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CHARACTERIZATION OF THE ADRENOCEPTOR IN THE ISOLATED CREMASTER MUSCLE OF THE GUINEA‐PIG
Author(s) -
GUPTA R.S.,
KELKAR V.V.
Publication year - 1978
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.1476-5381.1978.tb06999.x
Subject(s) - practolol , isoprenaline , tolazoline , chemistry , orciprenaline , propranolol , medicine , endocrinology , phenylephrine , methoxamine , potency , cromakalim , phentolamine , guinea pig , salbutamol , pharmacology , stimulation , agonist , in vitro , biochemistry , blood pressure , receptor , asthma
1 Contractions of the isolated cremaster muscle of the guinea‐pig obtained in response to direct electrical stimulation were augmented by salbutamol, isoprenaline, adrenaline, noradrenaline and orciprenaline (in that order of potency), and by potassium chloride. Phenylephrine and xylometazoline had no effect. 2 The augmenting effect of isoprenaline on the twitch response was not altered by yohimbine or tolazoline, but was totally prevented by butoxamine, (‐) −1− (4‐nitrophenyl)‐2‐isopropylaminoethanol (INPEA), (±) ‐INPEA, sotalol, metalol and practolol; (+) ‐INPEA was much less effective. The augmenting effect of potassium was not altered by β‐adrenoceptor blockade. 3 The results are consistent with the view that the augmenting effect of the sympathomimetic agents is mediated through β 2 ‐type of adrenoceptor in the skeletal muscle fibres.