Korean J Physiol Pharmacol.  2005 Oct;9(5):269-273.

Two Types of Voltage-activated Calcium Currents in Goldfish Horizontal Cells

Affiliations
  • 1Department of Physics & Biophysics, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea. cjung@catholic.ac.kr

Abstract

In horizontal cells (HCs) that were freshly dissociated from goldfish retina, two types of voltage- dependent calcium currents (ICa) were recorded using a patch-clamping configuration: a transient type current and a sustained type current. The cell was held at -40 mV, and the prepulse step of -90 mV was applied before command pulse between -65 and +55 mV. The transient Ca2+ current was activated by depolarization to around -50 mV from a prepulse voltage of -90 mV lasting at least 400 ms and reached a maximal value near -25 mV. On the other hand, the sustained Ca2+ current was induced by pre-inactivation for less than 10 ms duration. Its activation started near -10 mV and peaked at +20 mV. Co2+ (2 mM) suppressed both of these two components, but nifedipine (20microM), L-type Ca2+ channel antagonist, blocked only the sustained current. Based on the activation voltage and the pharmacological specificity, the sustained current appears to be similar to L-type ICa and the transient type to T-type ICa. This study is the first to confirm that transient type ICa together with the sustained one is present in HCs dissociated from goldfish retina.

Keyword

Horizontal cell; Sustained calcium current; Transient calcium current; Goldfish; Whole-cell Patch-Clamp; Retina

MeSH Terms

Calcium*
Goldfish*
Hand
Nifedipine
Retina
Sensitivity and Specificity
Calcium
Nifedipine
Full Text Links
  • KJPP
Actions
Cited
CITED
export Copy
Close
Share
  • Twitter
  • Facebook
Similar articles
Copyright © 2024 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: koreamed@kamje.or.kr