Format

Send to

Choose Destination
See comment in PubMed Commons below
J Physiol. 1978 Oct;283:197-209.

Inward calcium current in twitch muscle fibres of the frog.

Abstract

1. Voltage clamp experiments using the three micro-electrode voltage clamp technique were performed on sartorius muscles of the frog. 2. By blocking potassium currents with tetraethylammonium and replacing chloride ions with sulphate a slow inward current was detected. 3. The slow inward current is mainly carried by calcium, since it is abolished by cobalt and D-600, it depends on external calcium, and is not affected by removing external sodium or by tetrodotoxin (TTX). 4. The slow inward current has a mean threshold of -40 mV, reaches a mean maximum value at ca. 0 mV of 81 microamperemetercm-2 and has a mean reversal potential of +38 mV. 5. The calcium current is inactivated by the application of 2 sec conditioning prepulses according to a sigmoid curve with V(h) = -42 mV and k = 6.2 mV. 6. The slow time course of this calcium current makes it rather unlikely that it participates in contraction during a twitch, but it might be activated during long depolarizations as potassium contractures.

PMID:
309941
PMCID:
PMC1282773
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Support Center