title: Feedback Inhibition of Ca2+ Currents by Dopamine in Glomus Cells of the Carotid Body.
abstract: The effect of dopamine on the voltage-dependent ionic channels of enzymatically dispersed glomus cells from rabbit carotid bodies was studied. Whole-cell currents were recorded on isolation with patch electrodes and dopamine applied to the bath solution. Dopamine at nanomolar concentrations produced a reversible attenuation of the calcium current whereas sodium and potassium currents remained unaltered. Dopamine inhibition of Ca2+ current was observed in all cells tested (n=48) and at a saturating concentration (1 microM) the average reduction was of 40 +/- 6.5% (n=8). The effect of dopamine was probably caused by a decrease in the number of channels activatable on depolarization since it did not modify the voltage-dependent parameters of the current. These results indicate that dopamine, which is the major transmitter secreted by glomus cells, regulates further transmitter release by feedback inhibition of Ca2+ channels.
authors.affiliation: Departamento de Fisiología y Biofísica, Facultad de Medicina, Avenida Sánchez Pizjuán, 4, 41009 Sevilla, Spain.
authors.forename: A. R.
authors.initials: AR
authors.lastname: Benot
authors.forename: J.
authors.initials: J
authors.lastname: López-Barneo