貓延腦黑暗縫合核呼吸神經元之特性
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Date
1996-12-??
Authors
吳英賓
黃基礎
王雪娥
Journal Title
Journal ISSN
Volume Title
Publisher
國立臺灣師範大學生命科學學系
Department of Life Science, NTNU
Department of Life Science, NTNU
Abstract
本研究是想探討延腦黑暗縫合核(nucleus raphe obscurus ; NRO)是否含有呼吸有關神經元，並觀察其對二氧化碳濃度增加及電刺激迷走神經傳入纖維的反應。貓經去大腦、麻痺、切斷兩側迷走神經後，以人工呼吸器維持通氣，呼吸末氣體濃度維持在高氧及二氧化碳濃度正常。分離並記錄膈神經活動。以金屬微電極記錄NRO神經元放電，然後提高二氧化碳濃度或電刺激迷走神經傳入纖維，以測試神經元的反應。在所記錄的133個神經元中，與呼吸有關的神經元有66個，約佔半數，可分為呼氣神經元(E)、吸氣呼氣神經元(IE)、呼氣吸氣神經元(EI)及連續性呼氣吸氣神經元(T-EI)、連續性吸氣呼氣神經元(T-IE)等，其中以EI及T-EI所佔比例較高，其次是IE與T- IE。在66個呼吸神經元中，有40個測試對二氧化碳濃度升高的反應，結果有18個神經元放電率降低(p<0.05)，8個放電率升高，其餘反應不規則。有13個與呼吸有關神經元測試對迷走神經傳入纖維興奮的反應，有9個神經元放電率降低(p<0.05)，3個升高，1個不受影響。這些結果顯示，延腦黑暗縫合核的呼吸神經元會受到化學接受器與肺伸張接受器之調節，暗示這些呼吸神經元對呼吸管制可能扮演重要角色。
The purpose of the present study was to characterize respiratory-related neurons within the nucleus raphe obscurus (NRO) and to examine their responses to hypercapnia and vagal afferent stimulation. Cat was decerebrated, paralyzed, vagotomized and ventilated. End-tidal fractional concentration of CO2 was maintained at hyperoxic normocapnia. The phrenic nerve was isolated and its activity was monitored. Neuron activity within the NRO was recorded and evaluated to the response to hypercapnia or vagal afferent excitation. Sixty-six of 133 neurons recorded showed respiratory-related activities. They were classified as expiratory-inspiratory (EI), inspiratory-expiratory (IE), tonic inspiratory-expiratory (T-IE) and tonic expiratory-inspiratory (T-EI) or expiratory (E) patterns according to their time-related with phrenic discharge. Responses of 40 respiratory-related neurons to hypercapnia were examined. Discharge rate of 18 neurons was significantly reduced in response to hypercapnia while 8 neurons was enhanced. The remaindering neurons displayed irregular pattern as the concentration of carbon dioxide was increased. With vagal stimulation, most of the neurons (9 of 13) showed a reduction of discharge rate (p<0.05) whereas the others were either increased or unaffected. These results indicate that respiratory-related neurons within the NRO can be modulated by the inputs from the chemoreceptors and vagal afferents. It also suggest that the NRO may play a role in the regulation of respiration.
The purpose of the present study was to characterize respiratory-related neurons within the nucleus raphe obscurus (NRO) and to examine their responses to hypercapnia and vagal afferent stimulation. Cat was decerebrated, paralyzed, vagotomized and ventilated. End-tidal fractional concentration of CO2 was maintained at hyperoxic normocapnia. The phrenic nerve was isolated and its activity was monitored. Neuron activity within the NRO was recorded and evaluated to the response to hypercapnia or vagal afferent excitation. Sixty-six of 133 neurons recorded showed respiratory-related activities. They were classified as expiratory-inspiratory (EI), inspiratory-expiratory (IE), tonic inspiratory-expiratory (T-IE) and tonic expiratory-inspiratory (T-EI) or expiratory (E) patterns according to their time-related with phrenic discharge. Responses of 40 respiratory-related neurons to hypercapnia were examined. Discharge rate of 18 neurons was significantly reduced in response to hypercapnia while 8 neurons was enhanced. The remaindering neurons displayed irregular pattern as the concentration of carbon dioxide was increased. With vagal stimulation, most of the neurons (9 of 13) showed a reduction of discharge rate (p<0.05) whereas the others were either increased or unaffected. These results indicate that respiratory-related neurons within the NRO can be modulated by the inputs from the chemoreceptors and vagal afferents. It also suggest that the NRO may play a role in the regulation of respiration.