RESUMO
The role played by the serotoninergic system in the control of puberty onset and first ovulation in rats is studied in this paper by analyzing the effects of injecting the neurotoxin 5,6-dihydroxytryptamine (5,6-DHT) into the dorsal (DRN) or medial (MRN) raphe nucleus of 30-day-old female rats. Complete lesion to the DRN resulted in the blockade of ovulation and a decrease in both the number of ovarian follicles and the serum concentration of follicle stimulating hormone (FSH). This treatment was also found to be associated with an increase in serotoninergic activity in the anterior and medial hypothalami. A lesion to the central portion of the DRN resulted in a significant decrease in the concentration of progesterone in serum and in the number of ova shed by ovulating animals. The lesion to the lateral portion of the DRN did not have an apparent effect on ovulation rate, the number of ova shed, nor in hormone serum concentration. The injection of propranolol to rats with a lesion to the DRN restored ovulation in 73% of treated animals and returned serotoninergic activity in the anterior hypothalamus to levels similar to those of sham-operated animals. In turn, in the medial hypothalamus, the increase in serotoninergic activity was not modified. The results presented herein suggest that serotoninergic inputs to the anterior hypothalamus have a direct influence on gonadotropin secretion and first ovulation, while the noradrenergic innervation exerts an indirect influence.
Assuntos
5,6-Di-Hidroxitriptamina/administração & dosagem , Núcleo Mediodorsal do Tálamo/efeitos dos fármacos , Núcleos da Rafe/efeitos dos fármacos , Serotoninérgicos/administração & dosagem , 5,6-Di-Hidroxitriptamina/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Mapeamento Encefálico , Estradiol/sangue , Estro/efeitos dos fármacos , Estro/metabolismo , Feminino , Hormônio Foliculoestimulante/sangue , Ácido Hidroxi-Indolacético/metabolismo , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Hormônio Luteinizante/metabolismo , Núcleo Mediodorsal do Tálamo/fisiologia , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/metabolismo , Folículo Ovariano/fisiopatologia , Ovulação/efeitos dos fármacos , Ovulação/metabolismo , Progesterona/sangue , Propranolol/farmacologia , Núcleos da Rafe/anatomia & histologia , Núcleos da Rafe/fisiologia , Ratos , Ratos Endogâmicos , Serotoninérgicos/farmacologia , Vagina/efeitos dos fármacos , Vagina/metabolismoAssuntos
5,6-Di-Hidroxitriptamina/farmacologia , Eletroacupuntura , Núcleos da Rafe/fisiologia , 5,6-Di-Hidroxitriptamina/administração & dosagem , Animais , Eletrofisiologia , Injeções Intraventriculares , Masculino , Neurônios/fisiologia , Nociceptores/fisiologia , Ratos , Serotonina/metabolismo , Medula Espinal/fisiologiaRESUMO
The role played by central 5-hydroxytryptamine (5-HT) in acupuncture analgesia (AA) has been studied in rats with the tail-flick response as the antinociceptive test. The analgesic effect of acupuncture can be enhanced or lowered by the increment or the decrement of the 5-HT level in the CNS. Furthermore, the turnover rate of 5-HT in the CNS has been found to be greatly facilitated during the period of acupuncture. The results imply that 5-HT in the CNS may be one of the most important neurochemical agents mediating AA.
Assuntos
Terapia por Acupuntura , Analgesia , Serotonina/fisiologia , 5,6-Di-Hidroxitriptamina/administração & dosagem , 5-Hidroxitriptofano/administração & dosagem , Animais , Encéfalo/metabolismo , Limiar Diferencial , Feminino , Injeções Intraperitoneais , Injeções Intraventriculares , Morfina/farmacologia , Nociceptores/fisiologia , Ratos , Serotonina/metabolismo , Medula Espinal/metabolismo , Triptofano/administração & dosagemAssuntos
5,6-Di-Hidroxitriptamina/farmacologia , Regulação da Temperatura Corporal/efeitos dos fármacos , Triptaminas/farmacologia , 5,6-Di-Hidroxitriptamina/administração & dosagem , Animais , Comportamento Animal/efeitos dos fármacos , Temperatura Baixa , Haplorrinos , Temperatura Alta , Hipotálamo/anatomia & histologia , Macaca mulatta , Masculino , Microinjeções , Fatores de TempoRESUMO
A bilateral microinjection into the anterior hypothalamus of 5,6-dihydroxytryptamin (5,6-DHT), a substance that lesions serotonin (5-HT)-containing neurons, caused a rise in the body temperature of the rat. The anatomical sites were the same as those at which 5-HT given in the same dose range (1.25-2.5 mug) evoked a similar hyperthermia. When exposed for one hour to a temperature of either 35 degrees C or 8 degrees C, the rats were not able to defend against the heat or cold, respectively. The magnitude of this thermoregulatory deficit depended upon the dose of 5,6-DHT given as well as the site of injection. A partial recovery from the warmth deficit was evident 13-17 days following the 5,6-DHT microinjection. Food and water intakes were also suppressed significantly and body weights declined concomitantly. These results provide additional evidence to support the view that a serotonergic mechanism in the hypothalamus is involved in both thermoregulation and the control of ingestive behavior.