pISSN 1226-4512 eISSN 2093-3827

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Original Article

Korean J Physiol Pharmacol 2021; 25(6): 525-532

Published online November 1, 2021 https://doi.org/10.4196/kjpp.2021.25.6.525

Copyright © Korean J Physiol Pharmacol.

Roles for α1-adrenoceptors during contractions by electrical field stimulation in mouse vas deferens

Hadeel A. Alsufyani1 and James R. Docherty2,*

1Department of Physiology, King Abdulaziz University, Jeddah 21589, Saudi Arabia, 2Department of Physiology, Royal College of Surgeons in Ireland (RCSI), Dublin D02 YN77, Ireland

Correspondence to:James R. Docherty
E-mail: docherty@rcsi.ie

Received: April 19, 2021; Revised: June 1, 2021; Accepted: June 1, 2021

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright © Korean J Physiol Pharmacol, pISSN 1226-4512, eISSN 2093-3827

Abstract

We have investigated the relative roles of α1-adrenoceptors and purinoceptors in contractions to low and high frequency stimulation of the mouse vas deferens, in terms of the time course of responses. In separate experiments, isometric contractile responses were obtained to 10 pulses at 1 Hz and 40 pulses at 10 Hz. Responses to 1 Hz stimulation consisted of a series of discrete peaks. The α1A-adrenoceptor antagonist RS100329 (10–9M–10–7M) significantly reduced the response to the first pulse, the α1D-adrenoceptor antagonist BMY7378 (10–7M–10–6M) significantly reduced the response to the first two pulses, and the non-selective α1-adrenoceptor antagonist prazosin (10–8M) reduced the response to the first 4 pulses at 1 Hz. Responses to 10 Hz stimulation consisted of an early peak response and a maintained plateau response. RS100329 significantly reduced the peak response but did not significantly affect the plateau response. Prazosin, significantly reduced both the peak and plateau responses. The α1A-adrenoceptor antagonist RS17053 in high concentrations reduced mainly the plateau response leaving a clear early peak response. The plateau response of contraction was almost abolished by the purinoceptor antagonist suramin. These results suggest that there is a relatively minor early α1D-adrenoceptor and a larger early α1A-adrenoceptor component to stimulationevoked contractions of mouse vas deferens, but the major α1-adrenoceptor component is revealed by prazosin to be α1B-adrenoceptor mediated. α1B-Adrenoceptor activation probably facilitates contractions mediated by other α1-adrenoceptors and by purinoceptors. These results suggest that combined non-selective α1-adrenoceptor blockade, particularly α1B-adrenoceptor blockade, in addition to P2X1-purinoceptor blockade is useful in reducing male fertility.

Keywords: Adrenergic, Fertility, Muscle, smooth, Neuromuscular junction, Vas deferens