Interaction of specific temporal phase relations of circadian neural oscillations and long term photoperiodic responses in Japanese quail, Coturnix coturnix japonica

These results indicate that 12-h phase relation of neurotransmitter precursors not only initiates early onset of scotorefractoriness i.e., full development of gonad even under short-day length but maintains it continuously (a long lasting effect) unlike control and the 8-h relation dissipates it, making the quail scotosensitive. On the other hand, the 8-h phase relation suppresses the gonado-stimulatory effect of long days but this effect is transitory. Thus the 12-h phase relation is gonado-stimulatory under short day conditions and the 8-h relation is gonado-inhibitory even under long days, inducing scotorefractoriness and photorefractoriness, respectively, it is suggested that effects of specific temporal phase relation of circadian neural oscillations similar to photoperiodic effects, are not only mediated by HPG axis but may also modulate the classical photoperiodic responses of Japanese quail.