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Gastroenterology. 1999 Dec;117(6):1363-9.

L-Type calcium channels in enterochromaffin cells from guinea pig and human duodenal crypts: an in situ study.

Author information

1
Section of Gastrointestinal Science, Clinical Division I, University of Manchester, Salford, England.

Abstract

BACKGROUND & AIMS:

This study has investigated stimulus-secretion coupling of enterochromaffin cells by studying the cellular location and function of voltage-gated Ca(2+) channels within small intestinal crypts.

METHODS:

Digital fluorescence imaging and electrochemical detection were used to measure intracellular Ca(2+) responses and serotonin (5-hydroxytryptamine [5-HT]) secretion in intact crypts isolated from guinea pig and human duodenum.

RESULTS:

In fluo-3-loaded crypts, electrical depolarization with high K(+) solution increased cytosolic free [Ca(2+)] only in single cells subsequently identified by immunocytochemistry as enterochromaffin cells. In guinea pig enterochromaffin cells, the L-type Ca(2+) channel agonist FPL 64176 (3 micromol/L) did not change resting intracellular [Ca(2+)] but potentiated the depolarization-evoked increase in [Ca(2+)] (298 +/- 72 nmol/L) by 19 +/- 3-fold. In the majority of human enterochromaffin cells, FPL 64176 alone increased resting [Ca(2+)] by 423 +/- 171 nmol/L. Secretion studies in guinea pig crypts showed that high K(+) and FPL 64176 caused a 12-fold increase in 5-HT release. Noradrenaline caused increases in both enterochromaffin cell [Ca(2+)] and 5-HT release.

CONCLUSIONS:

Using this approach, we have found that in duodenal crypts, enterochromaffin cells, but not other epithelial cells, contain L-type voltage-gated Ca(2+) channels involved in regulating 5-HT secretion. These data have implications for the pharmacological control of intestinal disorders involving enterochromaffin cell dysfunction.

PMID:
10579977
DOI:
10.1016/s0016-5085(99)70286-6
[Indexed for MEDLINE]

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