[New data on serotoninergic mechanisms in ovulation in the cyclic female rat]

Injection of parachlorophenylalanine on dioestrus II at 18:00 was shown to decrease ovulation frequency in 4-day cyclic female rats. This effect was overcome by either HTP, or oestradiol benzoate, when administered on dioestrus II, at 18:00 and 10:00 - 11:00 respectively. No antiovulatory action of PCPA was observed on prooestrus at 13:00. These results provide support to the specificity of action of serotonin in the control of ovulation in the cyclic rat. They also suggest an interaction of serotonin and oestrogens in this control.