Temporal Phase Relation of Serotonergic and Dopaminergic Oscillations Alters Seasonal Reproduction and Adrenal Function in Jungle Bush Quail and Rain Quail

ABSTRACT

Present study investigates the role of temporal phase relation of serotonergic and dopaminergic oscillations in the regulation of seasonal reproduction in summer breeding Jungle bush quail, Perdicula asiatica and autumn breeding rain quail, Coturnix coturnix coromandelica. Two sets of experiments were performed in month of August, in reproductively quiescent (RQ) bush quail and reproductively active (RA) rain quail. In experiment I, both quails received the serotonin precursor, 5-HTP and the dopamine precursor, L-DOPA (5 mg/100 gm body weight/day for 13 days) at the interval of 8-hr or 12-hr. At the termination of the study (30 days post treatment), 8-hr suppressed and 12-hr increased body weight and testicular development compared to their respective controls in both the species of quail. However, in RA rain quail, testicular development in 12-hr group was similar to control. Further, in RQ bush quail, while adrenal activity of 8-hr group was more or less similar to control, 12-hr relation stimulated the activity of steroidogenic cords. On the other hand, in RA rain quail, control and 12-hr quail adrenal activity was similar while that of 8-hr showed suppression. In experiment II (quails receiving total dose of experiment I, i.e. 32.5 mg/100 gm body weight/ day for 2 days only, and sacrificed 30 days thereafter), response of the birds were similar to that of the experiment I. These findings indicate that, 8-hr and 12-hr relation of the 5-HTP and L-DOPA administration induced suppression and stimulation of the gonadal and adrenal function respectively, irrespective of the phase of the annual gonadal cycle of the two species of quail. It is concluded that specific relation of serotonergic and dopaminergic oscillation induces reproductively quiescent or active condition out of the season as a function of their time relation. These findings also suggest that, circadian organization may regulate reproductive and metabolic seasonality irrespective of the phase of the annual gonadal cycle.

Keywords:

5-Hydroxytryptophan (5-HTP), L-Dihydroxyphenylalanine (L-DOPA), testis, adrenal, Bush quail, Rain quail, seasonal reproduction.