Atrial natriuretic peptide differentially modulates T- and L-type calcium channels.
Atrial natriuretic peptide (ANP) inhibits the secretion of aldosterone stimulated by any of these major physiological agonists: angiotensin II, adrenocorticotropic hormone, or K+. The stimulatory actions of each of these agonists depend on calcium influx through voltage-dependent calcium channels. Because two types of calcium channels have been previously described in bovine glomerulosa cells (T- and L-type), the patch-clamp technique was used to evaluate the effect of ANP on each voltage-dependent calcium channel type. ANP was found to differentially modulate these two channel types, stimulating L-current while inhibiting T-current. Inhibition of T-current resulted from a shift in the voltage dependence of inactivation to more negative potentials within the physiological range. These results indicate that the ANP-induced inhibition of aldosterone secretion may be partially mediated via a reduction of the calcium current through T-type channels.
McCarthy
R T
RT
Miles Institute for Preclinical Pharmacology, West Haven, Connecticut 06516.
Isales
C M
CM
Bollag
W B
WB
Rasmussen
H
H
Barrett
P Q
PQ
D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004594:Electrophysiology; D009994:Osmolar Concentration
D015220:Calcium Channels; D009320:Atrial Natriuretic Factor