Summary
The effects of the two “specific bradycardic agents” AQ-A 39 and alinidine on the spontaneous electrical discharge rate of intact guinea-pig sinus node preparations were investigated. At high external K+-concentrations (10.8 and 16.2 mmol/l) the bradycardic effect of the two drugs was diminished or abolished. In contrast, the negative chronotropic effect of the reference compound verapamil (“Ca2+-antagonist”) was enhanced. These results show that the bradycardic effects of AQ-A 39 and alinidine are diminished in depolarized preparations, which makes it unlikely that in intact sinus node preparations the mechanism of action is the same as that of “Ca2+-antagonists”.
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Lillie, C., Kobinger, W. Decrease in bradycardic effect of AQ-A 39 and alinidine in guinea-pig sinoatrial node depolarized by high external K+-concentration. Naunyn-Schmiedeberg's Arch. Pharmacol. 328, 210–213 (1984). https://doi.org/10.1007/BF00512075
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DOI: https://doi.org/10.1007/BF00512075