Int Neurourol J.  2018 Jun;22(2):83-89. 10.5213/inj.1836078.039.

Capsaicin-Sensitive Sensory Nerves Indirectly Modulate Motor Function of the Urinary Bladder

• Chang HH
• Chang SJ
• Hsieh CH
• Hsu CK
• Yang SS

• KMID: 2417780
• DOI: http://doi.org/10.5213/inj.1836078.039

Abstract

PURPOSE
The urinary bladder (UB) is innervated by both sensory and autonomic nerves. Recent studies have shown that sensory neuropeptides induced contractions in the detrusor muscle. Therefore, in a mouse model, we investigated the presence of interactions between the submucosal sensory nerves and the autonomic nerves that regulate the motor function of the detrusor muscle.
METHODS
UB samples from male C57BL/6 mice were isolated, cut into strips, and mounted in an organ bath. Dose-response curves to norepinephrine and phenylephrine were studied in UB strips with and without mucosa, and the effects of preincubation with a receptor antagonist and various drugs on relaxation were also studied using tissue bath myography.
RESULTS
Phenylephrine-induced relaxation of the UB strips showed concentration-related effects. This relaxation appeared in both mucosa-intact and mucosa-denuded UB strips, and was significantly inhibited by lidocaine, silodosin, and guanethidine (an adrenergic neuronal blocker). Meanwhile, phenylephrine-induced relaxation was inhibited by pretreatment with propranolol and calcitonin gene-related peptide (CGRP)-depletory capsaicin in UB strips with and without mucosa.
CONCLUSIONS
The present study suggests that phenylephrine activates the α-1A adrenergic receptor (AR) of the sensory nerve, and then activates capsaicin-sensitive sensory nerves to release an unknown substance that facilitates the release of norepinephrine from adrenergic nerves. Subsequently, norepinephrine stimulates β-ARs in the detrusor muscle in mice, leading to neurogenic relaxation of the UB. Further animal and human studies are required to prove this concept and to validate its clinical usefulness.

Keyword

Submucosal sensory nerve; Alpha-1 adrenergic receptors; Silodosin; Phenylephrine; Capsaicin

MeSH Terms

Adrenergic Neurons
Animals
Autonomic Pathways
Baths
Calcitonin Gene-Related Peptide
Capsaicin
Guanethidine
Humans
Lidocaine
Male
Mice
Mucous Membrane
Myography
Neuropeptides
Norepinephrine
Phenylephrine
Propranolol
Receptors, Adrenergic
Receptors, Adrenergic, alpha-1
Relaxation
Urinary Bladder*
Calcitonin Gene-Related Peptide
Capsaicin
Guanethidine
Lidocaine
Neuropeptides
Norepinephrine
Phenylephrine
Propranolol
Receptors, Adrenergic
Receptors, Adrenergic, alpha-1