Modulation of basal intracellular calcium by inverse agonists and phorbol myristate acetate in rat‐1 fibroblasts stably expressing α1d‐adrenoceptors
- 29 January 1999
- journal article
- Published by Wiley in FEBS Letters
- Vol. 443 (3), 277-281
- https://doi.org/10.1016/s0014-5793(98)01738-4
Abstract
In rat-1 fibroblasts stably expressing α1d-adrenoceptors BMY 7378, phentolamine, chloroethylclonidine and 5-methyl urapidil decreased basal [Ca2+]i. WB 4101 induced a very small effect on this parameter but when added before the other antagonists it blocked their effect. All these agents inhibited the action of norepinephrine. Phorbol myristate acetate also blocked the effect of norepinephrine and decreased basal [Ca2+]i. Staurosporine inhibited these effects of the phorbol ester. Our results suggest that: (1) α1d-adrenoceptors exhibit spontaneous ligand-independent activity, (2) BMY 7378, phentolamine, chloroethylclonidine and 5-methyl urapidil act as inverse agonists and (3) protein kinase C activation blocks spontaneous and agonist-stimulated α1d-adrenoceptor activity.Keywords
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