Effects of a lesion in the dorsal raphe nuclei performed during the juvenile period of the female rat, on puberty.
The present study examined the effect of thermic lesions on the dorsal raphe nuclei (DRN) of the female rat, performed at various ages during the prepubertal period (21, 24, or 27 days), on puberty, and at first ovulation. In comparison with sham-operated animals, the age of vaginal opening and first vaginal oestrus was delayed in rats with a DRN lesion performed at the end of the infantile period (day 21) (45.6+/-0.94 vs. 89.9+/-1.03, p < 0.05), whereas differences were not observed in animals with lesions performed during the juvenile period (day 24 or 27). The number of ova shed by ovulating animals was greater in those rats with lesions performed on day 24 or 27 (9.7+/-0.4 vs. 7.4+/-0.4; 9.5+/-0.5 vs. 7.7+/-0.4, p < 0.05). Ovarian follicular atresia in these animals was significantly lower than in control and sham-operated ones. On the day of first vaginal oestrus and 48 h after the lesion, the serotonin-hypothalamic concentration decreased in all lesioned animals. Present results support the idea of the participation of the serotoninergic system, arising from the DRN, in the neuroendocrine mechanisms regulating the onset of puberty and the first ovulation, with variations depending on animal maturity.
Ayala
M E
ME
Biology of Reproduction Research Unit, Laboratory of Puberty, Facultad de Estudios Superiores Zaragoza, México DF, México. casala@puma2.zaragoza.unam.mx
Monroy
J
J
Morales
L
L
Castro
M E
ME
Domínguez
R
R
D000375:Aging / Q000378:metabolism / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D004971:Estrus / Q000502:physiology; D005260:Female; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D009994:Osmolar Concentration; D006080:Ovarian Follicle / Q000033:anatomy & histology; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000378:metabolism
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid