Abstract: Objective   To study the effect of high frequency stimulation (HFS) of pedunculopontine nucleus (PPN) on the neuronal activities of globus pallidus internus (Gpi) in Parkinson’s disease (PD) model rats and measure the level of amino acids neurotransmitter. Methods   Seventy male Sprague-Dawley rats were divided into two groups, control group(n=30) and PD model group(n=40). PD model rats were established by the injection of 6-OHDA into SNc with stereotactic technique on the right side of the brain. Electrophysiological recordings were made in anaesthetized rats to investigate the effects of HFS-PPN on the firing rate of the GPi neurons. Brain microdialysis combined with high-performance liquid chromatography was applied to detect glutamate (Glu) andγ-aminobutyric acid (GABA) levels in the GPi. Results   HFS-PPN caused an excitatory reaction of the majority of neurons recorded in the GPi in the PD rats and control group rats, the mean firing rate of GPi excited neurons was significantly increased; The levels of Glu were reduced under HFS-PPN and the levels of GABA were not affected. Conclusion    HFS-PPN heightened the electrical activity of GPi neurons and reduced the level of Glu. This excitatory effects were probably realized by PPN-GPi direct path or other indirect path.

Key words: Parkinson disease, Disease Models, Animal, oxidopamine, Electrical stimulation, globus pallidus, glutamic acid, γ氨基丁酸