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Antagonist effects of seglitide (MK 678) at somatostatin receptors in guinea‐pig isolated right atria
Author(s) -
Dimech J.,
Feniuk W.,
Humphrey P.P.A.
Publication year - 1993
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.1476-5381.1993.tb13703.x
Subject(s) - somatostatin , carbachol , medicine , guinea pig , endocrinology , antagonist , agonist , somatostatin receptor , chemistry , receptor , competitive antagonist , receptor antagonist , biology
Somatostatin (SS) exerts a negative inotropic effect in isolated atria. Here we report that in guinea‐pig isolated right atria, seglitide, a potent cyclic hexapeptide somatostatin agonist, behaves as a competitive somatostatin receptor antagonist with pA 2 values against SS 14 , SS 25 and SS 28 , of 6.50 ± 0.40, 6.24 ± 0.08 and 6.09 ± 0.06, respectively. Seglitide had little or no effect on the negative inotropic action of carbachol or N 6 ‐cyclohexyladenosine. Our findings indicate that the receptor‐response coupling characteristics of guinea‐pig atria are such that in this preparation seglitide has low intrinsic activity and behaves specifically as a somatostatin receptor antagonist.