Substance P-mediated slow excitatory postsynaptic potential elicited in dorsal horn neurons in vivo by noxious stimulation. |
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| Authors: | Y De Koninck and J L Henry |
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| Affiliation: | Department of Physiology, McGill University, Montréal, Québec, Canada. |
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| Abstract: | ![]()
The original proposal that substance P is involved in the regulation of nociceptive information at the first sensory synapse in the spinal cord has been substantiated by a wide range of evidence, but definitive support has been lacking, due primarily to the lack of evidence that a specific nociceptive response in the dorsal horn can be blocked by a substance P antagonist. Here, we present evidence that CP-96,345, a specific substance P (NK-1) receptor antagonist, selectively blocks a slow, prolonged excitatory postsynaptic potential following noxious cutaneous stimulation or a train of intense electrical stimuli to sensory nerves but does not affect the response to innocuous input or the brief response to single electrical stimuli to C fibers. These results indicate the specific involvement of substance P in the mediation of a prolonged after-excitation to noxious stimulation. This may have important implications for the etiology and treatment of chronic pain and for plastic changes in nociceptive pathways. |
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