The ouabain-sensitive component of synaptosomal respiration.

The relationship of oxygen consumption with the activity of the synaptic Na-K-pump was investigated in rat cortical synaptosomes. Changes in oxygen consumption were monitored during the restitution of physiological ionic equilibrium in incubated synaptosomes and under the effects of ouabain and protoveratrine. The ouabain-sensitive component of synaptosomal respiration was measured and correlated with earlier data on synaptosomal K+-uptake. This ouabain-sensitive component was shown to reflect the activity of the Na-K-pump. Our results thus provide a means for the continuous monitoring of ion-pump activity in intact synaptosomes.