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Modulation of basal intracellular calcium by inverse agonists and phorbol myristate acetate in rat‐1 fibroblasts stably expressing α 1d ‐adrenoceptors
Author(s) -
Garcı́a-Sáinz J.Adolfo,
Torres-Padilla Marı́a Elena
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01738-4
Subject(s) - phentolamine , staurosporine , protein kinase c , inverse agonist , endocrinology , medicine , agonist , chemistry , phorbol , norepinephrine , receptor , biology , biochemistry , kinase , stimulation , dopamine
In rat‐1 fibroblasts stably expressing α 1d ‐adrenoceptors BMY 7378, phentolamine, chloroethylclonidine and 5‐methyl urapidil decreased basal [Ca 2+ ] 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 [Ca 2+ ] i . Staurosporine inhibited these effects of the phorbol ester. Our results suggest that: (1) α 1d ‐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 α 1d ‐adrenoceptor activity.