A Comparation Of Electrophysiology Between Cultured Cortical Neurons And Maybolls From Rats

Objective Whole cell patch-clamp technique was empolyed in present experiments to investigate the activities of voltage-gated ion channels in the cultured cortical neurons and skeletal muscle cells(myoballs). Our aims are as following:1. To establish the whole cell patch-clamp recording technique in our laboratory. 2. To observe the essential characteristics of voltage-gated ion channels in the myoballs. 3. To find out the essential characteristics of voltage-gated ion channels in the cortical neurons. 4. To compare the characteristics of the voltage-gated ion channels in the cortical neurons with those in the myoballs.Methods Dispersed by mechnics and trypsin-digestion, the cortical neurons and myoballs out of muscle cells were obtained with primary culturing technique and used to establish the whole-cell patch clamp recording technique, and sodium, potassium and calcium currents of the voltage-gated ion channels in these two kinds of cells were recorded and analysed.Results1. The cortical neurons and myoballs, which suit the whole-cell patch clamp recording technique, were cultured.2. The characteristics of ion channels in the cortical neurons(1) Sodium currents recorded in the cultured cortical neurons as potassium currents and calcium currents were blocked. The sodium currents reached peak value quickly as soon as being activated ,and decayed quickly, and were sensitive to TTX. The average half recovery time of sodium channels of 15 cells was 3.92±0.68 ms.(2) Potassium currents compose of IA currents and IK currents. The IA currents were sensitive to 4-AP(1 mmol/L). The IK currents inactivated slowly(the current did't decay within 100 ms), and were sensitive to TEA(10 mmol/L) and rectified outwardly.(3) Calcium currents recorded in the cultured cortical neurons as sodium currents and potassium currents were blocked. The amplitude of calcium currents of the cortical neurons was low.(4) Acetylchline (2 mmol/L) could increase the firing rate and the amplitude of the sEPSC in the cultured cortical neurons.3. The characteristics of ion channels in the myoballs(1) Sodium currents recorded in the cultured myoballs reached peak value quickly as being activated, and decayed quickly and were sensitive to TTX. The average half recovery time of sodium channels of 15 cells was 15.52±1.03 ms.(2) The IK currents we recorded in the cultured myoballs did't decay within 100 ms, and were sensitive to TEA(10 mmo/L) and rectified outwardly.(3) Calcium currents recorded in the cultured myoballs as sodium currents and potassium currents were blocked.4. The comparation of the electrophysiology of the voltage-gated ion channels in the cortical neurons with that of the myoballs.(1) The sodium currents in both the myoballs and the cortical neurons activated and inactivated quickly, and were sensitive to TTX, but the sodium channels in the myoballs recovered slower than those in the cortical neurons.(2) The IK currents were recorded in both the cortical neurons and the myoballs, and activated and inactivated slowly, and were sensitive to TEA, while the IA currents were recorded only in the cortical neurons. Conclusions1. We established the culture technique of the cortical neurons and the myoballs suitable for whole cell patch-clamp technique.2. We established reliable whole cell patch-clamp technique by using cultured cortical neurons and myoballs.3. We recorded the sodium, potassium and calcium currents in the cultured cortical neurons and the myoballs, as well as the spontaneous excitatory post synaptic current (sEPSC) in the cortical neurons with the whole cell patch-clamp technique.4. The component of potassium currents of the cortical neurons differed from that of the myoballs.5. Acetylchline (2 mmol/L) could enhance the sEPSC of cultured cortical neurons.