Interaction between Ca²⁺ channel blockers and isoproterenol on L‐type Ca²⁺ current in canine ventricular cardiomyocytes

Abstract

The results indicate that the action of isoproterenol is different in the presence of organic and inorganic Ca(2+) channel blockers. CoCl(2) and MnCl(2) were able to fully prevent the effect of isoproterenol on Ca(2+) current, while the organic Ca(2+) channel blockers failed to do so. This has to be born in mind when the effects of organic Ca(2+) channel blockers are evaluated either experimentally or clinically under conditions of increased sympathetic tone.

Remodelling of potassium currents underlies arrhythmic action potential prolongation under beta-adrenergic stimulation in hypertrophic cardiomyopathy

“…However, the recovery of both current amplitude and kinetics indicate a limited relevance within the time-frames considered, if at all present. Other works [10,18,60] using similar experimental protocols have also reported limited current rundown effects.…”

“…Test recordings in the presence of the drug were performed after >3 min from the beginning of drug exposure. Afterwards, ISO was washed out for >5 min to achieve a full washout of ISO, as reported in previous works [10,18], and measurements were repeated.…”

New Findings on the Effects of Tannic Acid: Inhibition of L‐Type Calcium Channels, Calcium Transient and Contractility in Rat Ventricular Myocytes

“…Moreover, TA caused hyperpolarizing shift of the steady‐state inactivation curve, which accelerates the voltage‐dependent inactivation of the Ca 2+ currents and prevents longer term free intracellular Ca 2+ increases. Nifedipine is a well‐known calcium channel blocker; Farkas et al found that nifedipine at 5 μM shifted the activation and inactivation curves of I Ca‐L toward the left direction (Farkas et al ., ). Because contractile activation is controlled by the Ca 2+ transient (i.e.…”