LOWERING OF ARTERIAL BLOOD PRESSURE IN RATS BY INTRATHECAL INJECTION OF MU AGONIST PL017 AND KAPPA AGONIST 66A-078
Mei Lin;Han Jisheng Department of Physiology
Intrathecal (ITH) injection of PL017, a potent and specific agonist for mu receptor, and 66A-078,a metabolically stable analogue of dynorphin-A, resulted in a dramatic decrease in mean arterialpressure (MAP) of nembutal anaesthetized male rats. PL017 at doses of 2.5-10 μg, 66A-078 at doses of 0.25-4 μg produced a dose-dependent decreaseof MAP, the depressor effect of PL017 and 66A-078 were prevented or reversed by their specificantagonists β-FNA and nor-BNI, respectively. Intravenous injection of the centrally effective doseproduced no significant depressor effect. It is concluded that mu and kappa opioid receptors in thespinal cord of rat seem to mediate a suppressive effect on cardiovascular activities.