ABSTRACT
Specific temporal phase relation of neural oscillations appears to be the regulator of gonadal development in many seasonally breeding species. To find out the specific phase angle of two neural oscillations that triggers gonado-inhibitory or gonado-stimulatory response, and to test the internal coincidence model, sexually immature male Japanese quail were administered with the serotonin precursor, 5-hydroxytryptophan and the dopamine precursor, L-dihydroxyphenylalanine at hourly intervals of 6, 7, 8, 9, 10, 11 and 12 h (5 mg/100 g body weight/day for 12 days under continuous condition of light, LL). Thereafter all the groups were shifted to long photoperiod (LD16:8). During post-treatment period, in general, a significant suppression of gonadal activity was seen in the 7 h and 8 h quail and an increase in the 11 h and 12 h quail compared to the control and these effects were maintained until 105 days post treatment when the study was terminated. These findings suggest that, in addition to the effects of photoperiod, the gonadal development of Japanese quail may be also modulated by internal coincidence of serotonergic and dopaminergic oscillations (induced by the administration of their precursor drugs) and the gonadal response varies depending on the time interval between the administrations of two drugs on a circadian basis. These results also demonstrate inversion of gonadal response from 7/8 h (suppressive) to 11/12 h (stimulatory) phase relation of the two oscillations and suggest that similar to photoperiodic time measurement, Japanese quail may also detect changes in the phase angle of circadian oscillations to modulate its gonadal activity.
ABSTRACT
El presente artículo tiene como objetivo describir y analizar las ventajas de la medición de la glándula cloacal de la codorniz japonesa macho como estrategia de evaluación indirecta de la producción de hormonas relacionadas con la conducta sexual de esta especie de ave. Primero, se hace una introducción al uso de aves como modelos experimentales en endocrinología conductual; luego, se presentan los argumentos a favor del uso de medidas indirectas de la producción hormonal. Se presenta investigación que muestra la relación de la medida del área y el volumen de la glándula cloacal, con otras medidas de producción de andrógenos y se presentan algunas investigaciones representativas que han hecho uso efectivo de esta medida.
In the present article we describe and analyze the advantages of measuringthe cloacal gland of male Japanese quail as a strategy to indirectly evaluate the production of hormones related to sexual behavior in this bird species.The use of animal models in general, and birds in particular, for the studyof the relationship between hormones and behavior is first introduced.Arguments for the advantage of using indirect measures of hormone productionare presented. Research that shows the correlation between area and volume of cloacal gland with other measures of androgen production is described, and some relevant research that has made use of indirect measures is presented.