Inward rectification in rat olfactory receptor neurons.
Inwardly rectifying currents in enzymically dissociated olfactory receptor neurons of rat were studied by using patch-clamp techniques. Upon hyperpolarization to membrane potentials more negative than -100 mV, small inward-current relaxations were observed. Activation was described by a single exponential with a time constant that decreased e-fold for a 21 mV hyperpolarization. The current was not reduced by the external application of 5 mM Ba2+, but was abolished by the addition of 5 mM Cs+ to the bath solution. Increasing the external K+ concentration ([K+]o) to 25 mM dramatically enhanced the current without affecting the voltage range or the kinetics of activation. In 25 mM [K+]o, tail currents reversed at -26 mV, significantly more positive than the K+ equilibrium potential of -44 mV. These characteristics are consistent with those of a mixed Na+/K+ inward rectification that has been reported in several types of neuronal, cardiac and smooth muscle cells. The current may contribute to controlling cell excitability during the response to some odorants.
School of Physiology and Pharmacology, University of New South Wales, Kensington, Australia.
J W
JW
Lynch
P H
PH
Barry
D000200:Action Potentials; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D002586:Cesium / Q000494:pharmacology; D004848:Epithelium / Q000502:physiology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000502:physiology*; D009666:Nose / Q000294:innervation*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011984:Sensory Receptor Cells / Q000502:physiology*; D012903:Smell
D002586:Cesium; D011188:Potassium