The effect of a kainate GluR5 receptor antagonist on responses of spinothalamic tract neurons in a model of peripheral neuropathy in primates.
The responses of antidromically identified spinothalamic tract (STT) neurons to mechanical and thermal stimuli were compared in anesthetized normal and neuropathic monkeys before and after administration of a GluR5 kainate receptor antagonist (LY382884) into the spinal cord dorsal horn through a microdialysis fiber. Peripheral neuropathy was induced by tight ligation of the L7 spinal nerve 13-15 days prior to the experiment. STT neurons recorded in the animals with neuropathy showed increased responsiveness to weak mechanical stimuli and to heating and cooling of the skin compared to STT cells in normal animals. In both normal and the neuropathic monkeys the responses of the STT neurons to mechanical and thermal stimuli were attenuated by LY382884 application in a concentration-dependent manner. Intraspinal application of LY382884 in the neuropathic animals led to a potent reduction of those responses of the STT neurons that were aggravated by the peripheral neuropathy (weak mechanical, heat and innocuous cooling stimuli). These results suggest that kainate receptors are involved in synaptic activation of STT cells in the normal state and may also play an important role in pathological pain states such as peripheral neuropathy in primates. Kainate receptor antagonists could thus be useful for the treatment of certain forms of allodynia and hyperalgesia.
Palecek
J
J
Institute of Physiology, Academy of Sciences, Prague, Czech Republic.
Neugebauer
V
V
Carlton
S M
SM
Iyengar
S
S
Willis
W D
WD
D000818:Animals; D003080:Cold Temperature; D004195:Disease Models, Animal; D006358:Hot Temperature; D006930:Hyperalgesia / Q000188:drug therapy; D007546:Isoquinolines / Q000494:pharmacology*; D008252:Macaca fascicularis; D008297:Male; D009474:Neurons / Q000187:drug effects; D010523:Peripheral Nervous System Diseases / Q000188:drug therapy*; D010812:Physical Stimulation; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors*; D013133:Spinothalamic Tracts / Q000166:cytology*
D007546:Isoquinolines; D018092:Kainic Acid Receptors; C400802:LY382884