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Prejunctional alpha 2-adrenoceptors inhibit acetylcholine release from cholinergic nerves in equine airways

Prejunctional alpha 2-adrenoceptors inhibit acetylcholine release from cholinergic nerves in... Yu, Mingfu, Zhaowen Wang, and N. Edward Robinson. Prejunctional a,-adrenoceptors inhibit acetylcholine release from in equines. Am. J. Physiol. 265 (Lung Cell. MOL.Physiol. 9): L565-L570, 1993.-To determine the presenceand function of a,-adrenoceptorson innervating horse smooth muscle,the effects of somea,-adrenoceptor agents on contractions of and acetylcholine (ACh) releasefrom equine smooth muscle preparationswerestudied. Muscle contractions wereelicited by either electrical field stimulation (EFS) or exogenous ACh. ACh releasewas induced by EFS and measuredby high-pressure liquid chromatography and electrochemical detection. The a,-adrenoceptor agonists clonidine (10s7 to 10e5 and UK-14,304 (10m8 to 10B6 dependently inhibited ACh release the contractile response EFS but not the and to response exogenous to ACh. This inhibition was attenuated by the a,-adrenoceptor antagonistsyohimbine and idazoxan but not by the a,-adrenoceptor antagonist prazosin. These results indicate that a,-adrenoceptors exist on choline@ innervating equine smoothmuscle,and activation of these receptorsinhibits neurotransmission. The observation that yohimbine alone had little effect on the contractile responseto EFS suggeststhat, under these experimental conditions, endogenousnorepinephrine had no influence on tracheal neurotransmissionvia prejunctional cy2adrenoceptors. neurotransmission; clonidine; idazoxan; yohimbine; sponse to EFS but not to ACh. Although direct ‘measurement of ACh release can provide dependable evidence about prejunctional modulation, previous studies on prejunctional a2-adrenoceptors of have been mostly http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Lung Cellular and Molecular Physiology The American Physiological Society

Prejunctional alpha 2-adrenoceptors inhibit acetylcholine release from cholinergic nerves in equine airways

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Publisher
The American Physiological Society
Copyright
Copyright © 1993 the American Physiological Society
ISSN
1040-0605
eISSN
1522-1504
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Abstract

Yu, Mingfu, Zhaowen Wang, and N. Edward Robinson. Prejunctional a,-adrenoceptors inhibit acetylcholine release from in equines. Am. J. Physiol. 265 (Lung Cell. MOL.Physiol. 9): L565-L570, 1993.-To determine the presenceand function of a,-adrenoceptorson innervating horse smooth muscle,the effects of somea,-adrenoceptor agents on contractions of and acetylcholine (ACh) releasefrom equine smooth muscle preparationswerestudied. Muscle contractions wereelicited by either electrical field stimulation (EFS) or exogenous ACh. ACh releasewas induced by EFS and measuredby high-pressure liquid chromatography and electrochemical detection. The a,-adrenoceptor agonists clonidine (10s7 to 10e5 and UK-14,304 (10m8 to 10B6 dependently inhibited ACh release the contractile response EFS but not the and to response exogenous to ACh. This inhibition was attenuated by the a,-adrenoceptor antagonistsyohimbine and idazoxan but not by the a,-adrenoceptor antagonist prazosin. These results indicate that a,-adrenoceptors exist on choline@ innervating equine smoothmuscle,and activation of these receptorsinhibits neurotransmission. The observation that yohimbine alone had little effect on the contractile responseto EFS suggeststhat, under these experimental conditions, endogenousnorepinephrine had no influence on tracheal neurotransmissionvia prejunctional cy2adrenoceptors. neurotransmission; clonidine; idazoxan; yohimbine; sponse to EFS but not to ACh. Although direct ‘measurement of ACh release can provide dependable evidence about prejunctional modulation, previous studies on prejunctional a2-adrenoceptors of have been mostly

Journal

AJP - Lung Cellular and Molecular Physiology – The American Physiological Society

Published: Dec 1, 1993

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