ABSTRACT
AIM: The effects of low-glucose on long-term potentiation (LTP) in the CA1 region of hippocapal slices of immature (15-16 days old) and adult (56-63 days old) rats were examined. METHODS: The technique of electrophysiology was used, and the slopes of the field excitatory postsynaptic potentials (S-EPSP) were measured. RESULTS: When slices were exposed to glucose medium at concentrations of 3 or 1.5 mmol/L, S-EPSP decreased significantly. In the slices from adult rats, only short-term potentiation was elicited by high frequency stimulation in the medium of 3 or 1.5 mmol/L glucose. However, in the slices from immature rats, LTP was still induced in the medium of 3 mmol/L glucose. CONCLUSION: Low-glucose medium depressed the synaptic transmission. In terms of the synaptic plasticity, the low-glucose endurance in immature rats was stronger than that in adult rats.
ABSTRACT
AIM: To examine whether reactive oxygen species (ROS) is involved in the neuroprotection by mitochondrial ATP- sensitive potassium channel (mitoKATp) in rat hippocampal slices during hypoxia. METHODS: The technique of elec-trophysiology was used, and the latency to hypoxic depolarization (HD) and the amplitude of population spike (PS) in the stratum pyramidale of the CA1 region were measured. RESULTS: Pretreatment of the slices with diazoxide (DIA, a mitoKATP opener, at concentration of 300 ?mol/L) , prolonged the latency to HD, delayed the onset of PS disappearance and improved the recovery of PS after reoxygenation. The effects induced by DIA were attenuated by 5 - hydroxydecanoic acid (a mitoKATP blocker, at concentration of 200 ?mol/L). Pretreatment with N - 2 - mercaptopropionyl glycine (MPG, a ROS scavenger, at concentration of 500 ?mol/L), also abrogated the effects induced by DIA, while treatment of MPG alone had no effect on PS and HD. CONCLUSION: ROS participates in neuroprotection offered by mitoKATp opener during hypoxia.