| Literature DB >> 2207254 |
A Shrier1, J R Clay, R M Brochu.
Abstract
The influence of relatively low concentrations of tetrodotoxin (TTX) on phase resetting of spontaneous activity of embryonic chick atrial heart cell aggregates by brief duration current pulses was investigated experimentally and theoretically. The maximal upstroke velocity, Vmax, of the spontaneous action potential was reduced by TTX in a concentration-dependent manner for [TTX] less than 10(-7) M. However, the beat rate was unaffected in this concentration range. Application of a depolarizing current pulse of brief duration during a critical region of the spontaneous cycle annihilated activity in some preparations exposed to [TTX] approximately 10(-7) M. These results were analyzed with the model of electrical activity described in the previous paper (Clay, J.R., R.M. Brochu, and A. Shrier. 1990. Biophys. J. 58:609-621) based on a tonic block of the INa channel by TTX with a dissociation constant, KD, of 50 nM.Entities:
Mesh：
Substances：
Year: 1990 PMID： 2207254 PMCID： PMC1281003 DOI： 10.1016/S0006-3495(90)82405-X
Source DB: PubMed Journal: Biophys J ISSN： 0006-3495 Impact factor: 4.033