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THE EFFECTS OF SUBSTANCE P AND RELATED PEPTIDES ON α‐AMYLASE RELEASE FROM RAT PAROTID GLAND SLICES
Author(s) -
BROWN C.L.,
HANLEY M.R.
Publication year - 1981
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.1476-5381.1981.tb10451.x
Subject(s) - eledoisin , substance p , amylase , chemistry , endocrinology , agonist , medicine , pentapeptide repeat , potency , ed50 , receptor , extracellular , stimulation , in vivo , calcium , biochemistry , biology , peptide , in vitro , neuropeptide , enzyme , microbiology and biotechnology
1 The effects of substance P and related peptides on amylase release from rat parotid gland slices have been investigated. 2 Supramaximal concentrations (1 μ) of substance P caused enhancement of amylase release over the basal level within 1 min; this lasted for at least 40 min at 30°C. 3 Substance P‐stimulated amylase release was partially dependent on extracellular calcium and could be inhibited by 50% upon removal of extracellular calcium. 4 Substance P stimulated amylase release in a dose‐dependent manner with an ED 50 of 18 nM. 5 All C‐terminal fragments of substance P were less potent than substance P in stimulating amylase release. The C‐terminal hexapeptide of substance P was the minimum structure for potent activity in this system, having 1/3 to 1/8 the potency of substance P. There was a dramatic drop in potency for the C‐terminal pentapeptide of substance P or substance P free acid. Physalaemin was more potent than substance P (ED 50 = 7 nM), eledoisin was about equipotent with substance P (ED 50 = 17 nM), and kassinin less potent than substance P (ED 50 = 150 nM). 6 The structure‐activity profile observed is very similar to that for stimulation of salivation in vivo , indicating that the same receptors are involved in mediating these responses. 7 All the fragments of substance P tested were capable of eliciting a full amylase release response. This indicates that the apparent partial agonist action of the C‐terminal nonapeptide fragment on in vivo salivation is not explicable at the receptor level.