Effect of amphetamine and dopamine on oxygen uptake of rat brain slices in vitro

Effects of d-amphetamine and dopamine on rat brain cortical slices respiration were estimated to assess whether these drugs might modify membrane (Na+ + K+)-ATPase activity in intact cells as they do in isolate enzyme systems. d-Amphetamine, 10(-5) M (140%), 10(-6) M (123%) 10(-7) M (131%) and 10(-7) M (129%). These results may be related to estimates of (Na+ + K+)-ATPase activity in subcellular systems. In an incubation medium containing calcium, 10(-4) M ouabain does not modify brain slices respiration, but fully antagonizes oxygen consumption increases induced by d-amphetamine or dopamine, which might thus be mediated by membrane ATPase activity. Either phenoxybenzamine, oxprenolol or halo-peridol, nullify those metabolic effects of d-amphetamine and dopamine, by means of unspecific mechanisms rather than by a specific interaction at drug receptor sites. It is suggested that cell respiratory control is the final resultant of mechanisms which might be separately, and oppositely, modified by drugs.