Pharmacological studies on 3-[gamma-(p-fluorobenzoyl)propyl]-2,3,4,4a,5,6-hexahydro-1 (H)-pyrazino(1,2-a) quinoline hydrochloride (compound 69/183). Part II: Effect on cardiac dynamics.

Effect of 3-[gamma-(p-fluorobenzoyl)propyl]-2,3,4,4a,5,6-hexahydro-1-(H)-pyrazino(1,2-a)quinoline hydrochloride (centpyraquin, 69/183) on the cardiac function has been studied in situ in cat and dog and on isolated guinea pig heart. Centpyraquin (1.0 mg/kg i.v.) decreased cardiac output (20%) and total peripheral resistance (18%) along with blood pressure (40%). The decrease in dp/dt and PTI were secondary to hypotension. The contractility of the auricle as well as the ventricle was not decreased. In the heart-lung preparation of dog, centpyraquin (5 mg) had an inhibitory effect on the heart. The contractility of the isolated guinea pig heart was not changed up to 200 micrograms dose but higher doses had negative inotropic effect. The compound had no significant effect on ECG of cat. The effect of norepinephrine on dp/dt and PTI was potentiated. Isoproterenol induced hypotension was not changed but the cardiac effects were potentiated.