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Non‐specific actions of the non‐peptide tachykinin receptor antagonists, CP‐96, 345, RP 67580 and SR 48968, on neurotransmission
Author(s) -
Wang ZunYi,
Tung Steven R.,
Strichartz Gary R.,
Håkanson Rolf
Publication year - 1994
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.1476-5381.1994.tb14041.x
Subject(s) - tachykinin receptor , medicine , endocrinology , receptor , substance p , neuropeptide , biology , chemistry
1 Three non‐peptide tachykinin receptor antagonists, CP‐96,345, RP 67580 and SR 48968, were found to inhibit the electrically‐evoked, tachykinin‐mediated contractile responses of the rabbit iris sphincter in a concentration‐dependent fashion; the pIC 50 values were 5.6 ± 0.01, 5.4 ± 0.07 and 4.8 ± 0.03, respectively. 2 These antagonists also inhibited the electrically‐evoked, parasympathetic response of the rabbit iris sphincter and the sympathetic response of the guinea‐pig vas deferens in a concentration‐dependent manner; the pIC 50 values were 0.3–1.2 log units lower than those recorded for the tachykinin‐mediated responses. 3 Two local anaesthetics, bupivacaine and oxybuprocaine, were also found to inhibit the tachykinin‐mediated, cholinergic and sympathetic contractile responses in these tissues in a concentration‐dependent manner; the concentration ranges for producing the inhibition were similar to those of the non‐peptide tachykinin receptor antagonists. 4 On the sciatic nerves of frogs, the tachykinin receptor antagonists inhibited action potentials in a concentration‐dependent manner; the potency of the three drugs was similar to that of bupivacaine. 5 Our results suggest that, in addition to blocking tachykinin receptors, the non‐peptide tachykinin receptor antagonists, CP‐96,345, RP 67580 and SR 48968, may exert non‐specific inhibitory effects on neurotransmission.