EFFECTS OF LONG-LASTING VOLUNTARY RUNNING ON THE CEREBRAL LEVELS OF DOPAMINE, SEROTONIN AND THEIR METABOLITES IN THE SPONTANEOUSLY HYPERTENSIVE RAT

The brain regional dopamine (DA) and serotonin (5-HT) levels and turno ver were studied in the spontaneously hypertensive rat (SHR), followin g voluntary, long-lasting (7 weeks) wheel-running exercise. Groups of rats were sacrificed 1-2 h, 23-24 h or 47-48 h after termination of th e last running session, and the cerebral tissue levels of 5-HT, 5-HIAA , DA and DOPAC were determined and compared to corresponding levels ob tained in sedentary controls. In the exercised animals, there was a se lective decrease in the limbic forebrain levels of DOPAC in the immedi ate post-exercise period (1-2 h), while the DA turnover (DOPAC/DA rati o) was not altered. In addition, the 5-HT and 5-HIAA levels in the ser otoninergic nerve terminal limbic forebrain and the 5-HT turnover (5-H IAA/5-HT ratio) in the cell, body-containing brain stem areas were dec reased in the immediate post-exercise period. No significant changes i n the DA, DOPAC, 5-HT or 5-HIAA levels, nor in the DA and 5-HT turnove r, were obtained in the remainder of the brain regions analyzed, regar dless of time after termination of running. Taken together, the presen t study indicates that voluntary exercise in the SHR gives rise to dif ferentiated regional effects on brain DA and 5-HT levels and turnover, thus supporting the view that changes in central monoaminergic activi ty are involved in the functional effects of long-term exercise. Inter estingly, the psychomotor-associated limbic forebrain areas appeared p articularly susceptible.