Abstract
Investigations on the influence of nicotine and acetylcholine on isolated 30 frog and 10 rabbit hearts stopped with 0.5ml of 50% alcohol and 0.1 to 0.5ml of 0.5 to 1% cortisone, hydrocortisone and prednisolone indicated that 0.1 to 3ml of 10-4Gm/ml of nicotine restarted the stopped hearts. Acetylcholine in a dose of 0.1 to 3ml of 10-7 to 10-4Gm/ml was less effective in restarting the stopped hearts. Prior or simultaneous administration of nicotine or acetylcholine prevented occurrence of cardiac asystole with alcohol and glucocorticoids or cut short its duration. Prior administration of alcohol modified the action of nicotine. Catecholamine release from cardiac neural elements does not appear to be involved in antiasystolic action of nicotine and acetylcholine. It has been suggested that asystolic and antiasystolic actions may be coupled with a common receptor or enzyme system through which drugs produce biphasic and opposite effects depending upon concentration.
