CSF tryptophan and transmitter amine turnover may predict social behaviour in the normal rat

Central 5-hydroxytryptamine (5-HT) and dopamine (DA) turnovers and tryptophan concentrations were estimated in individual male rats using repeated CSF withdrawal. On subsequent pairing, the major biters of each pair (neck + body bites) were predicted by their higher concentrations of the 5-HT precursor tryptophan but not by 5-HT turnover. However, bites/pair correlated highly significantly with the lower 5-HT and DA turnover values in each pair. The investigation illustrates a new and flexible approach to the neurochemistry of social behaviour.