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J Monroy1 , ME Castro1 , ME Ayala1 *, R Domínguez1 *
Biology of Reproduction Research Unit, FES Zaragoza UNAM, México D.F., México 1
The serotonin inervation of the hypothalamus derives from neurons located in the dorsal and medial raphe nuclei. In the adult rat these nuclei play different roles in that regulation of secretion of GnRH and gonadotropins. Also there is evidence that the participation of serotonin in the regulation of gonadotropin secretion is different in adult and pre-pubertal animals. Based on these observations we decided to analyze the effects of the injection of 10 mg of 5,6-DHT or ascorbic acid into the DRN or MRN of 30-day-old rats on first ovulation. A nontreated control group was also included. The animals were sacrificed on the day of first vaginal estrus. Ascorbic acid injection into the DRN or MRN did not affect ovulation (16/18 and 10/14 ovulated vs. 37/47) nor the number of ova shed (8.9±0.7, 9.3±.7 vs. 8.9±.4) The injection of 5,6-DHT into the DRN resulted in the partial blockade of ovulation (11/26 did not ovulate vs. 2/18 injected with ascorbic acid, p<0.05). The number of ova shed by ovulating animals was lower (6.4±0.6 vs. 8.9±0.7, p<0.05). When the injection of the 5,6-DHT was realized into the MRN, the ovulation rate and the number of ova shed were similar to those injected with ascorbic acid. This result suggests that the serotoninergic innervation arising in the DRN is essential for the ovulation occurring at puberty, while it seems that the MRN did not participate. Supported by DGAPA IN-2088796, PAEP and PUIS.
This abstract is being presented on Tuesday, August 3 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.