RESUMO
Consistent with a serotonergic-midbrain raphe model of tonic immobility, four experiments designed to affect changes in serum tryptophan produced reliable effects on the duration of the response in chickens. Systemic injections of tryptophan, the dietary precursor to serotonin, led to a dose-dependent increase in immobility, with optimal effects being observed within 30 min after injection. Dietary depletion of endogenous tryptophan served to attenuate the duration of immobility, and a diet completely free of tryptophan, but supplemented with niacin, practically abolished the reaction. Dietary replacement served to reinstate the response. In a fifth experiment, tryptamine, an alternative metabolic by-product of tryptophan, was found to have no effect on immobility. The data are discussed in light of evidence showing serotonergic involvement in tonic immobility.
Assuntos
Galinhas , Dieta , Movimento/efeitos dos fármacos , Triptofano/farmacologia , Administração Oral , Animais , Relação Dose-Resposta a Droga , Injeções Intraperitoneais , Ácidos Nicotínicos/farmacologia , Restrição Física , Serotonina/biossíntese , Fatores de Tempo , Triptaminas/farmacologia , Triptofano/administração & dosagem , Triptofano/sangueRESUMO
Chickens were given varying dosages of delta 3-, delta 8-, and delta 9-THC and tested for duration of tonic immobility (TI). Although all derivatives had a profound facilitation effect, delta 9-THC was the most potent. These results are unusual in that TI is a well documented fear-potentiated reaction and THC generally has tranquilization-like effects.
Assuntos
Cannabis/análogos & derivados , Dronabinol/análogos & derivados , Movimento/efeitos dos fármacos , Animais , Galinhas , Depressão Química , Dronabinol/farmacologia , Relação Estrutura-AtividadeRESUMO
Small doses of morphine, within the range of 0.02 mg/kg to 10.15 mg/kg were administered to chickens (Gallus gallus) and the effect on the fear-based tonic immobility (TI) response determined. All doses at and above 0.13 mg/kg enhanced the TI response significantly above the levels produced for the 0.2 mg/kg dose and the distilled water control group. Administration of a single large dose of p-chlorophenylalanine prevented the morphine-induced enhancement of TI. It was suggested that serotonin systems mediate morphine effects on tonic immobility in chickens.
