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Adenosine enhancement of adrenergic neuroeffector transmission in guinea‐pig pulmonary artery
Author(s) -
Wiklund N. Peter,
Cederqvist Bo,
Gustafsson Lars E.
Publication year - 1989
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.1476-5381.1989.tb11834.x
Subject(s) - adenosine , medicine , endocrinology , purinergic receptor , adenosine receptor , stimulation , neuroeffector , adenosine receptor antagonist , inhibitory postsynaptic potential , adenosine a1 receptor , chemistry , adrenergic , biology , neurotransmission , muscle contraction , receptor , agonist
1 Adenosine and its derivatives N 6 ‐[(R)−1‐methyl‐2‐phenylethyl]adenosine (R‐PIA) or 5′‐N‐ethylcarboxamideadenosine (NECA) enhanced nerve‐induced contractile responses and augmented the basal smooth muscle tone in transmurally stimulated isolated strips of the guinea‐pig pulmonary artery. 2 Adenosine, R‐PIA and NECA enhanced contractile responses induced by noradrenaline, whereas N 6 ‐[(S)−1‐methyl‐2‐phenylethyl]‐adenosine (S‐PIA) was virtually inactive. 3 Adenosine, R‐PIA and NECA inhibited the nerve stimulation evoked release of [ 3 H]‐noradrenaline. However, the total release of [ 3 H]‐noradrenaline during the periods of NECA application was increased. 4 The nucleoside effects were blocked by the adenosine receptor antagonist 8‐ p ‐sulphophenyltheophylline. 5 8‐ p ‐Sulphophenyltheophylline inhibited nerve‐induced contractions and lowered basal muscle tone in preparations not having received any exogenous purines. 6 It is suggested that the observed stimulatory effects on muscle tone and on contractile responses to transmural nerve stimulation are mainly due to action at postjunctional stimulatory A 1 adenosine receptors. In addition, actions at prejunctional inhibitory A 1 and stimulatory A 2 adenosine receptors are evident in this preparation.