Evaluation of the effect of crude extract of Datura innoxia on the cardiovascular action of detomidine in rabbits

Datura innoxia indigenous shrub in South Asia region belongs to the family Solanaceae which contains medicinal important alkaloids (hyoscine, atropine, hycosamine, etc). Thirty adult rabbits of mixed breed, male and female were pretreated with 0.1 mg/500 mg of crude extract (1% of dimethyl sulfoxide (DMSO) solution) and injected 5 min later with 0.01 mg/500 mg of detomidine (group A, n=15) or Saline (group B, n=15). Mean arterial pressure, measurements and electrocardiography were performed for 65 min. After injecting crude extract of D. innoxia, the heart rate was increased by 45 and 46.34% in groups A and B, respectively. Heart rate remained increased after the injection of detomidine returning to base line values after 15 min. No increase in the mean arterial pressure (MAP) was noted in group B rabbits. Crude extract shortened PR and QT interval in both groups but after detomidine, PR and QT interval were enlarged significantly at the end of the experiment. The second degree atrioventricular was blocked in two rabbits after 40 min only in group B. It was concluded that alkaloid present in D. innoxia prevented detomidine induced Bradycardia and might be useful during combination against the Bradycardia induced by alpha-2 agonist in the rabbits.