[Influence of cooling motor cortex on the inhibitory effect of stimulation of SII on nociceptive responses in ILN neurons].
Fibers from the cortical somatosensory area II (SII) or motor cortex (MCtx) to intralaminar nuclei (ILN) have been proven to exist, and SII was found to be connected with MCtx by cortico-cortical fibers. The present work was undertaken to study whether MCtx participated in SII producing descending modulation of ILN. All experiments were performed on sodium pentobarbitone anaesthetised cats. Single unit activities of ILN neurons were extracellularly recorded by glass microelectrodes. The effects of stimulating SII on nociceptive responses of ILN neurons were observed before and after cooling MCtx. The nociceptive responses of ILN neurons were attenuated by stimulating SII. There was a statistically significant difference at 0'-2' after the stimulation (n = 14, P < 0.05). The inhibitory effect of stimulating SII was reduced after cooling MCtx (19 degrees C-20 degrees C) in 8 neurons, and abolished in other neurons when the temperature was below 18 degrees C. MCtx was involved in SII producing descending modulation of ILN.
Zheng
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X
Dept. of Physiology, China Academy of Traditional Chinese Medicine, Beijing.
Chen
Z
Z
Shi
H
H
Xu
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W
D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D007036:Hypothermia, Induced; D009044:Motor Cortex / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D013787:Thalamic Nuclei / Q000502:physiology*