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Study on some selective β‐adrenoreceptor blocking effects of 1‐(4‐nitrophenyl)‐1‐hydroxy‐2‐methyl isopropylaminoethane (α‐methyl INPEA)
Author(s) -
SOMANI PITAMBAR
Publication year - 1969
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.1476-5381.1969.tb08499.x
Subject(s) - chemistry , blockade , vasodilation , medicine , pharmacology , endocrinology , stereochemistry , receptor , biochemistry , biology
1 . The effect of methyl substitution in the α‐carbon position of the ethanolamine side chain of INPEA was investigated on its β‐adrenoreceptor blocking activity in the isolated turtle heart and anaesthetized cats. 2 . In the turtle heart preparation, the pA 2 value for erythro‐α‐methyl INPEA was 5·3, as compared with 6·9 for INPEA, while threo‐α‐methyl INPEA was extremely weak and its pA 2 value could not be determined. 3 . In the intact cat experiments, α‐methyl INPEA produced a competitive blockade of the peripheral vasodilator effect of isoprenaline in doses ranging from 5 to 20 mg/kg. However, this agent had a minimal effect on the cardiac stimulant effect of the catecholamine. 4 . These results are consistent with the hypothesis that the β‐adrenoreceptors comprise a family of nonhomogeneous receptors and a selective blockade of only some, but not all, responses mediated through their activation can be achieved by specific molecular modification of the β‐adrenoreceptor blocking agents.