Cumberbatch M J, Herrero J F, Headley P M
Department of Physiology, School of Medical Sciences, University of Bristol, UK.
Neurosci Lett. 1994 Nov 7;181(1-2):98-102. doi: 10.1016/0304-3940(94)90569-x.
The ability of excitatory amino acids (EAAs) to modulate nociceptive and non-nociceptive responses was tested on spinal neurones of the anaesthetized rat. NMDA (N-methyl-D-aspartate), AMPA ((RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate) and kainate were applied by iontophoretic ejection to increase the background firing rate of each cell to approximately 25 spikes/s. Responses to noxious heat and pinch and innocuous tap stimuli were enhanced to similar degrees by all three EAAs and returned to control immediately following termination of EAA ejection. This result shows that, whilst NMDA does enhance synaptic responses of spinal neurones, this effect is little or no greater than for AMPA or kainate. Furthermore, the rapid recovery of nociceptive responses indicates that more than NMDA receptor activation alone is required to induce longer-term enhancement of nociceptive responses (hyperalgesia).
在麻醉大鼠的脊髓神经元上测试了兴奋性氨基酸（EAA）调节伤害性和非伤害性反应的能力。通过离子电泳喷射施加N-甲基-D-天冬氨酸（NMDA）、（RS）-α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）和海人酸，以将每个细胞的背景放电频率提高到约25个脉冲/秒。所有三种EAA均以相似程度增强了对有害热刺激、捏压刺激和无害轻拍刺激的反应，并且在EAA喷射终止后立即恢复到对照水平。该结果表明，虽然NMDA确实增强了脊髓神经元的突触反应，但这种作用与AMPA或海人酸相比几乎没有或没有更大。此外，伤害性反应的快速恢复表明，仅NMDA受体激活不足以诱导伤害性反应（痛觉过敏）的长期增强。
