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Sensory neurone‐specific receptor‐mediated regulation of micturition reflex in urethane‐anaesthetized rats
Author(s) -
Honda Masashi,
Takenaka Atsushi,
Inoue Seiya,
Chancellor Michael B.,
Yoshimura Naoki
Publication year - 2012
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/j.1464-410x.2011.10400.x
Subject(s) - urination , medicine , nociception , reflex , agonist , capsaicin , receptor , sensory system , nociceptor , noxious stimulus , trpv1 , anesthesia , pharmacology , endocrinology , neuroscience , transient receptor potential channel , urinary system , psychology
What's known on the subject? and What does the study add? A novel family of G‐protein‐coupled receptors has been identified in rat dorsal root ganglia and named as sensory neuron‐specific receptors (SNSRs) and these receptors are expressed exclusively in a subset of small‐diameter primary afferent neurons involved in transmission of nociceptive information. However, it is not known whether SNSRs have a role in the control of the micturition reflex. This study demonstrated that in urethane‐anaesthetised rats activation of SNSRs can inhibit the micturition reflex via the pathways independent of capsaicin sensitive C‐fibres. OBJECTIVE• To investigate the effect of sensory neurone‐specific receptors (SNSRs) activation on the micturition reflex in rats.MATERIALS AND METHODS• Continuous cystometrograms (CMGs, 0.04 mL/min) were performed in female Sprague‐Dawley rats under urethane anaesthesia. • After stable micturition cycles were established, a selective rat SNSR1 agonist, bovine adrenal medulla 8–22 (BAM8–22), was administered intravenously (i.v.) or intrathecally (i.t.) in normal rats or rats pretreated with capsaicin 4 days before the experiments. • Micturition variables were recorded and compared before and after drug administration.RESULTS• Administration (i.v.) of BAM8–22 (3–100 µg/kg) significantly increased intercontraction intervals in a dose‐dependent fashion, but did not affect residual urine or baseline pressure at any doses tested. • Administration (i.t.) of BAM8–22 (0.01–0.3 µg) also increased intercontraction intervals in a dose‐dependent fashion, but did not affect residual urine or baseline pressure at any doses tested. • These inhibitory effects of i.v. (30 µg/kg) or i.t. (0.3 µg) administration of BAM8–22 still occurred after capsaicin pretreatment.CONCLUSIONS• These results indicate that in urethane‐anaesthetized rats activation of SNSRs can inhibit the micturition reflex via pathways independent of capsaicin‐sensitive C‐fibres. • Thus SNSRs could be a potential target for the treatment of bladder dysfunction, e.g. overactive bladder.