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No effect of pertussis toxin on peripheral prejunctional α 2 ‐adrenoceptor‐mediated responses and on endothelium‐dependent relaxations in the rat
Author(s) -
Docherty J.R.
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.tb15807.x
Subject(s) - pertussis toxin , medicine , endocrinology , acetylcholine , bordetella pertussis , stimulation , chemistry , contraction (grammar) , histamine , agonist , biology , g protein , receptor , genetics , bacteria
1 We have investigated the effects of pertussis toxin treatment on a variety of peripheral tissues in the rat. 2 Incubation with pertussis toxin (1 μg ml −1 ) in vitro failed to alter the negative inotropic actions of acetylcholine in rat left atria. 3 Pretreatment with pertussis toxin (6 μg kg −1 , i.v., 3–4 days) abolished the negative inotropic actions of acetylcholine in rat left atria. 4 Pretreatment with pertussis toxin (40 μg kg −l , i.v., 3–4 days) failed to alter the prejunctional inhibitory actions of the α 2 ‐adrenoceptor agonist xylazine, either in terms of the isometric contraction to a single stimulus in rat vas deferens or in terms of stimulation‐evoked overflow of tritium in atria pre‐incubated with [ 3 H]‐noradrenaline. 5 Pretreatment with pertussis toxin (6 μg kg −1 , i.v., 3–4 days) failed to affect, and pertussis toxin (40 μg kg −1 , i.v., 3–4 days) potentiated endothelium‐dependent relaxations of rat aorta to histamine and acetylcholine. 6 It seems unlikely that peripheral prejunctional actions of α 2 ‐adrenoceptor agonists or endothelium‐dependent relaxations of rat aorta involve pertussis toxin‐sensitive G proteins.