z-logo
Premium
Receptor‐oriented intercellular calcium waves evoked by vasopressin in rat hepatocytes
Author(s) -
Tordjmann Thierry,
Berthon Brigitte,
Jacquemin Edith,
Clair Caroline,
Stelly Nicole,
Guillon Gilles,
Claret Michel,
Combettes Laurent
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.16.4695
Subject(s) - vasopressin , biology , vasopressin receptor , intracellular , receptor , arginine vasopressin receptor 2 , arginine vasopressin receptor 1b , calcium in biology , microbiology and biotechnology , inositol , endocrinology , medicine , biophysics , biochemistry , antagonist
Agonist‐induced intracellular calcium signals may propagate as intercellular Ca 2+ waves in multicellular systems as well as in intact organs. The mechanisms initiating intercellular Ca 2+ waves in one cell and determining their direction are unknown. We investigated these mechanisms directly on fura2‐loaded multicellular systems of rat hepatocytes and on cell populations issued from peripheral (periportal) and central (perivenous) parts of the hepatic lobule. There was a gradient in vasopressin sensitivity along connected cells as demonstrated by low vasopressin concentration challenge. Interestingly, the intercellular sensitivity gradient was abolished either when D‐myo‐inositol 1,4,5‐trisphosphate (InsP 3 ) receptor was directly stimulated after flash photolysis of caged InsP 3 or when G proteins were directly stimulated with AlF 4− . The gradient in vasopressin sensitivity in multiplets was correlated with a heterogeneity of vasopressin sensitivity in the hepatic lobule. There were more vasopressin‐binding sites, vasopressin‐induced InsP 3 production and V1a vasopressin receptor mRNAs in perivenous than in periportal cells. Therefore, we propose that hormone receptor density determines the cellular sensitivity gradient from the peripheral to the central zones of the liver cell plate, thus the starting cell and the direction of intercellular Ca 2+ waves, leading to directional activation of Ca 2+ ‐dependent processes.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here