IS ATP A CENTRAL SYNAPTIC MEDIATOR FOR CERTAIN PRIMARY AFFERENT-FIBERS FROM MAMMALIAN SKIN
IS ATP A CENTRAL SYNAPTIC MEDIATOR FOR CERTAIN PRIMARY AFFERENT-FIBERS FROM MAMMALIAN SKIN
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DOI：
10.1073/pnas.81.21.6890
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发表时间：
1984-01-01
期刊：
影响因子：
--
通讯作者：
PERL, ER
中科院分区：
文献类型：
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作者：
FYFFE, REW;PERL, ER
将三磷酸腺苷(ATP)离子渗入猫脊髓外层神经元，观察其在初级传入纤维中央终末充当突触介质的可能性。事实证明，三磷酸腺苷对一小部分脊髓神经元具有选择性兴奋作用。这些单位以非常小的电流(2-15nA)持续地被ATP离子导入所兴奋，对皮肤的温和机械刺激有反应，通常证明来自无髓初级传入纤维的兴奋性输入。大多数被ATP兴奋的单位是专门的机械感受器；少数接受来自低阈值机械感受器和伤害性感受器的兴奋性输入的神经元也对ATP有反应。选择性感受性神经元无反应。一般情况下，三磷酸腺苷兴奋的机械感受性神经元位于胶状质深层或与之相邻的背角固有核。结果表明，在接受触觉机械感受器和细径传入纤维的兴奋性投射的中枢神经元上存在一种嘌呤能兴奋性受体，这与ATP样剂可能为这组感觉器官介导中枢突触兴奋的可能性是一致的。
The possibility that ATP acts as a synaptic mediator at the central terminals of primary afferent fibers was examined by applying it iontophoretically to neurons of the outer layers of the cat spinal cord in vivo. ATP proved to be selectively excitatory for a limited subset of spinal neurons. Those units consistently excited by ATP iontophoresis with very small currents (2-15 nA) responded to gentle mechanical stimulation of the skin and usually evidenced excitatory input from unmyelinated primary afferent fibers. Most units excited by ATP were specifically mechanoreceptive; a few neurons receiving excitatory input from both low-threshold mechanoreceptors and nociceptors also responded to ATP. Selectively nocireceptive neurons were unresponsive. Generally, the mechanoreceptive neurons excited by ATP were located in the deeper substantia gelatinosa or in the immediately adjacent nucleus proprius of the dorsal horn. The results suggest the presence of a purinergic excitatory receptor on central neurons receiving excitatory projection from tactile mechanoreceptors with fine-diameter afferent fibers and are consistent with the possibility that an ATP-like agent may mediate central synaptic excitation for this set of sense organs.