[Effect of cortical spreading depression on spontaneous firing activities of STN neurons in rats].

AIM: To observe the effect of cortical spreading depression (CSD) on the spontaneous firing activities of neurons of subthalamic nucleus (STN) in normal and model rat of Parkinson's disease (PD).

METHODS

Extracellular recording was used to research the neuronal electric activities in subthalamic neurons. The changes of the discharge rates of subthalamic neurons were observed in control and PD rats after intracortical microinjection of KCl solution.

RESULTS

The discharge rates of subthalamic neurons in control and PD rats were (9.78 +/- 0.71) Hz and (23.81 +/- 1.08) Hz, respectively. The discharge rate of PD rats was increased significantly when compared with those of the control rats and the percentage of neurons discharging in bursts was obviously higher than those of control rats (P < 0.01). After a long latent period secondary to intracortical injection of KCl solution, the discharge rates in both group of subthalamic neurons were decreased apparently, then recovered slowly.

CONCLUSION

The discharge rate and bursting pattern are increased in PD rats and these abnormal activities can be improved by cortical depression. This result indicates that the changes in cortical excitability may be one of the factors increasing the activity of STN in PD.