RESUMO
The effects of peptide ACTH4-7-PGP (Semax) were studied in 12 min after its intraperitoneal (in doses of 5, 15, 50, 150, and 450 µg/kg) or intracerebroventricular (in doses of 16, 40, and 400 pg) administration to rats with different types of pain and pain-induced behavior. It was found that the peptide increased pain sensitivity and induced avoidance behavior during thermal stimulation ("hot plate" test), but had an analgesic effect (more pronounced after central administration) and weakened emotional-affective behavior in electrocutaneous stimulation of the paws (foot-shock model) and tail in rats. It was shown that changes in activity of supraspinal brain structures were of primary importance in the mechanism of action on the nociceptive process and the formation of behavior.
Assuntos
Hormônio Adrenocorticotrópico/análogos & derivados , Limiar da Dor/efeitos dos fármacos , Dor/fisiopatologia , Fragmentos de Peptídeos/administração & dosagem , Hormônio Adrenocorticotrópico/administração & dosagem , Analgésicos , Animais , Comportamento Animal , Encéfalo/efeitos dos fármacos , Estimulação Elétrica , Hipotálamo/efeitos dos fármacos , Infusões Intraventriculares , Injeções Intraperitoneais , Masculino , Nociceptividade/efeitos dos fármacos , Dor/tratamento farmacológico , Manejo da Dor , Medição da Dor , Peptídeos/farmacologia , Permeabilidade , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Intraperitoneal treatment with an analogue of gonadotropin-releasing hormone in doses of 0.004-450 microg/kg produced an analgesic effect on male mice in the hot plate test. Castration significantly elevated the nociceptive thresholds. In castrated mice the effects of the test peptide were less pronounced and had an algesic nature. Our results indicate that these effects depend on functional activity of the hypothalamic-pituitary-gonadal axis.