The relationship of intracellular free calcium activity to amylase secretion in substance P- and isoprenaline-stimulated rat parotid acini.
The relationship between intracellular free calcium activity ([Ca2+]i) and stimulated amylase secretion was investigated in rat parotid acini by measuring the effects of substance P methyl ester and isoprenaline on quin2 fluorescence and amylase release. Although both of these drugs evoked concentration-dependent increases in [Ca2+]i and amylase release, the tachykinin had a greater effect on [Ca2+]i while the catecholamine was the more effective secretagogue. Whereas isoprenaline exerted equipotent effects on amylase secretion and [Ca2+]i, the dose-response relationship for stimulation of secretion by substance P was dissociated by three orders of magnitude to the right of that for elevation of [Ca2+]i by this peptide. It is concluded that these data do not support the hypothesis that substance P-stimulated amylase secretion is mediated solely through an increase in [Ca2+]i and that other second-messengers may be involved in mediation of this secretory response.
Arkle
S
S
Portsmouth Polytechnic School of Pharmacy & Biomedical Sciences, Portsmouth, U.K.
Michalek
R
R
Templeton
D
D
D000634:Aminoquinolines; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D015290:Second Messenger Systems / Q000187:drug effects; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D013373:Substance P; C033611:substance P, methyl ester-; D000681:Amylases; D007545:Isoproterenol; C035739:Quin2; D002118:Calcium