大腦深層光刺激對紋狀體內神經傳導物質 谷氨酸和多巴胺濃度的變化趨勢

Abstract

本研究論文以過去光刺激大鼠大腦黑質緻密部的腦波實驗所得知的較佳光刺激參數[1]，對大鼠大腦的黑質緻密部以雷射二極體光源產生波長840nm的近紅外光，在1mW、5mW、10mW三種不同強度(功率)下進行大腦深層光刺激和再刺激，並以微透析儀抽取其大腦紋狀體內的腦脊髓液，分析脊髓中神經傳導物質谷氨酸和多巴胺濃度隨時間的變化趨勢。結果發現有光刺激的大鼠其腦脊髓中谷氨酸和多巴胺的濃度和未進行光刺激的大鼠比較，分別呈現出谷氨酸濃度下降和多巴胺濃度上升的趨勢，而其中又以光刺激參數功率1 mW持續照射5分鐘造成的濃度變化最為顯著，且在第一次光刺激後能維持預期的穩定濃度直到三小時後的再次光刺激。最後，在和過去有關光刺激對腦波變化的實驗結果比較後[1]，發現腦波變化和本研究實驗中的神經傳導物質濃度變化呈現一定的關連性。此研究結果的發現，讓深層腦部光刺激在未來治療谷氨酸或多巴胺濃度失調的疾病時，提供一個新的方法和進一步研究的方向。

The main purpose of this research is to discuss the glutamate and dopamine concentrations change in striatum of rat model after deep brain light stimulation on SNc with the optimal parameters which had shown a better effect on EEG change in the previous research. The light stimulation is produced by the laser diode with wavelength in near-infrared of 840 nm, applying 1mW, 5mW and 10mW three different strength (power) to the SNc including seven sham group and fourteen light stimulation groups .The light stimulating and re-stimulating are designed according to time settings. At the same time, we use a micro-dialysis instrument to extract each rat’s brain glutamate and dopamine. As a result, we found that concentrations of glutamate and dopamine were tended to decrease and increase respectively compared to sham group. The light stimulation with 1 mW light power and time duration of 300 seconds could make the most significant change of concentrations, and its effect could last for 3 hours until next light stimulation on SNc. We found the results of neurotransmitters change after deep light brain stimulation matched previous EEG experiments which were considered to be the method to seek for the optimal light stimulation parameters. In the future, we hope the deep brain light stimulation can implement on treating the disease of imbalance neurotransmitters secretion and take more research to find the mechanism of the neurotransmitters and brainwave behavior with light stimulation.