Analysis of responses to sympathetic nerve stimulation in the feline pulmonary vascular bed.

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Title:	Analysis of responses to sympathetic nerve stimulation in the feline pulmonary vascular bed.
Author:	Hyman, A L : Kadowitz, P J
Citation:	J-Appl-Physiol. 1989 Jul; 67(1): 371-6
Abstract:	The adrenergic receptor subtypes mediating the response to sympathetic nerve stimulation in the pulmonary vascular bed of the cat were investigated under conditions of controlled blood flow and constant left atrial pressure. The increase in lobar vascular resistance in response to sympathetic nerve stimulation was reduced by prazosin and to a lesser extent by yohimbine, the respective alpha 1- and alpha 2-adrenoceptor antagonists. Moreover, in animals pretreated with a beta-adrenoceptor antagonist to prevent an interaction between alpha- and beta 2-adrenoceptors, responses to nerve stimulation were reduced by prazosin, but yohimbine had no significant effect. On the other hand, in animals pretreated with a beta-adrenoceptor antagonist, yohimbine had an inhibitory effect on responses to tyramine and to norepinephrine. Propranolol had no significant effect on the response to nerve stimulation, whereas ICI 118551, a selective beta 2-adrenoceptor antagonist, enhanced responses to nerve stimulation and injected norepinephrine. The present data suggest that neuronally released norepinephrine increases pulmonary vascular resistance in the cat by acting mainly on alpha 1-adrenoceptors and to a lesser extent on postjunctional alpha 2-adrenoceptors but that this effect is counteracted by an action on presynaptic alpha 2-receptors. The present studies also suggest that neuronally released norepinephrine acts on beta 2-adrenoceptors and that the response to sympathetic nerve stimulation represents the net effect of the adrenergic transmitter on alpha 1-, alpha 2-, and beta 2-adrenoceptors in the pulmonary vascular bed.
Review References:	None
Notes:	Copyright American Physiological Society. Abstracts are reprinted by the permission of the publisher of the journal for volume, pages, and dates cited. Hypertext links to electronic journal sites, if available, can be found in the the Peer Reviewed Journal List on the IBIDS home page.
Language:	English
Publication Type:	Journal-Article
Keywords:	Lung blood supply : Lung innervation : Prazosin pharmacology : Pulmonary Circulation drug effects : Sympathetic Nervous System physiology : Vascular Resistance drug effects : Yohimbine pharmacology
URL:	http://www.jap.org