[Prolonged effect of 5-hydroxytryptophan on trace processes of neuronal activity]

In experiments on rabbits a study was made of the influence of serotonin's precursor, 5-oxytriptophane (5-OTP), on trace processes in spike activity of neurones in the visual and sensorimotor cortical areas. Rhythmic light was used as a stimulus with a frequency of 2 or 5 per second. Administration of 5-OTP produced prolonged action of the trace processes, significant for 2 per second frequency and less pronounced for 5 per second frequency of the flashes. This property was possessed both by the neurones which increased their activity frequency and those which reduced it. It is assumed that the prolonging effect of 5-OTP is the consequence of its modulating influence on the brain activity, which is manifested in a selective potentiation of the functioning of a neuronal system with a relatively lower frequency of spontaneous firing.