly higher than in control rats in the 2-week but not the 8-week group of animals; this may indicate an initial increase in adrenergic nerve activity. There was no impairment in the ability of the detrusor muscle to respond to noradrenaline, acetylcholine or to cholinergic nerve stimulation. Shortly after induction of diabetes streptozotocin-treated rats display polyuria. It is proposed that the activity of the bladder is therefore stimulated to allow greater volumes of urine to be passed. The results are discussed in relation to human diabetes mellitus where clinical studies have implicated a neuropathic origin to bladder dysfunction.

Inhibitory effect of alpha-alpha-diphenyl-alpha-propoxyacetic acid-L-methyl-4-piperidyl ester hydrochloride on the activity of the rat urinary bladder

alpha-alpha- Diphenyl-alpha- propoxyacetic acid-l-methyl-4-piperidyl ester hydrochloride(propiverine) significantly decreased the volume-pressure ratio of the rat urinary bladder and suppressed efferent nervous activity of the bladder branch of the pelvic nerve during vesical extension.

Sensory substance P-innervation of the urinary bladder: possible site of action of capsaicin in causing urine retention in rats

In rats treated neonatally with capsaicin there is, in later life, a tendency tendency towards urine retention. Since capsaicin is known to cause irreversible loss of certain primary sensory neurons, notably those containing substance P, we have studied the sensory innervation of the bladder in capsaicin-treated and control rats using retrograde tracing methods and immunohistochemistry; in addition, the motor function of the bladder was assessed in in vitro experiments, using electrical field stimulation. Five days after injection of the fluorescent tracer True Blue into the wall of the bladder, numerous labelled cells were identified in dorsal root ganglia T13, L1, L2, L6, and S1 and smaller numbers of cells were found in T12 and L3. In capsaicin-treated rats the numbers of labelled cells were reduced by over 50% in L1, L6 and S1. In control rats, 10-16% of True Blue labelled cells also contained substance P as demonstrated by indirect immunofluorescence, but in capsaicin-treated rats substance P cells were virtually absent. In in vitro studies, contractions of the detrusor muscle to electrical field stimulation, both before and after atropine, were similar in control and capsaicin-treated rats. We suggest that capsaicin causes urine retention in rats due to an impairment of sensory transmission from the bladder (that could involve substance P) and a consequent failure in the normal micturition reflexes.

Supersensitivity in the isolated urethra of the rat following "chemical sympathectomy"

The circular muscle activity of the urethra of the male rat was isometrically measured in vitro in response to noradrenaline, phenylephrine and isoprenaline. The urethra was found to be supplied with both alpha- and beta-adrenoceptors mediating contraction and relaxation, respectively. The substance 6-hydroxydopamine is known to cause a selective destruction of adrenergic nerves. In the present study 6-hydroxydopamine (100 mg/kg) was injected intravenously into a group of rats twice with a weekly interval. When the urethra was examined 2-3 weeks after the first injection a supersensitivity mediated both via alpha- and beta-adrenoceptors was found to have developed, suggesting that the urethra of the male rat normally is under the influence of adrenergic activity. The findings are discussed in relation to denervation supersensitivity of the neurogenic bladder in man.

Length-tension relations of smooth muscle from normal and denervated rat urinary bladders

Urinary bladders of rats were denervated by bilateral excision of the pelvic ganglion and removed 10 days after the operation. They were filled with 0.75 ml saline and a longitudinal muscle strip was marked out, measured and dissected out. Strips from normal bladders filled with the same volume were used as controls. Denervated bladders were 4-5 times heavier than control bladders. Muscle strips from denervated bladders showed, in contrast to controls, marked phasic spontaneous contractions which were unaffected by tetrodotoxin, indicating a myogenic origin. Active tension in response to AC stimulation was measured at different lengths. In relation to the in situ length (Lin situ) at 0.75 ml the denervated strips had to be stretched to much greater extent than controls in order to reach optimum length (L0) for force development. Furthermore, the denervated strips shortened less in relation to Lin situ than the controls. If active length-tension relations were expressed in relation to L0, the difference between denervated and control strips was abolished. Maximal active force was the same for denervated and control strips. Water content increased significantly in denervated bladders. The results suggest a remodelling of the smooth muscle structure in denervated bladders; the characteristics of the contractile machinery seem, however, to be unaltered.

Outgrowth of cholinergic nerves in the rat urinary bladder either partially denervated or partially denervated and decentralized

Unilateral excision of the pelvic ganglion caused a loss in the number of AChE-positive nerves in the rat urinary bladder both on the operated side and on the contralateral side, thus indicating a bilateral intramural distribution of cholinergic nerves derived from the pelvic nerve. In the course of the subsequent observation period (3-28 days) the AChE-positive nerves increased in number and in staining intensity and further, the nerves became ramified and twisted. Similar events were found to occur in the urinary bladder decentralized on one side and denervated on the other. The morphological findings indicate an outgrowth of cholinergic nerves by collateral sprouting. These findings are discussed in relation to previous physiological studies.

Increase in choline acetyltransferase activity in surgically isolated postganglionic parasympathetic neurones of the urinary bladder of adult rats

In the urinary bladder of adult male rats the choline acetyltransferase activity in postganglionic neurones isolated from the central nervous system was shown to increase markedly and rapidly following section of the contralateral postganglionic neurones. The enzyme activity of the operated bladder was 32% of the control 3 days postoperatively, while at the last observation, 25 days postoperatively, it was 86%. As judged from additional studies on totally denervated bladders and on totally decentralized bladders the increase found in the enzyme activity was not due to ingrowth of nerves from outside or to unspecific acetylcholine synthesis neither was it due to increase in bladder wall tension or to increase in tissue mass.

The autonomic innervation of the human urinary bladder, bladder neck and urethra: a histochemical study

The autonomic innervation of smooth muscle in fresh biopsy specimens of the human urinary bladder, bladder neck and urethra has been examined using specific neurohistochemical techniques. Acetylcholinesterase-containing nerve fibers have been demonstrated amongst the smooth muscle cells in all the biopsy samples. Enzyme-positive fibers formed a plexus, the density of which varied dependent upon the region from which the biopsy material was obtained. Catecholamine (noradrenaline)-containing autonomic nerve fibers were observed amongst smooth muscle cells of the vesico-urethra junction; other than for perivascular nerve plexuses. Noradrenergic fibers were absent from biopsy samples of other regions. Juxtamural, acetylcholinesterase-positive neurones were present in some samples, and a proportion of these cell bodies were closely related to noradrenergic nerve terminal regions. These findings are discussed in relation to those of other workers who have examined the innervation of the mammalian lower urinary tract.

Compensatory increase of responses to nerve stimulation of the partially denervated rat urinary bladder

The rat urinary bladder was deprived of half of its innervation by removing the pelvic ganglion on one side. The motor response of such a partially denervated bladder to stimulation of the pelvic nerve on the other side were examined 1 week, 1 month and 2 months postoperatively. On all three occasions the increase in pressure of the operated bladder was larger than that of the control bladder; the enlargement was most marked 2 months after operation. The responses were further enlarged by eserine, and markedly reduced by atropine. The present results combined with those of previous investigations, showing a rapid recovery in the activity of the acetylcholine forming enzyme from a reduced level and a transient supersensitivity to chemical stimuli after unilateral removal of the pelvic ganglion, suggest that the enlarged responses to nerve stimulation 1 week postoperatively are mainly due to sensitization, while those observed at the later stages are due to collateral sprouting from the cholinergic nerve fibres of the intact pelvic nerve.

Adrenergic reinnervation of the denervated rat urinary bladder

In rats undergoing unilateral extirpation of the pelvic ganglion, the adrenergic innervation disappeared on the ipsilateral side of the urinary bladder. It had reappeared after 6--9 weeks.

The role of the hypogastric nerve in bladder and urethral activity of the dog

1. Stimulation of the hypogastric nerves increased the pressure in both the bladder and urethra of anaesthetized female dogs. 2. The responses were reduced but not abolished by the alpha-adrenoceptor antagonist phentolamine, whereas the beta-adrenoceptor antagonist propranolol was either without effect or increased the responses. Atropine, methysergide and hexamethonium were without effect. 3. Close arterial injection of phenylephrine increased and isoprenaline decreased urethral pressure but both produced only a slight increase in bladder pressure. 4. Hypogastric nerve stimulation reduced subsequent responses of the bladder and urethra to pelvic nerve stimulation or to close arterial injection of acetylcholine. Isoprenaline, but not phenylephrine, also had an inhibitory action and 5-hydroxytryptamine enhanced the responses. 5. In the presence of hexamethonium the inhibitory action of isoprenaline still occurred but 5-hydroxytryptamine no longer enhanced the responses, suggesting that 5-hydroxytryptamine acts on the ganglia and isoprenaline acts, at least partially, on smooth muscle. 6. These results suggest that the role of the hypogastric nerves may be to modify inputs to the bladder and urethra as well as to act directly on the smooth muscle.

Sympathetic innervation of the urinary bladder and urethral muscle in the pig

The sympathetic innervation of the lower urinary tract was studied in the female and male pig using a specific histochemical technique for visualization of noradrenaline containing nerves. In smooth muscle from the detrusor few evenly distributed adrenergic nerve terminals were found. A greater number of terminals were observed in the trigone, bladder neck and urethra. There was no sex difference. In smooth muscle specimens from pig detrusor and trigone sympathetic nerve terminals were more abundant than in corresponding tissue from humans.

Acetylcholine synthesis and its dependence on nervous activity

The findings discussed in this paper mainly derived from studies on salivary glands, serving as model organs, indicate that the capacity to form the neurotransmitter acetylcholine, as judged by the activity of choline acetyltransferase, is influenced by the traffic of nerve impulses, as a long term effect. In the glands, choline acetyltransferase seems to be exclusively localized to the cholinergic nerves. In the postganglionic parasympathetic nerves of the glands, the activity of choline acetyltransferase decreases when the flow of secretory impulses in these nerves is abolished or reduced either by isolating the nerves from the central nervous system, surgically or pharmacologically, or by diminishing the reflex activation of the glands from the mouth. The opposite occurs when the reflex activation of the salivary glands is enhanced, i.e. the activity of choline acetyltransferase increases. Observations on various other organs are quoted in support of the view that the traffic of nerve impulses is of importance for the activity of the enzyme. An increase in choline acetyltransferase activity also occurs in some salivary glands after sympathetic denervation. This puzzling observation is discussed in relation to impulse traffic. Increased nerve impulse traffic and collateral sprouting seem to be responsible for the rapid restitution of choline acetyltransferase activity from a low level in an organ partially deprived of its cholinergic nerve supply.

Transient supersensitivity in the partially denervated urinary bladder of the rat

When examined 6-7 days after the unilateral removal of the pelvic ganglion, the detrusor muscle of the rat was found to be sensitized to methacholine and noradrenaline. The threshold doses were lower while the intravesical pressure responses to doses above threshold were increased. In contrast, bladders examined 25-30 days after the partial denervation lacked signs of sensitization. It is suggested that the contralateral nervous pathway is responsible for the rapid disappearance of the supersensitivity.

The effect of pelvic nerve stimulation and some drugs on the urethra and bladder of the dog

Pelvic nerve stimulation caused an increase in pressure in both the urethra and bladder of anaesthetised dogs. The increases were only partially blocked by intravenous injection of atropine and were not significantly reduced by phentolamine, propranolol or methysergide. Quinidine produced some reduction in the bladder but not the urethral response. Hexamethonium reduced but did not abolish the responses to pelvic nerve stimulation. Close arterial injection of acetylcholine and 5-hydroxytryptamine increased the bladder and urethral pressures; noradrenaline produced a biphasic increase in urethral pressure but had no effect on the bladder; ATP increased bladder pressure but the response of the urethra was variable. The results indicate that some fibres in the pelvic nerve to the urethra as well as to the bladder are atropine resistant and suggest that transmission does not involve 5-hydroxytryptamine or noradrenaline and probably not ATP. The significance for treatment of detrusor dysfunction is discussed.

Experimental studies on the acetylcholinesterase-positive nerves in the ovary of the rat

Adrenergic and acetylcholinesterase (AChE)-positive nerves were studied in the rat ovary four days after various experimental denervation procedures. Ablation of pelvic parasympathetic nerves (pelvic neurectomy [PN]) or abdominal vagotomy (AV) had no obvious affect on the adrenergic of AChE-positive nerves in the ovary. Section of the mesovarium resulted in the loss of all histochemically demonstrable adrenergic and AChE-positive nerves. Chemical sympathectomy with 6-hydroxydopamine (6-HD) resulted in the loss of all histochemically demonstrable adrenergic nerves. A few AChE-positive nerves remained in the hilar and medullary regions following chemical sympathectomy. When the presumptive parasympathectomy procedures (AV and PN) were combined with chemical sympathectomy, again no adrenergic nerves remained, however a few hilar and medullary AChE-positive fibers persisted after sympathectomy plus PN, but no AChD-positive fibers were demonstrable in the AV plus 6-HD group. These findings show that most of the AChE- in ovarian nerves is localized in adrenergic nerves. It is suggested that the few AChE-positive fibers remaining in the ovarian hilar area after 6-HD treatment of 6-HD plus PN are derived from the vagus. These few AChE-positive nerves may be postganglionic vagal parasympathetic or they may be sensory fibers.

Choline acetyltransferase activity in the denervated urinary bladder of the rat

After extirpation of the pelvic ganglia the choline acetyltransferase activity decreased markedly indicating that most of the postganglionic cholinergic neurones of the bladder take this route. A small decrease in the activity of this enzyme was found after section of the hypogastric nerve, showing that these nerves contribute to some extent to the cholinergic innervation. The residual enzyme activity found after a combination of the two surgical procedures suggests that neurones relay distal to the level of the section of the hypogastric nerves and pass outside the pelvic ganglia and (or) that neurones pass the pelvic ganglia and relay distal to them. Electrical stimualtion of the hypogastric nerves after extirpation of the pelvic ganglia and the use of blocking drugs showed on the existence of cholinergic neurones passing outside the pelvic ganglia, some of them relaying distal to the point of stimulation.

Adrenergic and Cholinergic Nerves of the Human Urethra and Urinary Bladder. A histochemical study

The occurrence and distribution of adrenergic and acetylcholine esterase (AChE) positive nerves in the human urethra and urinary bladder were studied histochemically with the fluorescence method of Falck and Hillarp, and the copper thiocholine method of Koelle and Friedenwald. Both types of nerves were mainly confined to the layers of smooth muscle cells in the walls of the organs. In all parts of the urethra, there was a scanty supply of adrenergic nerves. Few adrenergic nerves were also found in the urinary bladder, except in the trigone area, where they were abundant. AChE-positive nerves were uniformly and richly distributed in the urinary bladder. Throughout the urethra the distribution of AChE-positive nerve fibres was uniform, but the number was clearly less than in the urinary bladder. No intrmurally located adrenergic or AChE-Positive ganglion cells could be demonstrated.

Responses of the denervated rat urinary bladder to alfa adrenoceptor stimulation

The contractile responses of the rat detrusor muscle to noradrenaline were increased 2-3 weeks after partial denervation but had returned to control values 6-9 weeks after the denervation, probably because of reinnervation of denervated muscle cells. 6-9 weeks after partial denervation the excitatory alpha-adrenoceptor mediated response to stimulation of the remaining intact nerves was predominant, masking the subsequent inhibitory beta-receptor response, which at this time was seen only after alpha-receptor blockade. The possibility of an outgrowth of adrenergic fibres activating alpha-receptors in muscle cells normally not innervated by adrenergic nerves is discussed.

Stimulation of adrenergic nerve fibres to the urinary bladder of the rat

The contraction of the rat detrusor muscle caused by electrical stimulation of the hypogastric or pelvic nerves was followed by relaxation when the nerves were stimulated for a short period. The relaxation was more pronounced when the initial contraction was reduced by atropine. It was found to be mediated by adrenergic fibres acting on inhibitory beta2-receptors. Stimulation of the hypogastric or pelvic nerves at high frequencies increased the contractile response probably via adrenergic fibres activating excitatory alpha-receptors.