Neurokinin receptor 1-expressing spinal cord neurons in lamina I and III/IV of postnatal rats receive inputs from capsaicin sensitive fibers.
Dorsal horn neurons expressing receptor for substance P (SP), the neurokinin 1 (NK1) receptor, play an important role in transmission and processing of nociceptive stimuli. To identify and study these neurons in the rat spinal cord slice preparation, we used fluorescence-conjugated SP to label NK1 receptor-expressing neurons. Labeled neurons in lamina I and III/IV were patch clamped and the vanilloid receptor 1 (TRPV1) agonist, capsaicin, was applied to evoke glutamate release from central terminals of peripheral nociceptors. Capsaicin induced an increase in the frequency of miniature excitatory postsynaptic currents in 73% of lamina I and 43% of lamina III/IV neurons expressing NK1-receptor indicating that these neurons receive direct input from capsaicin and heat sensitive nociceptors.
Labrakakis
Charalampos
C
Department of Physiology and Cellular Biophysics and the Center of Neurobiology and Behavior, Columbia University, New York, NY, USA. c.labrakakis@crulrg.ulaval.ca
MacDermott
Amy B
AB
D000818:Animals; D000831:Animals, Newborn; D002211:Capsaicin / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D009412:Nerve Fibers / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D020671:Posterior Horn Cells / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D018040:Receptors, Neurokinin-1 / Q000032:analysis / Q000096:biosynthesis*
D018040:Receptors, Neurokinin-1; D002211:Capsaicin