Abstract: ObjectiveTo study the influences of "dose-time-efficacy" relationship on normal rat blood pressure from a single administration of Aconite water extract in pharmacopoeia dose. MethodsThe 5 different Aconite water extract doses of 1.35, 1.08, 0.81, 0.54, 0.27 g·kg-1 (which correspond in the pharmacopoeia Aconite dose 15, 12, 9, 6, 3 g) were prepared, and rats were given Aconite water extract by gavage respectively. Changes of rat blood pressure according to different time and dose were observed in 15, 30, 60, 90, 120 min respectively by BP-100A automatic non-invasive blood pressure measurement system. And the ED50 of Aconite water extract was tested. ResultsThe "dose-time-efficacy" relationship showed that: compared with normal group, the changes of blood pressure in rat were increasing marks from 15 min to 120 min. The systolic pressure in five dose groups hit the peak in 30 min and Aconite water extract high dose (1.35g·kg-1) is the largest. In 120 min, the systolic pressure in five dose groups were basically back to the front of the gavage. The diastolic blood pressure of rats by Aconite water extract was increasing marks from 15 min to 120 min to some extent. The ED50 and its 95% confidence limit of Aconite water extract were 0.1474 (2.3411~0.3482) g·kg-1. ConclusionAconite water extract in the pharmacopoeia dose range elevates rats systolic blood pressure, and there is a certain relationship of "dose-time-efficacy": higher dose, greater pressor effects and longer action time.

Key words: Aconitum carmichaeli Debx., water extract, blood pressure, dose-time- efficacy