Pharmacological studies on Natulan (Procarbazine Hydrochlodide)

Effects of Natulan, which had been proposed to be antitumor and monoamine oxidase inhibiting agents, on the cardiovascular system and intestinal movements were studied using rabbits, dogs, cats and guinea-pigs. When Natulan was administered intravenously, it caused slight excitation of respiration, depressor effect on blood pressure and no effect on cardiac movements in rabbits, and hypotension in cats, while it brought about weak hypertension and positive chronotropic effect in dogs. Natulan inhibited movements of isolated guinea-pig heart and rabbit atria. Pressor and positive chronotropic effects in dogs were eliminated by antiadrenergic agents, and these effects were diminished by repeated administration. Prior administration of reserpine exhibited that sympathomimetic effects of Natulan were potentiated in dogs, while depressor response was reversed to pressor response in cats. Natulan inhibited the blood pressure responses to carotid occlusion and vagus stimulation, and tended to inhibited the responses to splanchnic stimulation and dimethylphenylpiperadinium. Natulan inhibited movements of isolated intestine and induced slight inhibition followed by weak excitation in situ. These pharmacological responses to Natulan were observed when it was administered in large doses.