Effect Of Hypoxia On The P2X Receptors Of The Rat Hippocampus CA1 Neurons

For hypoxia injury, hippocampus is one of the most sensitive part of the central nerve system .The present study was going to observe the sub-types expression of P2X receptors on the rat hippocampus CA1 neurons and the effect of hypoxia on the function and expression. We examined the basic electrophysiology of acut dissociated CA1 neurons of rat hippocampus by using whole-cell patch-clamp techniques. Then we observed the action of ATP, suramin, ivermectin, low pH and hypoxia on this cell. On the other hand, we observed the expression of P2X receptors by using immunohistochemical staining before and after hypoxia. The results were as follows:1.Morphology of CA1 neurons with pyramidal phase-bright soma and its dendrites or axons were readily distinguished.2. Resting membrane potential of CA1 neurons were (-54.96±5.24)mV; Most neurons had action potentials when evoked by hyperpolarizing and depolarizing step currents (-60pA～140pA, step=20pA, time=200ms), the threshold is 37.119±4.5342mV, the times of action potentials is 8.9571±2.1506ms and the range is 83.04±10.45mV(n=45).3.On most recorded neurons(38/40), ATP can evoked depolarizing inward currents by dose dependent. The currents responded 0.1μmol/L,1μmol/L,10μmol/L,100μmol/L,1000μmol/L ATP were -2.019±0.508pA, -3.114±0.682pA, -9.529±3.928pA, -17.642±5.451pA, -18.4175±6.241pA respectively. Using suramin can inhibit the depolarization currents evoked by ATP. The effect of ATP on CA1 neurons were regulated by ivermectin(100μmol/L) and low pH(pH=6.5).4.The inward currents evoked by ATP was decreased in hypoxia condition,but suramin can still inhibit the depolarizing currents.5.Immunohistochemistry showed that there were several sub-type of P2X receptors in hippocampus CA1 neurons. After long term hypoxia, the expression of these receptors was increased.As a result, there is abundant of P2X receptors expression on the hippocampus CA1...