The elucidation of role of motor neurons or pain pathways of the spinal cord in analgesia, muscle reluxation, and immobility as general anesthetic factors

点击翻译按钮获取中文摘要

The role of substance P (SP) of the spinal cord in immobility as one of the general anesthetic factors was studied. Dexmedetomidine and morphine inhibit SP release from primary afferent neurons in the spinal cord. The selective N-methyl-D-aspartate (NMDA) channel blocker MK-801 is known to induce no loss of the righting reflex (LORR) and to stimulate catecholaminergic neurons in rodents, playing a crucial role in arousal. MK-801 in combination with a small dose of the dopamine (DA) receptor antagonist haloperidol dose-dependently produced LORR, but not immobility. Dexmedetomidine and morphine induced immobility in animals treated with MK-801 plus haloperidol, which then lost their righting reflex. These findings suggest that the immobility involves the inhibition of SP release in the spinal cord.