Protein kinase c modulates natriuretic peptide receptors in
astroglial cultures from rat brain.
Paulding, Waltke R., and Colin Sumners.
Dept. of Physiology, College of Medicine, University of Florida,
Gainesville, FL 32610
APStracts 2:0329C, 1995.
We determined previously that astroglia cultured from newborn rat
brain contain both guanylyl cyclase coupled and ANP-C natriuretic
peptide receptors. Here, we investigated the effects of the protein
kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) on
these receptor subtypes in cultured astroglia, in order to understand
the intracellular processes involved in the modulation of natriuretic
peptide receptors in these cells. PMA (10 nM -1?_M; 15 min - 24 hr)
treatment elicited a time- and concentration-dependent decrease in
the numbers of 125I-atrial natriuretic peptide (125I-ANP) specific
binding sites, which was inhibited by the PKC antagonist
staurosporine (500 nM). Furthermore, PMA (100 nM, 2 or 24 hr)
treatment elicited a significant decrease in the specific binding of
125I-des Cys Cys ANP, an ANP-C receptor selective ligand. PMA (10 nM
- 1?_M; 30 min) treatment also significantly decreased ANP (100 nM)
-stimulated cyclic GMP levels in cultured astroglia, an effect
unmodified by phosphodiesterase inhibition. These data indicate that
PKC modulates both guanylyl cyclase coupled and ANP-C natriuretic
peptide receptors in cultured astroglia.
Received 20 June 1995; accepted in final form 5 September 1995.
APS Manuscript Number C393-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.