Volume-sensitive Cl- current in bovine adrenocortical cells: comparison with the ACTH-induced Cl- current.

In a previous study performed on zona fasciculata (ZF) cells isolated from calf adrenal glands, we identified an ACTH-induced Cl- current involved in cell membrane depolarization. In the present work, we describe a volume-sensitive Cl- current and compare it with the ACTH-activated Cl- current. Experiments were performed using the whole-cell patch-clamp recording method, video microscopy and cortisol-secretion measurements.

ACTH-induced Cl(-) current in bovine adrenocortical cells: correlation with cortisol secretion.

ACTH has been shown to depolarize bovine adrenal zona fasciculata cells by inhibiting a K(+) current. The effects of this hormone on such cells have been reexamined using perforated and standard patch recording methods. In current clamp experiments, ACTH (10 nM) induced a membrane depolarization to -36 +/- 1 mV (n = 56), which was mimicked by forskolin (10 microM) or by 8-(4-chlorophenylthio)-cAMP (8 mM).

Characterization of Na/Ca exchange in plasmalemmal vesicles from zona fasciculata cells of the bovine adrenal gland.

The presence of an Na/Ca exchange system in fasciculata cells of the bovine adrenal gland was tested using isolated plasmalemmal vesicles. In the presence of an outwardly Na(+) gradient, Ca(2+) uptake was about 2-fold higher than in K(+) condition. Li(+) did not substitute for Na(+) and 5 mM Ni(2+) inhibited Ca(2+) uptake.

Opposite effects of halothane on guinea-pig ventricular action potential duration.

Halothane protects the heart against the reperfusion injury observed after an ischemia. In ischemic or anoxic conditions, a large ATP-sensitive K(+) (K(ATP)) conductance is supposed to provide an endogenous protection to the myocardium. In this study, we tested the possibility that halothane acted by modulating this conductance.

Two types of pharmacologically distinct Ca(2+) currents with voltage-dependent similarities in zona fasciculata cells isolated from bovine adrenal gland.

Voltage-activated Ca(2+) currents, in zona fasciculata cells isolated from calf adrenal gland, were characterized using perforated patch-clamp recording. In control solution (Ca(2+): 2.5 mm) a transient inward current was followed, in 40% of the cells, by a sustained one.