MP09-02 DIFFERENTIAL DISTRIBUTION OF HYPERPOLARIZATION-ACTIVATED CHANNELS IN PEPTIDERGIC AND CHOLINERGIC FIBERS OF THE HUMAN BLADDER

Abstract

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology I1 Apr 2018MP09-02 DIFFERENTIAL DISTRIBUTION OF HYPERPOLARIZATION-ACTIVATED CHANNELS IN PEPTIDERGIC AND CHOLINERGIC FIBERS OF THE HUMAN BLADDER Pradeep Tyagi, Mahendra Kashyap, and Naoki Yoshimura Pradeep TyagiPradeep Tyagi More articles by this author , Mahendra KashyapMahendra Kashyap More articles by this author , and Naoki YoshimuraNaoki Yoshimura More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.328AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Hyperpolarization-activated cyclic nucleotide-gated channels (HCN) have been previously identified by us in the cell bodies of rat bladder afferent neurons, where they carry currents to perform diverse functions, including the hyperpolarization activated Ih current. Recent studies indicate expression of HCN channels in human bladder and suggest their involvement in the modulation of bladder contractility. HCN channels in neurons are responsible for setting the resting membrane potential, regulate discharge patterns and network activity. Present study was conducted to identify and characterize HCN1 and HCN4 immunoreactive (IR) nerve fibers in urothelium, suburothelium and detrusor regions of human bladder by immunocytochemistry. METHODS Human bladders were obtained from 3 deceased organ donors (either male or female between 16 to 82 years old) with full ethical approval. Bladders were surgically separated into urothelium (containing suburothelium) and detrusor section. Tissue regions from trigone region were cryopreserved and sectioned into 10μm thick cryosections. Sections were fixed in chilled acetone and processed for immunohistochemistry using antibodies for either HCN1 and HCN4 primary antibody. Double immunostaining with neuronal markers of calcitonin gene related peptide (CGRP) and choline acetyltransferase (ChAT) was performed. RESULTS The expression of HCN1 was relatively stronger in urothelium, sub urothelium and detrusor, whereas HCN4 expression was strongest in detrusor and suburothelium, while expression in urothelium was minimal. The co-localization of HCN1 and CGRP+ve peptidergic neuron fibers was higher than the co-localization of HCN1 with ChAT +ve cholinergic fibers in suburothelium and detrusor regions. The HCN4 immunoreactivity co-localized with the red immunoreactivity of ChAT much strongly in detrusor than in sub-urothelium. CONCLUSIONS Based on these findings, HCN ion channel mechanisms are postulated to modulate the release of neurotransmitters and initiate action potentials in response to transmitter-evoked depolarization forafferent (HCN1) and efferent ( HCN4) arm of micturition reflex. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e105-e106 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Pradeep Tyagi More articles by this author Mahendra Kashyap More articles by this author Naoki Yoshimura More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...