[Effects of pentagastrin with intracerebroventricular injection on blood pressure and heart rate in rats].

Experiments were carried out on 84 artifially ventilated SD rats anaesthetized with urethane and immobilized with gallamine triethiodide. Injection of pentagastrin (G5) into the rat lateral ventricle resulted in a marked elevation in arterial blood pressure which reached its peak at 3 min (from 12.2 +/- 1.5 to 14.1 +/- 1.7 kPa) and also a significant increase in heart rate from 435 +/- 53.9 to 471.6 +/- 53.2 beats/min. This effect of G5 could be partially antagonized by injection of phentolamine (alpha-receptor antagonist, 10 micrograms) into the lateral ventricle, but not by propanolol (beta-receptor antagonist, 4 micrograms) or atropine (M-receptor antagonist, 4 micrograms). These findings indicate that the central effect of G5 on blood pressure and heart rate is partly mediated by alpha-receptor.