Effect of metabolic inhibition on the excitability of isolated hippocampal CA1 neurons: developmental aspects

摘要: 1. The effects of brief exposures to hypoxia on the membrane currents isolated hippocampal CA1 neurons were studied with use whole-cell variation patch-clamp technique. Neurons acutely dissociated from immature (day 2-7) and mature 21-43) rats. 2. In current-clamp mode, Na-cyanide (CN) hyperpolarized both neurons. voltage-clamp CN decreased magnitude hyperpolarizing holding current in age groups. 3. did not have a consistent effect voltage-dependent calcium potassium but inward at ages. This was dependent: by only 10%, that approximately 40%. 4. decrease depression observed during exposure N2 (PO2 = 0), indicating electroresponses result blocking oxidative respiration. 5. hypoxia-sensitive blocked tetrodotoxin (TTX) cadmium or cesium + tetraethylammonium (TEA). Therefore this identified as voltage-dependent, fast-inactivating sodium (INa). 6. block TEA currents. neurons, left-shifted steady-state inactivation curve for INa slowed deactivation kinetics INa. caused little no change activation, fast inactivation, recovery current-voltage (I-V) relationship. 7. We conclude alter intrinsic excitability least two mechanisms: 1) alterations leakage 2) Na+ conductance are maturationally dependent. propose may play an adaptive role reducing O2 demands thus possibly delaying neuronal injury.