Comparative study of the hypotensive effect of a group of structural derivatives of glaucine

A comparative study was made on the hypotensive effect of a group of dehydrogenated structural derivatives of the alkaloid glaucine. The compounds studied induced a slowly occurring marked decrease in the blood pressure. Applied intravenously, they did not manifest the initial brief and very pronounced phase of the hypotensive effect, typical of glaucine, and failed to change substantially the respiration and the cardiac activity of the experimental animals. The most marked hypotensive effect was demonstrated by 7-benzoyl-dehydroglaucine (DG4), which reduced the blood pressure by about 50 and 60% respectively, when applied in doses of 1 mg/kg and 2.5 mg/kg. Applied duodenally, the dehydrogenated glaucine derivatives also manifested a gradually occurring hypotensive effect, whereby DG4 again caused the most pronounced blood pressure drop. Depending on the DG4 and glaucine doses used, the pressor effects of noradrenaline (NA) and nicotine (NIC) were moderately to strongly suppressed or completely inhibited. In experiments on cat membrana nictitans glaucine also suppressed moderately (2.5 mg/kg) or markedly (5 mg/kg) the contractile effects of NIC and NA, while DG4 did not influence (1 mg/kg) or potentiated (2.5 mg/kg) these effects.