NEURONS IN COMMISSURAL NUCLEUS-TRACTUS-SOLITARII REQUIRED FOR FULL EXPRESSION OF THE PULMONARY C-FIBER REFLEX IN RAT
NEURONS IN COMMISSURAL NUCLEUS-TRACTUS-SOLITARII REQUIRED FOR FULL EXPRESSION OF THE PULMONARY C-FIBER REFLEX IN RAT
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DOI：
10.1113/jphysiol.1991.sp018740
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发表时间：
1991-09-01
影响因子：
5.5
通讯作者：
JOAD, JP
中科院分区：
文献类型：
--
作者：
BONHAM, AC;JOAD, JP
1. 肺C纤维反射由激活肺中的肺C纤维末梢触发，包括快速浅呼吸（其之前可能有呼吸暂停）、心动过缓和低血压。 这项工作的目的是确定近端突触在这种反射。 从飞行员的数据，我们假设，在一个离散的区域中的连合核孤束核（NTS）的神经元所需的肺C纤维反射的充分表达。 在麻醉、单侧迷走神经切断、自主呼吸的大鼠中进行研究，测量膈肌肌电图、动脉压和血气。 右心房注射苯二胍（PDG）诱发肺C纤维反射。 通过多管移液器进行单侧NTS注射，其中含有DL-高半胱氨酸（DLH）来模拟反射，含有氯化钴来可逆地损害反射，和/或含有染料来标记注射部位。2. 26只大鼠右心房注射PDG（5-16 μ g·kg ~（-1））产生经典的肺C纤维反射：迷走神经介导的快速浅呼吸、心动过缓和震颤的快速发作. 在30只大鼠的NTS连合核的背内侧注射DLH（3-12 nl，20 mM，总计60-240 pmol），模仿肺C纤维反射，产生快速浅呼吸、低血压和轻微心动过缓。 通过在DLH产生快速浅呼吸的部位注射氯化钴（15-30 nl，100 mM）中断神经元传递，可逆地损害了15只大鼠右心房注射PDG产生的快速浅呼吸和心动过缓。 DLH产生快速浅呼吸和钴损害肺C纤维反射的连合区在NTS内从尾侧720-1100 μ m延伸到奥贝，从中线侧30-200 μ m延伸到脑干背侧表面腹侧200-600 μ m。 两者合计，结果表明，在一个离散的区域内的背内侧连合核在尾侧NTS的神经元需要充分表达肺C纤维反射。
1. The pulmonary C fibre reflex, triggered by activating pulmonary C fibre endings in the lung, consists of rapid shallow breathing (which may be preceded by apnoea), bradycardia, and hypotension. The purpose of this work was to identify proximal synapses in this reflex. From pilot data, we hypothesized that neurones in a discrete region of the commissural nucleus in the nucleus tractus solitarii (NTS) are required for full expression of the pulmonary C fibre reflex. Studies were carried out in urethane-anaesthetized, unilaterally vagotomized, spontaneously breathing rats, in which diaphragm electromyogram, arterial pressure, and blood gases were measured. Phenyldiguanide (PDG) was injected in the right atrium to elicit the pulmonary C fibre reflex. Unilateral NTS injections were made through multibarrelled pipettes containing DL-homocysteic acid (DLH) to mimic the reflex, cobalt chloride to reversibly impair the reflex, and/or dye to mark the injection sites.2. PDG (5-16-mu-g kg-1) injected in the right atrium of twenty-six rats produced the classic pulmonary C fibre reflex: a vagally mediated, rapid onset of rapid shallow breathing, bradycardia and hypotension.3. Injection of DLH (3-12 nl of 20 mM for a total of 60-240 pmol) in the dorsomedial aspect of the commissural nucleus of the NTS in thirty rats mimicked the pulmonary C fibre reflex, producing rapid shallow breathing, hypotension, and a slight bradycardia.4. Interruption of neuronal transmission by injecting cobalt chloride (15-30 nl of 100 mM) in the site where DLH produced rapid shallow breathing, reversibly impaired the rapid shallow breathing and bradycardia produced by right atrial injections of PDG in fifteen rats. The commissural region where DLH produced rapid shallow breathing and cobalt impaired the pulmonary C fibre reflex extended from 720-1100-mu-m caudal to the obex, 30-200-mu-m lateral to mid-line, and 200-600-mu-m ventral to the dorsal surface of the brain stem within the NTS.5. Taken together, the results suggest that neurones within a discrete region in the dorsomedial commissural nucleus in caudal NTS are required for full expression of the pulmonary C fibre reflex.