ABSTRACT
Objective To explore the mechanism of the low-frequency electrical stimulate on pedunculopontine nu-cleus to treat the Parkinson (PD) through observinge the low-frequency electrical stimulation of Pedunculopontine Nucleus (PPN) in PD rat model and the effects of neurotransmitters (GPi) neurons discharge in the medial part of the globus pallidus. Methods Thirty SD rats were randomly assigned to the control group and the PD model group, with 15 in each group. PD model was established through injecting 6-OHDA into Substantia nigra compact (SNc) of black rat. Effect of low frequency electrical stimulation, micro-electrophoresis glutamate (Glu) and its receptor blocking breaking agent MK-801,γ-aminobu-tyric acid (GABA) and its receptor antagonist bicuculline (BIC) on discharge of rat neuron GPi was examined using extracel-lular unit recording methods through seven glass microelectrode recording. Results When stimulated by low frequency electrical stimulation of PPN, reactions from the control group and neuronal response GPi in PD rats were inhibited. The aver-age discharge frequency was reduced compared to pre-stimulation (P < 0.01). Micro-electrophoresis and BIC Glu excite neurons while microiontophoresis MK-801 and GABA restrain neurons. In the background of micro-electrophoresis BIC’s excitatory effects on neuron, low-frequency electrical stimulation on PPN reduced neuronal firing frequency. And in the background of inhibition effect of micro-electrophoresis MK-801, low-frequency stimulation PPN further restrain neuronal discharge frequency. Conclusion Low frequency electrical stimulation inhibits GPi PPN neuronal activity probably though regulating neurons projecting to the Glu and GABA nerve pathways in GPi neuron.
ABSTRACT
Objective To study the effect of high frequency stimulation (HFS) in pedunculopontine nucleus (PPN) on the neuronal activities of globus pallidus internus (Gpi) in Parkinson’s disease (PD) model rats, and the mechanisms there-of. Methods Seventy male Sprague-Dawley rats were divided into two groups, control group (n=30) and PD model group (n=40). PD rat model was established by the injection of 6-OHDA into substantia nigra pars compacta (SNc) on the right side of the brain with stereotactic technique. Electrophysiological recordings were made in anaesthetized rats to investigate the ef-fects of HFS-PPN on the firing rate of the GPi neurons. Brain microdialysis combined with high-performance liquid chroma-tography was applied to detect glutamate (Glu) andγ-aminobutyric acid (GABA) levels in GPi. Results HFS-PPN caused an excitatory reaction of the majority of neurons recorded in the GPi in PD model group and control group. The mean firing rate of GPi excited neurons was significantly increased (P﹤0.01). The levels of Glu were reduced under HFS-PPN and the levels of GABA were not affected (P>0.05).Conclusion HFS-PPN heightened the electrical activity of GPi neurons and re-duced the level of Glu. These excitatory effects were probably realized by PPN-GPi direct path or other indirect path.
ABSTRACT
AIM: To study the effects of astragalosides (AS) on the proliferation and cell cycle of rat glomerular mesangial cell (MC), and verify the correlation between the influence and the AS concentration. METHODS: The experiment was carried out in the Physiological Laboratory of Liaoning Medical University from December 2006 to July 2007. Rat glomerular MCs were cultured in high glucose for 4-7 passages. The experiments were randomly divided into control group and three AS groups with different concentrations (50, 100, 200 mg/L), which were treated with high-glucose liquid and AS respectively. MC proliferation was determined with MTT colorimetric method in each group at hours 48 after intervention. MC cell cycle was detected with flow cytometry. RESULTS: ①MTT results showed that, the values of A490 nm in AS groups were lower than that in the control group at hours 48 (P