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THE EFFECTS OF L‐ALANINE AND ACETYLCHOLINE ON MEMBRANE POTENTIAL, 45 Ca 2+ AND 86 Rb + EFFLUX AND AMYLASE SECRETION IN THE ISOLATED MOUSE PANCREAS
Author(s) -
Singh J.,
Petersen O. H.
Publication year - 1984
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1984.sp002839
Subject(s) - acetylcholine , depolarization , alanine , efflux , amylase , ouabain , membrane potential , chemistry , secretion , medicine , acinar cell , endocrinology , biophysics , biochemistry , biology , pancreas , enzyme , sodium , amino acid , organic chemistry
A comparative study was made of the effects of acetylcholine (ACh) and the neutral amino acid L‐alanine on membrane potential, 45 Ca 2+ and 86 Rb + fractional efflux, and amylase secretion in segments of the isolated mouse pancreas. Both ACh and L‐alanine evoked similar dose‐dependent depolarizations of pancreatic acinar cells. ACh, but not L‐alanine, caused a marked reduction in input resistance and evoked electrical uncoupling of acinar cells at high concentrations. Measurements of 45 Ca 2+ release from pre‐labelled tissue showed that ACh increased the fractional efflux of 45 Ca 2+ whereas L‐alanine had no such effect. Both ACh and L‐alanine stimulated the release of 86 Rb + from pre‐labelled tissues. The L‐alanine‐evoked 86 Rb + efflux was markedly reduced by pre‐treatment with 10 –3 M ouabain which had no effect on the ACh‐induced response. L‐alanine had no significant effect on amylase secretion whereas ACh elicited a marked increase in amylase output. These results show that although both ACh and L‐alanine evoke depolarization of the pancreatic acinar cell membrane, the mechanisms underlying their actions on the cells are different.