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Evidence that central 5‐HT 1A ‐receptors play a role in the von Bezold‐Jarisch reflex in the rat
Author(s) -
Bogle Richard G.,
Pires Jose G.P.,
Ramage Andrew G.
Publication year - 1990
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.1476-5381.1990.tb14088.x
Subject(s) - pindolol , buspirone , reflex , spiperone , reflex bradycardia , bradycardia , endocrinology , medicine , sulpiride , 5 ht receptor , agonist , chemistry , atenolol , pharmacology , receptor , antagonist , serotonin , heart rate , blood pressure
1 The effects of intracisternal (i.c.) application of putative 5‐hydroxytryptamine (5‐HT) 1A antagonists on the reflex bradycardia evoked by injection of phenylbiguanide (i.v.) were investigated in anaesthetized, atenolol‐pretreated rats. 2 Intracisternal application of spiperone (100 μg kg −1 ) reversibly attenuated the reflex bradycardia whilst the same dose given i.v. had no effect. The bradycardia was also attenuated by i.e. methiothepin (200 μg kg −1 ), (±)‐pindolol (100 μg kg −1 ) and buspirone (200 μ kg −1 ) but was not attenuated by antagonists selective for α 1 ‐adrenoceptors (alfuzosin; 100 μg kg −1 ), 5‐HT 2 ‐receptors (BW 501C67; 100 μg kg −1 ) or dopamine D 2 ‐receptors ((−)−sulpiride; 100 μg kg −1 ) given i.e. 3 It is concluded that the 5‐HT 1A ‐receptor antagonist action of intracisternally applied spiperone, methiothepin, (±)‐pindolol and buspirone is responsible for the ability of these drugs to attenuate reversibly the excitation of cardiac vagal motoneurones caused by activation of the von Bezold‐Jarisch reflex.