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SOME PHARMACOLOGICAL EFFECTS OF p ‐CHLOROPHENYLALANINE UNRELATED TO TRYPTOPHAN HYDROXYLASE INHIBITION
Author(s) -
MARLEY E.,
WHELAN JENNIFER E.
Publication year - 1976
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.1476-5381.1976.tb07436.x
Subject(s) - methysergide , endocrinology , serotonin , medicine , histamine , ileum , tryptophan hydroxylase , eledoisin , substance p , acetylcholine , adrenal medulla , bronchoconstriction , chemistry , catecholamine , neuropeptide , serotonergic , receptor , asthma
1 Experiments were performed on a variety of tissues from different species to establish whether or not the properties of p ‐chlorophenylalanine methyl ester (PCPA) included a 5‐hydroxytryptamine (5‐HT)‐like action which might explain the soporific action of PCPA in chicks. 2 PCPA, like 5‐HT, contracted the rat fundal preparation (as did PCPA base), and in cats enhanced twitch tension of a lower limb flexor reflex, evoked adrenal medullary secretion and attenuated histamine‐induced gastric secretion; the effects on the rat fundal strip and the adrenal medulla were prevented by methysergide. 3 Like 5‐HT, PCPA elicited bronchoconstriction of guinea‐pig lungs, isolated or in vivo ; this was not prevented by methysergide but reduced by polyphloretin and by indomethacin. Perfusate collected from the lungs during PCPA‐induced bronchoconstriction and applied to superfused isolated tissues contained a substance with prostaglandin‐like activity. 4 In contrast, the effect of PCPA on the guinea‐pig isolated ileum differed from that of 5‐HT, since it relaxed the ileum when contracted by transmural excitation, by acetylcholine, histamine or 5‐HT and contracted the ileum on wash‐out.