Localization of a metabotropic glutamate receptor, mGluR7, in axon terminals of presumed nociceptive, primary afferent fibers in the superficial layers of the spinal dorsal horn: an electron microscope study in the rat.
It was examined electron microscopically in the rat if a metabotropic glutamate receptor, mGluR7, might be localized in axon terminals of nociceptive, primary afferent fibers in laminae I and II of the spinal dorsal horn. Nociceptive nature of axon terminals showing mGluR7-like immunoreactivity (mGluR7-LI) was indicated by binding to the isolectin I-B4 from Griffonia simplicifolia (I-B4), or by substance P-like immunoreactivity (SP-LI). Axon terminals labeled with immunogold particles indicating mGluR7-LI were usually filled with round synaptic vesicles and were in asymmetric synaptic contact with dendritic or somatic profiles; occasionally they contained pleomorphic vesicles and were in symmetric synaptic contact with somatic profiles in lamina II. The double-labeling studies revealed that most of axon terminals with I-B4 labeling as well as a small population of axon terminals with SP-LI, showed mGluR7-LI. About one-third or much smaller population of axon terminals with mGluR7-LI in laminae I and II were labeled, respectively, with I-B4 or SP-LI; these were in asymmetric synaptic contact with dendritic profiles.
Li
H
H
Department of Morphological Brain Science, Faculty of Medicine, Kyoto University, Japan.
Ohishi
H
H
Kinoshita
A
A
Shigemoto
R
R
Nomura
S
S
Mizuno
N
N
D000818:Animals; D001369:Axons / Q000378:metabolism*; D008297:Male; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000378:metabolism*; D009412:Nerve Fibers / Q000378:metabolism; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D009619:Nociceptors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism* / Q000648:ultrastructure; D014018:Tissue Distribution
D018094:Receptors, Metabotropic Glutamate