PHASE RELATION OF NEUROTRANSMITTER AFFECTING DRUGS (5-HTP AND L-DOPA)ALTERS PHOTO-SEXUAL RESPONSE (SCOTOSENSITIVE AND SCOTOREFRACTORY) IN JAPANESE-QUAIL

To understand the effect of temporal phase relation of circadian serot onergic and dopaminergic activity on the short day (LD 6 : 18) respons e of Japanese quail, 5-hydroxytryptophan (Serotonin precursor, 5-HTP) and L-dihydroxyphenylalanine (Dopamine precursor, L-DOPA) were adminis tered daily in six different relationships (0, 4, 8, 12 16 and 20hr). After the initial period of sexual quiescence (Scotosensitivity), quai l of the control as well as all the treated groups exhibited sexual de velopment i.e. scotorefractoriness (increase in gonadal activity and c loacal gland size). Thereafter, while quail of 0 and 4hr groups remain ed reproductively stimulated other groups showed regression. Obviously 0 and 4 hr relation between the administration of two neurotransmitte r precursor drugs eliminated reoccurrence of scotosensitivity and main tained continuous breeding condition (scotorefractoriness). These find ings suggest that Japanese quail exhibits gonadal cyclicity even under constant short days and this endogenous cycle may be altered by speci fic phase relation of circadian serotonergic and dopaminergic activiti es.