PT  - JOURNAL ARTICLE
AU  - N Aiyar
AU  - P Nambi
AU  - M Whitman
AU  - F L Stassen
AU  - S T Crooke
TI  - Phorbol ester-mediated inhibition of vasopressin and beta-adrenergic responses in a vascular smooth muscle cell line.
DP  - 1987 Feb 01
TA  - Molecular Pharmacology
PG  - 180--184
VI  - 31
IP  - 2
4099  - http://molpharm.aspetjournals.org/content/31/2/180.short
4100  - http://molpharm.aspetjournals.org/content/31/2/180.full
SO  - Mol Pharmacol1987 Feb 01; 31
AB  - We have reported previously that in the vascular smooth muscle cell line A-10 (ATCC CRL 1476), vasopressin stimulated phosphatidylinositol turnover Ca2+ efflux and inhibited isoproterenol-stimulated cAMP accumulation. Here we report that pretreatment of these cells with phorbol dibutyrate, an activator of protein kinase C, attenuated the responses to vasopressin and isoproterenol. This effect was concentration dependent and could be observed after pretreatment for 2 min. 4 alpha Phorbol 12,13-didecanoate, which does not activate protein kinase C, did not attenuate the responses. These data suggest that activation of protein kinase C by phorbol dibutyrate attenuates the responses of vascular smooth muscle cells to isoproterenol and vasopressin. Although phorbol ester did not affect [3H]-8-arginine vasopressin binding to intact cells, it appeared to uncouple vasopressin receptors from guanine nucleotide-binding protein.