Biophysical Journal 70: 806-812 (1996)
© 1996 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cloues, R Articles by Marrion, N V Search for Related Content PubMed PubMed Citation Articles by Cloues, R Articles by Marrion, N V

Conduction properties of the M-channel in rat sympathetic neurons.

Vollum Institute, Oregon Health Sciences University, Portland 97201, USA. clouesr@ohsu.edu

ABSTRACT

We have investigated the conduction properties of the M-channel in rat superior cervical ganglion neurons. Reversal potentials measured under bi-ionic conditions yielded a permeation sequence of Tl > K > Rb > Cs > NH4 > Na. Slope conductances gave a conductance sequence of K > Tl > NH4 > Rb > Cs. M-current was shown to exhibit a number of features atypical of potassium channels. First, the conduction of monovalent cations relative to K was very low. Second, the nature of the permeant ion did not affect the deactivation kinetics. Third, M-current did not exhibit anomalous mole-fraction behavior, a property suggestive of a multi-ion pore. Finally, external Ba, which is a blocker of M-current, showed a preferential block of outward current and had much less effect on inward current. The permeability sequence of the M-channel is very similar to other K-selective channels, implying a high degree of conservation in the selectivity filter. However, other conduction properties suggest that the pore structure outside of the selectivity filter is very different from previously cloned potassium channels.

This article has been cited by other articles:

				D. L. Prole and N. V. Marrion Ionic Permeation and Conduction Properties of Neuronal KCNQ2/KCNQ3 Potassium Channels Biophys. J., March 1, 2004; 86(3): 1454 - 1469. [Abstract] [Full Text] [PDF]

				M. E. Schnee and B. S. Brown Selectivity of Linopirdine (DuP 996), a Neurotransmitter Release Enhancer, in Blocking Voltage-Dependent and Calcium-Activated Potassium Currents in Hippocampal Neurons J. Pharmacol. Exp. Ther., August 1, 1998; 286(2): 709 - 717. [Abstract] [Full Text]

				B. C. Schroeder, M. Hechenberger, F. Weinreich, C. Kubisch, and T. J. Jentsch KCNQ5, a Novel Potassium Channel Broadly Expressed in Brain, Mediates M-type Currents J. Biol. Chem., July 28, 2000; 275(31): 24089 - 24095. [Abstract] [Full Text] [PDF]