THE EFFECT OF CERTAIN BARBITURATES UPON THE OXYGEN UPTAKE AND ANAEROBIC REDUCTION OF METHYLENE BLUE BY RAT LIVER AND BRAIN

¹ From the Departments of Biochemistry and Pharmacology, School of Medicine, Western Reserve University, Cleveland

A study has been made of the effect of a number of barbiturates upon the oxygen uptake of rat liver slices and upon the anaerobic reduction of methylene blue by rat brain and liver tissue. The oxygen uptake of rat liver slices without added substrates was found to be inhibited by the following barbiturates (sodium salts) listed in the order of their effectiveness: amytal, pentobarbital, neonal, ortal, phenobarbital, evipal, alurate and dial. The narcotics were studied at a concentration range from 0.001 to 0.1 per cent and it was found that the inhibition became greater as the narcotic concentration was increased. No inhibition of the oxygen uptake was experienced in the case of sodium barbital even though the concentration was increased to 0.5 per cent. During the time interval investigated, the inhibition of the oxygen uptake was found to become greater as the period of exposure of the narcotic to the tissue was prolonged.

The anaerobic reduction of methylene blue by liver tissue without added substrates was found to be markedly inhibited by the barbiturates at a concentration of 0.1 per cent (sodium barbital was only slightly effective). The anaerobic reduction of methylene blue by rat brain in the absence of added substrates was affected less than that by liver tissue.