Antihypertensive and hemodynamic effects of 3,6-dimethamido-dibenzopyriodonium citrate (I-65)

I-65 is a new compound synthesized in China in 1984. The blood pressure of conscious or anaesthetized rats fell significantly without reflex tachycardia after iv or ig of I-65. The positive correlationship was revealed between the hypotensive effect and dosage of I-65. The antihypertensive actions of I-65 were not relative to autonomic nervous system and the rejease of histamine. which were the results of direct peripheral vascular dilation and the depression of myocardial contraction. The hemodynamic effects of iv l-65 0.8 mg/kg in anaesthetized open-chest cats were noticed: MBP, LVP. TPVR. dP/dtmax, Vmax. (dp/dt)/CPIP, LVWI, TTI. HR were decreased 27+7% (p<0.01). 19土3% (p<0.01). 11+8% (p<0.01). 26+8% (p<0.01). 45+11% (p<0.01). 25+9% (p<0.01) respectively; t-dp/dtmax was increased 47+20% (p<0.01); HR, LVEDP. CVP did not change significantly. I-65 inhibited the force of myocardial contraction much stronger than HR in the isolated perfused guinea pig hearts.