Dopaminergic agonists and their influence on the oxygenation and function activity of underperfused brain tissue

The effect of two dopaminergic agonists (apomorphine and bromocriptine) on electrical activity and oxygen supply of the brain was investigated in cats submitted to hypovolemic oligemia (mean arterial blood pressure: 45 mmHg). While both drugs stimulated the brain by prolonging the oligemia-induced seizures in the caudate nucleus and in the cerebral cortex, only apomorphine improved the pO2 distribution in the cortical tissue after 120 min oligemia. Bromocriptine, in contrast, had a beneficial effect of shorter duration. These data show that under conditions of incomplete ischemia the brain can still be activated. Furthermore, these results provide additional support for the biochemically founded hypothesis of different dopamine receptors in the brain.