The relationship between neurokinin-1 receptor and substance P in the medullary dorsal horn: A light and electron microscopic immunohistochemical study in the rat Journal Article


Author(s): Li, Jin-Lian; Wang, Dan; Kaneko, Takeshi; Shigemoto, Ryuichi; Nomura, Sakashi; Mizuno, Noboru
Article Title: The relationship between neurokinin-1 receptor and substance P in the medullary dorsal horn: A light and electron microscopic immunohistochemical study in the rat
Affiliation
Abstract: The synaptic relationship between substance P (SP) and its receptor, i.e. neurokinin-1 receptor (NK1R), was examined in the superficial laminae of the caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) of the rat. For confocal laser-scanning microscopy, double-immunofluorescence histochemistry for NK1 and SP was performed. In electron microscopic double-immunolabeling study, immunoreactivity for NK1R was detected with the silver-intensified gold method, while immunoreactivity for SP was detected with peroxidase immunohistochemistry. SP-immunoreactive axon terminals were observed to be in synaptic (mostly asymmetric) contact with NK1R-immunoreactive neuronal profiles in lamina I and lamina IIo. Although some SP-immunoreactive axon terminals were in synaptic contact with NK1R-immunoreactive sites of plasma membranes, NK1R-immunoreactivity was observed at both synaptic and non-synaptic sites of plasma membrane. Thus, SP released from axon terminals might not only act on NK1Rs facing the SP-containing axon terminals, but also diffuse in the extracellular fluid for distances larger than the synaptic cleft to act on NK1Rs at some distances from the synaptic sites.
Keywords: Immunohistochemistry; NK1; Spinal trigeminal nucleus; Substance P; Substance P receptor; Volume transmission
Journal Title: Neuroscience Research
Volume: 36
Issue 4
ISSN: 0168-0102
Publisher: Elsevier  
Date Published: 2000-04-01
Start Page: 327
End Page: 334
DOI: 10.1016/S0168-0102(00)00095-X
Open access: no