Ca2+ waves are organized among hepatocytes in the intact organ.
Nathanson, Michael H., Angela D. Burgstahler, Albert Mennone, Michael
B. Fallon, Carlos B. Gonzalez, and Juan C. Saez.
Liver Study Unit and Center for Cell Imaging, Yale University
School of Medicine, New Haven, CT 06520, USA, Department of
Physiology, Universidad Austral de Chile, Valdivia, Chile, and
Department of Physiological Sciences, Pontificia Universidad Catolica
de Chile, Santiago, Chile
APStracts 2:0052G, 1995.
Hormone-induced increases in cytosolic Ca2+ (Cai2+) begin as Cai2+
waves in cells isolated from most types of tissue (1,11), but whether
such waves actually occur in vivo is unknown. To investigate this, we
examined vasopressin-induced Cai2+ signals in hepatocytes within the
perfused rat liver. Using confocal fluorescence video microscopy, we
found that increases in Cai2+ began as waves which usually originated
in hepatocytes near central venules, then spread opposite to the
direction of blood flow, to hepatocytes near portal venules. We used
immunochemistry to determine that the liver vasopressin V1a receptor
is most concentrated among hepatocytes in the pericentral region,
providing the mechanism by which Cai2+ waves originate there.
Pericentral-to-periportal Cai2+ waves may direct peristaltic flow of
bile, since Cai2+ induces contraction of the apical pole of
hepatocytes, and since peristaltic contractions in liver also occur
in a pericentral-to-periportal direction. The organization of Cai2+
waves among cells in intact tissue may be a means by which an
integrative, organ-level response is provided in response to hormonal
stimuli.
Received 10 February 1995; accepted in final form 16 March 1995.
APS Manuscript Number G61-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 March 1995.