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α 1 ‐Adrenergic stimulation of Cl − efflux in isolated brown adipocytes
Author(s) -
Dasso Leonardo,
Connolly Eamonn,
Nedergaard Jan
Publication year - 1990
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 - 10.1016/0014-5793(90)80144-8
Subject(s) - stimulation , efflux , adrenergic , chemistry , endocrinology , medicine , biology , biochemistry , receptor
Unidirectional 36 Cl − efflux from preloaded isolated brown adipocytes was studied. A norepinephrine‐stimulated 36 Cl − efflux pathway was found which approximately doubled the rate of 36 Cl − efflux from the cells. The response to norepinephrine was fully inhibited by the α 1 ‐adrenergic antagonist prazosin, but was unaffected by the β‐adrenergic antagonist propranolol, showing that norepinephrine stimulated the 36 Cl − efflux pathway via the α 1 ‐adrenoceptor. The stimulation of 36 Cl − efflux could not be mimicked by the Ca 2+ ionophore A23187, indicating that the effect was not mediated by elevation of the intracellular Ca 2+ level. It is concluded that brown fat cells possess a specific mechanism for α 1 ‐adrenergic stimulation of Cl − efflux. The possibility is discussed that this Cl − efflux pathway could be the basis for the early α‐adrenergic depolarization seen in brown fat cells.