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An analysis of the purinergic component of active muscle vasodilatation obtained by electrical stimulation of the hypothalamus in rabbits
Author(s) -
Shimada Steven G.,
Stitt John T.
Publication year - 1984
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1984.tb16522.x
Subject(s) - vasodilation , purinergic receptor , adenosine , stimulation , medicine , endocrinology , skeletal muscle , aminophylline , chemistry
1 In anaesthetized rabbits, electrical stimulation of the hypothalamus in areas analogous to the defence area in cats produces the ‘defence reaction.’ This response includes signs of arousal and a large increase in blood flow to skeletal muscle in the hind limb caused by a vasodilatation in the skeletal muscle vasculature. 2 The vasodilatation is a sympathetic response, and it is not dependent upon muscle activity in the hind limb. 3 The muscle vasodilatation is insensitive to α‐adrenoceptor, β‐adrenoceptor, cholinoceptor and histamine receptor antagonists. 4 Intra‐arterial injections of the purinoceptor agonists, adenosine triphosphate (ATP) and adenosine, mimic the vasodilatation produced by electrical stimulation. 5 The P 1 ‐purinoceptor blocker, aminophylline, attenuates adenosine‐induced vasodilatation, but it does not affect the vasodilatation produced by ATP or hypothalamic stimulation. 6 The P 2 ‐purinoceptor blocker, antazoline, attenuates the vasodilatation produced by both ATP and hypothalamic stimulation. 7 Our results suggest that the muscle vasodilatation produced by hypothalamic stimulation is mediated by purinergic nerves which release ATP and act on P 2 ‐purinoceptors.