RESUMO
We studied the effect of somatostatin on presinaptic NMDA receptors and postsinaptic GABA, NMDA, and AMPA receptors in rat brain. It was shown that somatostatin inhibits NMDA-induced (45)Ca(2+) uptake into synaptosomes isolated from rat brain cortex (IC50=2.8×10(-11) M). Somatostatin potentiates AMPA receptors and inhibits hippocampal NMDA receptors in the entire range of examined concentrations (10(-14)-10(-7) M); it also potentiates or inhibits GABA receptor currents in a concentration-dependent manner. Our results suggest that somatostatin modulates the function of ionotropic glutamate and GABA receptors and is involved in cognitive and neurodegenerative processes in the mammalian brain.
Assuntos
Encéfalo/metabolismo , Transporte de Íons/efeitos dos fármacos , Neurônios/metabolismo , Receptores de AMPA/metabolismo , Receptores de GABA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Somatostatina/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Cálcio/metabolismo , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina/metabolismo , Sinergismo Farmacológico , Ácido Caínico/farmacologia , N-Metilaspartato/farmacologia , Neurônios/efeitos dos fármacos , Técnicas de Patch-Clamp , Ratos , Transmissão Sináptica/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Ácido gama-Aminobutírico/farmacologiaRESUMO
It was demonstrated that uridine affects presynaptic NMDA and kainite receptors of rat brain cortex. Uridine considerably inhibited (45)Ca2+ uptake into synaptoneurosomes (IC50 = 7.1 x 10(-12) M) under conditions NMDA stimulation and increased it under conditions AMPA stimulation (157.8%).
Assuntos
Córtex Cerebral/efeitos dos fármacos , Receptores de Ácido Caínico/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Sinaptossomos/metabolismo , Uridina/farmacologia , Animais , Cálcio/metabolismo , Ratos , Transmissão Sináptica/efeitos dos fármacosRESUMO
We studied the effect of prostaglandins on presynaptic NMDA receptors. Prostaglandin E2 inhibited NMDA-induced (45)Ca2+ uptake by synaptosomes in low concentrations (IC50 approximately 10 microM), but potentiated it in higher concentrations. Prostaglandin D2 increased (45)Ca2+ uptake by synaptosomes during stimulation of NMDA receptors. Our results indicate that prostaglandins D2 and E2 modulate function of presynaptic NMDA receptors.
