RESUMEN
OXYS rats with hereditary hyperproduction of active oxidative radicals and early disorders in the mitochondrial structure and functions are an interesting model for studies of age-specific features of synaptic plasticity. The formation of long-term posttetanic potentiation in the mossy fibers-CA3 pyramidal neuron system were studied in hippocampal slices from Wistar and OXYS rats aged 3 and 4.5 months (young), 11 (middle-aged), and 18 months (old). No appreciable age-related differences were detected in the amplitudes and latencies of stimulatory postsynaptic summary potentials of the mossy synapses evoked by test stimuli in Wistar and OXYS rat groups of different age and between the two strains. The capacity to induction and formation of long-term posttetanic potentiation and its value decreased in 18-month-old Wistar rats, which attested to disorders in synaptic plasticity of old animals. The capacity to induction and formation of long-term posttetanic potentiation and its value in OXYS were lower than Wistar rats of the same age in all the studied groups.
Asunto(s)
Envejecimiento/fisiología , Región CA3 Hipocampal/fisiología , Potenciales Postsinápticos Excitadores/fisiología , Potenciación a Largo Plazo/fisiología , Fibras Musgosas del Hipocampo/fisiología , Animales , Estimulación Eléctrica , Humanos , Masculino , Microtomía , Células Piramidales/citología , Células Piramidales/fisiología , Ratas , Ratas Wistar , Sinapsis/fisiología , Transmisión Sináptica/fisiologíaRESUMEN
Parameters of long-term potentiation in the system mossy fibers-CA3 pyramidal neurons in hippocampal slices in experimental animals vary during the formation of chronic opiate dependence. During the first day of morphine treatment, the value of potentiation was significantly lower than in controls. Starting from day 8 and at early stages of dependence (days 25-29), facilitation of long-term potentiation was recorded. Incubation of the slices with L-type Ca(2+)-channel blocker nifedipine did not change the response to the test stimuli and did not affect potentiation induction in hippocampal slices from control and morphine-treated animals. Nifedipine had no effect on long-term potentiation of mossy fibers in the control and at early terms of morphine treatment, but significantly reduced its facilitation at later terms.