Study of the effect of prostaglandin F2 and its synthetic methyl analomuscular transmission and reflex activity in anaesthetised dogs

ABSTRACT

The intravenous injection of prostaglandin F[2] alpha a [PGF[2] alpha in doses 1 of 10-20 ug/kg body weight into anaesthetized dogs resulted in rise of arterial blood pressure. The hypertensive effect ranged between 25-46 percent of the preinjection level. Tachyphylaxis was demonstrated in several experiments. The blood pressure records showed periods of tachycardia. Also PGF[2] alpha a in the above mentioned doses produced significant inhibition of the knee jerk which ranged between 49-84 percent of the pre-injection level [P < 0.001] The response of gastronomies muscle to sciatic nerve stimulation showed insignificant change [P > 0.05]. The intravenous administration of 15 [S]-15 methyl analogue of PGF[2] alpha a in doses of 2.5, 5.0 and 7.5 ug/kg body weight elevated the arterial blood pressure by 14-31 percent. The hypertensive effect of the drug was proportional to the dose injected. The duration of action of the methyl analogue was more long lasting than that of PGF[2] alpha. This synthetic analogue in the above mentioned doses produced significant inhibition of the knee jerk which was proportional to the dose level and ranged between 31-86 percent. The inhibitory effect of this methyl analogue in a dose of 7.5 ug/kg body weight was more prolonged than that of PGF[2] alpha a in doses of 10 or 20 ug/ kg body weight. The synthetic analogue had insignificant effect on the response of gastronomies muscle to sciatic nerve stimulation [P > 0.05]. The intravenous injection of this methyl analogue in a dose of 7.5 ug/kg body weight frequently produced initial rise in arterial blood pressure, followed by severe hypotension, apnea and loss of knee jerk