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Pancreatic acinar cells: acetylcholine‐induced membrane depolarization, calcium efflux and amylase release
Author(s) -
Matthews E. K.,
Petersen O. H.,
Williams J. A.
Publication year - 1973
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1973.sp010367
Subject(s) - depolarization , acetylcholine , efflux , chemistry , amylase , acinus , acinar cell , biophysics , endocrinology , intracellular , membrane potential , medicine , calcium , biochemistry , biology , pancreas , enzyme , organic chemistry
1. The effects of acetylcholine upon the output of amylase, Ca 2+ efflux and membrane potential of pancreatic acinar cells have been measured in segments of mouse pancreas superfused in vitro . 2. Amylase output was measured continuously using an on‐line automated fluorimetric method; Ca 2+ efflux was monitored by measuring the release of 45 Ca 2+ from pre‐labelled tissue; and intracellular recordings of acinar transmembrane potentials were obtained with glass micro‐electrodes. In some experiments membrane potentials, and in others 45 Ca 2+ efflux, were measured concomitantly with amylase release. 3. Acetylcholine depolarized the acinar cells, increased tissue 45 Ca 2+ efflux and raised amylase output, each with a similar dose‐dependence, i.e. a maximal response at 10 −5 M , threshold ⋜ 10 −8 M , and ED 50 values of 0·7 × 10 −7 M , 0·5 × 10 −7 M , and 2 × 10 −7 M for depolarization, amylase release, and 45 Ca 2+ efflux, respectively. 4. In response to acetylcholine both depolarization and 45 Ca 2+ efflux preceded or coincided with the increase in amylase output. 5. Acetylcholine 10 −5 M and [K] 0 47 m M were without effect on 45 Ca 2+ efflux in the presence of atropine (3 × 10 −6 M ) but pancreozymin (0·3 u./ml.) still elicited a marked increase in 45 Ca 2+ release. 6. These results suggest that the stimulatory action of acetylcholine on the pancreatic acinar cell involves, sequentially, a specific receptor‐activated increase in membrane permeability, depolarization, Ca 2+ mobilization and amylase release. These events are discussed in relation to the integrated mechanism of stimulus‐secretion coupling.