Properties of whole cell currents in isolated olfactory neurons from the chilean toad Caudiverbera caudiverbera
Delgado, R.; Labarca, P.
American Journal of Physiology 264(6 Pt 1): C1418-C1427
1993
ISSN/ISBN: 0002-9513 PMID: 8333496 Document Number: 416333
Isolated olfactory neurons from the chilean to a Caudiverbera caudiverbera were found to possess a same set of currents. Outward currents, made of a delayed rectifier and a Ca-2+-dependent component, were blocked by replacing K+ by Cs+ in the patch pipette, in the presence of millimolar concentrations of tetraethylammonium and 4-aminopyridine in the external solution. Inward currents were made of a transient and a maintained component. The transient was abolished in the absence of external Na+ and was blocked by tetrodotoxin, with an apparent dissociation constant (K-D app) of 25.4 +- 0.3 nM. The maintained inward currents were suppressed on removing external Ca-2+, could be carried also by Ba-2+, and were selectively blocked by Cd-2+ (K-D app = 3.2 +- 1.3 mu-M). A variety of agents found to block the maintained Ca-2+ inward currents, including Co-2+ and Ni-2+, at millimolar concentrations, and nifedipine, verapamil, amiloride, and the amiloride analogue benzamil, at micromolar concentrations, were also effective in either modifying the gating of, or in blocking, the transient inward currents.