Pharmacological effects of Azadirachta indica (neem) leaf extract on the ECG and blood pressure of rat.

Neem leaf alcoholic extract (NLE) was investigated for its effects on the ECG and blood pressure of rat. Intravenous administration of NLE (100, 300 and 1000 mg/kg) resulted in initial bradycardia followed by cardiac arrhythmia in rats. NLE produced a significant and dose-related fall in blood pressure which was immediate, sharp and persistent. Pre-treatment with either atropine or mepyramine failed to prevent the hypotensive effect of NLE.