QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal 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 Brezden, B. Articles by Gardner, D. Search for Related Content PubMed Articles by Brezden, B. Articles by Gardner, D.

Journal of Experimental Biology, Vol 150, Issue 1 187-203, Copyright © 1990 by Company of Biologists

JOURNAL ARTICLES

Non-voltage-gated calcium channels in snail heart ventricle cells

BL Brezden and DR Gardner
Ottawa-Carleton Institute of Biology, Carleton University, Ontario, Canada.

1. Two recently identified channel types in Lymnaea stagnalis heart muscle cells were shown to conduct Na+ in the absence of extracellular Ca2+. They did not appear to be 'voltage-gated' as they were not activated by voltage. Also, they remained active over a wide range of membrane potentials. However, they were weakly 'voltage-sensitive' as their activity usually tended to increase with depolarization. The weak voltage-sensitivity and similarity to other non-voltagegated Ca2+ channels suggested that one or both of these channels may be receptor-operated Ca2+ channels. 2. One of the two channels had a slope conductance of 15 pS. The other appeared to have at least two subconductance states with slope conductances of 50 and 72pS. Both these conductance states had very similar open dwell-time constants and identical reversal potentials. The open dwell-time constants of both conductance states were not affected by voltage, suggesting that the channels' weak voltage-sensitivity was mediated by one of the closed states. 3. With divalent cations in the patch pipette, non-voltage-gated Ba2+ and Ca2+ currents were also detected. The Ba2+ conductance (12pS) was similar to the Ca2+ conductance (11pS).

This article has been cited by other articles:

				M. S. Yeoman, B. L. Brezden, and P. R. Benjamin LVA and HVA Ca2+ Currents in Ventricular Muscle Cells of the Lymnaea Heart J Neurophysiol, November 1, 1999; 82(5): 2428 - 2440. [Abstract] [Full Text] [PDF]

				B. L. Brezden, M. S. Yeoman, D. R. Gardner, and P. R. Benjamin FMRFamide-Activated Ca2+ Channels in Lymnaea Heart Cells Are Modulated by "SEEPLY," a Neuropeptide Encoded on the Same Gene J Neurophysiol, April 1, 1999; 81(4): 1818 - 1826. [Abstract] [Full Text] [PDF]