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Action of adenosine receptor antagonists on the cardiovascular response to defence area stimulation in the rat
Author(s) -
Lambert J.H.,
DawidMilner M.S.,
SilvaCarvalho L.,
Spyer K.M.
Publication year - 1994
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.1476-5381.1994.tb16188.x
Subject(s) - adenosine , stimulation , blood pressure , heart rate , medicine , adenosine receptor , endocrinology , adenosine a1 receptor , chemistry , receptor , pharmacology , anesthesia , agonist
1 The action of adenosine in the mediation of the cardiovascular changes associated with the defence reaction has been investigated in the rat using two A 1 receptor antagonists. 2 Cumulative doses of 1,3 dipropyl‐cyclopentylxanthine (DPCPX) (0.3–3 mg kg −1 ) and ethanol (0.03–0.25 ml) and bolus doses of DPCPX (3 mg kg −1 ) and 8‐sulphophenyltheophylline (8‐SPT) (20 mg kg −1 ) were given into α‐chloralose, paralysed and artificially ventilated rats. Recordings were made of arterial blood pressure and heart rate. 3 Ethanol, the vehicle for DPCPX, failed to modify the magnitude of the defence response; however, cumulative doses of DPCPX produced a dose‐dependent decrease in the HDA (hypothalamic defence area)‐evoked increase in arterial blood pressure, accompanied by a similar fall in the magnitude of the evoked heart rate response. 4 The evoked rise in arterial blood pressure was reduced significantly by intravenous injection of DPCPX (3 mg kg −1 ) but not 8‐SPT (20 mg kg −1 ), a purely peripherally acting adenosine antagonist. 5 These results suggest that adenosine acting at A 1 receptors located in the central nervous system, is involved in the HDA‐evoked pressor response. Whilst the site of action of the A 1 receptors is not known, possible locations are discussed.