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標題: | 貓延腦巨細胞網核抑心機轉之電生理研究 Electrophysiological Study on the Cardioinhibitory Mechanism of the Gigantocellular Reticular Nucleus in the Cat. |
作者: | 蘇俊魁 |
出版年 : | 1986 |
學位: | 碩士 |
摘要: | 以氯醛醣及?酯麻醉的貓為材料,以三種方法探討巨細胞網核抑心作用的可能機制。第一;以麩胺酸刺激法,確認在巨細胞網核中有抑心神經元的存在。第二;用細胞外單—神經元記錄的方法,記錄了78個巨細胞網核的神經元。45%(27/60)的神經元放電率會隨著由靜脈注射norepinephrine和nitroglycerin所引起的血壓升降而改變。20%(15/60)的神經元之放電型式與心臟節律相關。有18%(11/61)的巨細胞網核,能夠被刺激同側或對側的背核/弧核而引發其逆行性動作電位。第三;電刺激同側的巨細胞網核或背核/孤核,於同側迷走神經幹分別記錄到六個或四個誘發電位,兩者之第三及第四波潛伏期時間吻合,傳導速度屬於B—纖維。這些結果顯示存在於巨細胞網核中之抑心神經元,一部分接受感壓接受器傳入訊號,其產生之神經衝動經由其投射至背核/弧核之軸突傳遞,最後經由迷走神經B-纖維傳出而達成抑心作用。 Three series of experiments were undertaken to further illucidate the cardioinhibitory mechanisms of the gigantocellular reticular nucleus (GRN) in chloralose-urethane anesthetized cats. Firstly, cardioinhibitory neurons present in the GRN was confirmed with glutamate microstimulation. Secondly, 78 GRN neurons were recorded with extracellular single-unit recording technique. Discharge rates of 45% (27/60) of these neurons correlated with fluctuation of mean arterial pressure induced by intravenous norepinephrine and nitroglycerin. Activities of 25% (15/60) of these neurons were time-locked with the pressure pulses (cardiac rhythm-rel related). And 18% (11/61) of the neurons could be antidromically activated from the region of the dorsal motor nucleus and the nucleus tractus solitarius (DMN/NTS). Thirdly, compound action potantial was recorded.from the desheathed cervical vagus nerve. Electrical stimulation of the ipsilateral GRN or the ipsilateral DMN/NTS evoked 6 and 4 negative waves in the vagus, respectively. The latencies of the third and the fourth waves evoked from the GRN matched with corresponding third and fourth waves from the DMN/NTS, judging with antidromic latency between these two locations obatined from the single unit experiment. Also, the conduction velocities of these two waves were within the range of the vagal B-fibers. These findings suggest that some of the cardioinhibitory neurons in the GRN receive inputs from the baroreceptors, their impulses can influence the heart by way of monosynaptic connections to the DMN/NTS and finally the B-fiber of the vagus. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75582 |
全文授權: | 未授權 |
顯示於系所單位: | 動物學研究所 |
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