Brain catecholamine metabolism and avoidance conditioning in rats.

Male albino rats were trained in a shuttle-box by presentation of 50 trials and were grouped according to the performance level. The disappearance of labelled catecholamine pool was studied after intraventricular injection of tritiated noradrenaline in the neocortex, brain stem, hypothalamus and hippocampus. Rats with a high performance level showed a greater disappearance rate of the labelled catecholamine pool than low or medium performers. In another experimental series the animals were grouped on the basis of their performance level which was tested 2 days before the intraventricular injection of the tracer. There was no significant difference in disappearance rates between the good and poor performances. It is assumed that integration of the goal-directed motor pattern is mediated through catecholaminergic (noradrenergic) neuronal mechanisms.