Temporal and spatial heterogeneities of intracellular ca2+
signalling - their mechanisms and roles in the physiology of the
gastrointestinal secretory cells.
Toescu, Emil C.
Dept. of Physiology, School of Medicine,
APStracts 2:0092G, 1995.
In the cells of the gastrointestinal tract, as in most other types of
cells, many of the fundamental cellular functions are mediated by
increases of intracellular calcium. These increases are mediated
primarily by elevations of the inositol 1,4,5-trisphosphate (InsP3)
which, in turn, are a consequence of the activation of specific
plasma membrane receptors. Extensive investigations of these
intracellular processes in the last few years revealed the
complexities of Ca2+ signalling. The extreme heterogeneity of Ca2+
signalling, which is manifest by variations both in the time-course
and the spatial distribution of these signals, forms the central
theme of this review. On the basis of the available information the
various intracellular mechanisms which allow the manifestation of
this heterogeneity are discussed. It is argued that these variations
in Ca2+ response are the result not only of the existence of
multiple, complex mechanisms participating in the generation and
maintenance of the agonist-evoked Ca2+ signal but also of the
existence of various isoforms for almost each of the main molecules
involved in signalling and the concomitant participation of many
intracellular modulators.
Received 25 April 1995; accepted in final form 10 May 1995.
APS Manuscript Number G196-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 16 May 1995.