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Angiotensin II‐induced stimulation of voltage‐dependent Ca2+ currents in an adrenal cortical cell line.
Author(s) -
Hescheler J.,
Rosenthal W.,
Hinsch K. D.,
Wulfern M.,
Trautwein W.,
Schultz G.
Publication year - 1988
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1988.tb02855.x
Subject(s) - biology , stimulation , angiotensin ii , line (geometry) , neuroscience , endocrinology , microbiology and biotechnology , medicine , geometry , mathematics , blood pressure
Biochemical studies suggest that stimulation of aldosterone secretion by angiotensin II involves activation of voltage‐dependent Ca2+ channels. We used an adrenocortical cell line (Y1) to study the effect of angiotensin II on transmembranous currents. The hormone (1 nM to 1 microM) caused depolarization of the plasma membrane (from −35 to 10 mV) and elicited repetitive action potentials. Using the whole‐cell clamp technique, we identified two types of voltage‐dependent Ca2+ currents which differed with respect to their threshold potential and time course of inactivation. Angiotensin II (1 nM to 1 microM) stimulated a slowly inactivating Ca2+ current on average up to 1.7‐fold whereas a fast inactivating Ca2+ current remained almost unaffected by the hormone. Ca2+ currents were not influenced by forskolin (1 microM) or intracellularly applied cAMP (50 microM). Pretreatment of cells with pertussis toxin abolished the hormonal stimulation of the slowly inactivating Ca2+ current but was without effect on control currents. The toxin ADP‐ribosylated a single membranous peptide of 40 kd Mr. An antiserum raised against a synthetic peptide corresponding to a region common to all sequenced alpha‐subunits of guanine nucleotide‐binding proteins (G‐proteins) and an antiserum raised against a peptide corresponding to a region of alpha‐subunits of Gi‐like G‐proteins reacted with membranous 40 kd peptides, whereas an antiserum raised against a synthetic peptide corresponding to a region specific for the alpha‐subunit of the G‐protein, G0, failed to recognize a peptide in the 39 to 40 kd region.(ABSTRACT TRUNCATED AT 250 WORDS)