Journal of the Autonomic Nervous System
Expression of neuropeptides and nitric oxide synthase in neurones innervating the inflamed rat urinary bladder
Introduction
Several important changes of urinary bladder function and sensation accompany an acute urinary bladder inflammation in humans. The neuronal and mechanical events associated with bladder filling and micturition become hypersensitive and progressively painful. This affects normal bladder capacity and frequency of micturition. In animals, experimental inflammation of the urinary bladder has been induced by instillation of irritant chemicals such as mustard oil, turpentine oil or capsaicin into the bladder 1, 16, 17, 18, 19, 25, 33, 34. The inflammatory vesical response is characterized by oedema, plasma protein extravasation from the vasculature, leukocyte infiltration of the bladder tissue and a marked and prolonged hyperactivity of the detrusor muscle. Since the bladder contractions following application of mustard oil are absent in denervated bladders, a neurogenic mechanism for the induction of an unstable and hyperreflexic detrusor muscle was postulated [34]. It was suggested that detrusor hyperexcitability was mainly due to alterations in the afferent innervation of the bladder. Indeed, previously unresponsive primary afferent neurones in the pelvic nerves were shown to change their receptive properties and develop ongoing activity following the induction of a cystitis 16, 17, 18. However, the rat urinary bladder receives a dual afferent innervation that originates from sensory neurones located in lumbosacral dorsal root ganglia (L5–S1) and thoracolumbar dorsal root ganglia (T11–L3) and whose axons travel in the pelvic and hypogastric nerves, respectively. Yet, little attention has been paid so far to the latter population of afferent neurones. Furthermore, changes in the efferent innervation of the bladder could not be excluded.
Whether neuropeptides are involved in the mediation of bladder hyperactivity following inflammation has been a matter of discussion for many years [29]. Yet, little information is available about alterations in the expression of neuropeptides in the bladder reflex pathway in this type of functional disorder. Neuropeptide-containing, capsaicin-sensitive primary afferent neurones innervating the bladder may be a part of the spinal, vesicovesical excitatory reflex-loop mediating detrusor hyperreflexia 13, 19, 29. Capsaicin-sensitive afferents, expressing neuropeptides like tachykinins and calcitonin gene-related peptide (CGRP), serve not only a sensory but also a local effector function, due to a release of peptides from their peripheral endings upon stimulation. Substance P (SP) and CGRP released from these nerves following induction of a cystitis may have pro-inflammatory effects in the periphery [15]and may play a role as neurotransmitters and/or neuromodulators in bladder ganglia and in the spinal cord.
Galanin (GAL) has been reported to be present in numerous nerve fibres in the urinary bladder of man and rat [5]. GAL was shown to influence the activity of vesical smooth muscles 11, 47including the rat urinary bladder and modulate neural transmission in autonomic ganglia 46, 56and at neuromuscular junctions [30]. However, the origin and distribution of the galaninergic innervation of the bladder is still an unsettled question.
In recent years, there is accumulating evidence indicating that nitric oxide synthase (NOS), the enzyme which forms the gaseous NO in various tissues including the nervous system is of high significance in this context. Histochemical 49, 51and pharmacological studies 22, 40have suggested an involvement of NO in visceral sensory pathways in pathological states. NO may further play an important role as a non-adrenergic, non-cholinergic (NANC) neurotransmitter or modulator in the efferent innervation to the urinary bladder 39, 48. However, the functional significance of the nitrergic innervation of the detrusor muscle remained uncertain.
In the present study, we investigated the expression of SP, CGRP, GAL and NOS in neurones of the dorsal root ganglia and major pelvic ganglia innervating the rat urinary bladder. Moreover, a comparison was made between tissue from normal animals and rats with a mustard oil-induced cystitis. The question was addressed, whether the reported electrophysiological changes that occur after induction of bladder inflammation are paralleled by neuroplastic changes in the chemical coding of these neurones. Thus indirect evidence for an involvement of the examined substances in the modulation of hyperexcitability of bladder reflexes was obtained.
Section snippets
Animals and surgical procedure
Eighteen male Sprague-Dawley rats (b.wt. 340–410 g), kept under standard laboratory conditions (12 h light/12 h dark, food and water ad libitum), were used in this study. In eleven of these animals an acute cystitis was induced by application of the irritant chemical mustard oil to the urinary bladder, while seven animals served as a sham-operated control group.
Rats were anaesthetized with i.p. injections of sodium pentobarbitone (Nembutal; 60 mg/kg) and received s.c. injections of 0.1 mg/kg
General observations
The physiological consequences of an instillation of mustard oil into the rat urinary bladder have been described in detail by McMahon and Abel [34]. In the present study we evaluated (a) the histology of the bladder tissue with regard to inflammatory signs and damage and (b) intravesical pressure and voiding frequency as control measures of a changed bladder morphology and function, thus as indicators of the effectiveness of mustard oil to induce an inflammatory response.
Histological
Morphological and physiological consequences of bladder inflammation
Several previous studies have dealt with the effects of an experimental inflammation induced by exposure of the urinary bladder to irritant chemicals (including mustard oil) in cats 17, 18and rats 25, 33, 34as a model for visceral nociception and pain. It has been shown that the effects on the vesical tissue are characterized initially by massive plasma extravasation and oedema, followed with some delay by infiltration with leukocytes, bacterial infections and (especially after mustard oil
Conclusions
The results presented here show that the previously reported hyperactivity in bladder reflex pathways following inflammation 16, 17, 18, 33is associated with a significant upregulation of the synthesis of SP, CGRP, GAL and NOS in bladder afferent fibres projecting to the upper lumbar and lumbosacral spinal cord. However, the expression of these substances showed differences at the two segmental levels which are indicative of a different regulation of the parasympathetic (excitatory) and
Acknowledgements
The authors wish to acknowledge the skilful technical assistance of Mrs. M. Drozd. This project was supported by the Bundesministerium für Forschung und Technologie, Grant No. 01KO9504.
References (57)
- et al.
The contribution of capsaicin-sensitive sensory nerves to xylene-induced visceral pain in conscious, freely moving rats
Naunyn Schmiedebergs Arch. Pharmacol.
(1988) - et al.
Nitric oxide synthase-containing neurons in rat parasympathetic, sympathetic and sensory ganglia: A comparative study
Histochem. J.
(1995) - et al.
Nitric oxide synthase-immunoreactive, adrenergic, cholinergic, and peptidergic nerves of the female rat urinary tract: A comparative study
J. Auton. Nerv. Syst.
(1995) The pharmacology of the lower urinary tract smooth muscles and penile erectile tissues
Pharmacol. Rev.
(1993)- et al.
Distribution of galanin immunoreactivity in the genitourinary tract of man and rat
Peptides
(1986) - et al.
Facilitatory role of calcitonin gene-related peptide (CGRP) on excitation induced by substance P (SP) and noxious stimuli in rat spinal dorsal horn neurons. An iontophoretic study in vivo
Brain Res.
(1991) - et al.
Excitation of rat sympathetic preganglionic neurones by selective activation of the NK 1 receptor
J. Auton. Nerv. Sys.
(1996) - et al.
Effects of nitric oxide on detrusor relaxation
J. Urol.
(1996) - et al.
Sympathetic inhibition of the urinary bladder and of pelvic ganglionic transmission in the cat
J. Physiol.
(1972) - et al.
Afferent volley patterns and the spinal release of immunoreactive substance P in the dorsal horn of the anaesthetized spinal cat
Neuroscience
(1995)
Galanin: Neuromodulatory and direct contractile effects on smooth muscle preparations
Br. J. Pharmacol.
Galanin inhibits acetylcholine release in the ventral hippocampus of the rat: Histochemical, autoradiographic, in vivo and in vitro studies
Proc. Natl. Acad. Sci. USA
Intravesical capsaicin for neurogenic bladder dysfunction
Lancet
Calcitonin gene-related peptide immunoreactivity in the spinal cord of man and eight other species
J. Neurosci.
Sensory neuropeptide interactions in the production of plasma extravasation in the rat
Neuroscience
A novel type of unmyelinated chemosensitive nociceptor in the acutely inflamed urinary bladder
Agents Actions
Activation of unmyelinated afferent fibres by mechanical stimuli and inflammation of the urinary bladder in the cat
J. Physiol.
Receptive properties of myelinated primary afferents innervating the inflamed urinary bladder of the cat
J. Neurophysiol.
Capsaicin-induced bladder hyperactivity in normal conscious rats
J. Urol.
Tachykinin effects on bladder activity in conscious normal rats
J. Urol.
Primary sensory neurones of the rat showing calcitonin gene-related peptide immunoreactivity and their relation to substance P-, somatostatin-, galanin-, vasoactive intestinal polypeptide- and cholecystokinin-immunoreactive ganglion cells
Cell Tiss. Res.
Role of spinal nitric oxide in the facilitation of the micturition reflex by bladder irritation
J. Urol.
Distribution of neurons in the major pelvic ganglion of the rat which supply the bladder, colon or penis
Cell Tissue Res
Segmental distribution and peptide content of primary afferent neurones innervating the urogenital organs and colon of male rat
J. Comp. Neurol.
Plasma extravasation in the rat urinary bladder following mechanical, electrical and chemical stimuli: Evidence for a new population of chemosensitive primary sensory afferents
Neurosci. Lett.
Evidence for localized release of substance P within rat spinal cord evoked by physiological and electrical stimuli
Neuropeptides
Evidence for a role of tachykinins as sensory tramsmitters in the activation of micturition reflex
Neuroscience
Calcitonin gene-related peptide is a potent inhibitor of substance P degradation
Eur. J. Pharmacol.
Cited by (67)
Dorsal root ganglion neurons innervating pelvic organs in the mouse express tyrosine hydroxylase
2012, NeuroscienceCitation Excerpt :In recent studies, afferent fibers in these two nerves have been characterized in mouse colorectum (Brierley et al., 2004, 2005) and urinary bladder (Xu and Gebhart, 2008) with respect to mechanosensitivity, and differentiated into mucosal, muscular/mucosal, muscular, mesenteric and serosal classes. As shown both in rat (De Groat, 1987; Keast and De Groat, 1992; Callsen-Cencic and Mense, 1997; Wang et al., 1998; Keast and Stephensen, 2000; Christianson et al., 2006; Olsson et al., 2006) and mouse (Robinson et al., 2004; Christianson et al., 2006; Spencer et al., 2008; Brumovsky et al., 2011), colorectal and urinary bladder sensory neurons synthesize a variety of neurotransmitters and associated molecules. These include excitatory neurotransmitters such as glutamate and aspartate (Keast and Stephensen, 2000), the related vesicular glutamate transporters (VGLUTs) (Olsson et al., 2006; Brumovsky et al., 2011), neuropeptides such as the calcitonin gene-related peptide (CGRP) (De Groat, 1987; Keast and De Groat, 1992; Callsen-Cencic and Mense, 1997; Wang et al., 1998; Robinson et al., 2004; Hwang et al., 2005), pituitary adenylate cyclase-activating peptide (Wang et al., 1998), substance P and somatostatin (Wang et al., 1998) or galanin (Callsen-Cencic and Mense, 1997; Wang et al., 1998).
Autonomic control of the urogenital tract
2011, Autonomic Neuroscience: Basic and ClinicalCitation Excerpt :Intramural ganglia in human bladder also contain somatostatin, bombesin, enkephalin, SP and CGRP (Dixon et al., 1997) underscoring the fact that the neurochemical profile of bladder projecting neurons varies between species. Some bladder projecting neurons also contain immunoreactivity to nNOS (Callsen-Cencic and Mense, 1997; Dixon and McKinnon, 1996; Dixon et al., 1997). The excitatory innervation of bladder smooth muscle has been a subject of study for over a century (Langley and Anderson, 1894).
The galanin peptide family in inflammation
2011, NeuropeptidesCitation Excerpt :In the remission stage of this inflammatory model (79 days post injection) galanin mRNA levels were still significantly elevated (Calza et al., 2000). Plasticity in the expression of galanin was also observed in response to acute and chronic cystitis in rats, with differences in the segmental pattern and degree of regulation (Callsen-Cencic and Mense, 1997; Girard et al., 2008). In carrageenan-induced inflammation, both the numbers of galanin mRNA-expressing neurons and galanin-LI were decreased in rat DRG 3 days post injection (Ji et al., 1995), whereas in mouse DRG the number of galanin-positive neurons was found to be time-dependent, peaking 14 days after injection of herpes simplex virus type 2.
Tachykinins and Neurogenic Inflammation at Visceral Level
2009, NeuroImmune BiologyCitation Excerpt :The human urinary bladder bears tachykinin-containing nerve fibers which follow a similar distribution to that found in rodents, although their density and levels of extractable tachykinin-LI in human tissues is lower than that present in small rodents [14,136,137]. Interestingly, the number of fibers containing tachykinins, as well as tissue content of tachykinins, were increased by chronic inflammation of the urinary bladder or bladder dysfunction (outflow obstruction) in rats [138–140]. Tachykinin-containing nerve fibers were also increased in the bladder of patients affected by idiopathic micturition disorders such as interstitial cystitis [141,142].
Bacterial Cystitis in Urogynaecology: An Update
2023, Textbook of Female Urology and Urogynecology: Clinical PerspectivesThe influence of an adrenergic antagonist guanethidine on the distribution pattern and chemical coding of caudal mesenteric ganglion perikarya and their axons supplying the porcine bladder
2021, International Journal of Molecular Sciences