Referenced in: none

Automatically associated channels: Kv10.1 , Slo1

Title: Organic calcium channel blockers generate the coexistence of two different types of action potentials in the same muscle membrane following chemical induction of excitability.

Authors: C Zuazaga, A Tatum, L Lizardi, J del Castillo

Journal, date & volume: Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol., 1991 , 99, 273-7

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1685397

Abstract
1. Following exposure to the sulfhydryl reagents known as alpha,beta-unsaturated carbonyl compounds, the ventroabdominal flexor muscles of the crustacean Atya lanipes, which are normally completely inexcitable, generate trains of overshooting calcium action potentials; the effects of organic calcium channel antagonists and potassium channel blockers on the chemically-induced trains of action potentials have been studied. 2. Verapamil and D600, at micromolar concentrations, elicit the appearance of slow, cardiac-like action potentials which coexist with the much faster chemically-induced calcium spikes, transforming the regular repetitive firing into a cyclic bursting pattern. 3. Bepridil (1 microM) decreases the frequency of firing of the action potentials, probably by increasing the threshold for the activation of a population of the chemically-induced calcium channels. 4. The potassium channel blockers, TEA (30-40 mM) and quinidine (100-200 microM), delayed the rate of repolarization of the chemically-induced action potentials; none of the potassium channel blockers, however, induced the appearance of repetitive spike activity.