Immunofluorescent identification of a delta (delta)-opioid receptor on primary afferent nerve terminals.
Antisera were produced against synthetic peptides predicted from the recent cloning of a delta opioid receptor, DOR-1. Confocal microscopic examination of immunostained spinal cord sections revealed that DOR-1 immunoreactive (-ir) nerve fibers and terminals form a moderately dense plexus within the superficial dorsal horn of rats and mice. These fibers decreased dramatically following dorsal rhizotomy and consistent with these observations a population of small diameter neurons in ganglia exhibited DOR-1-ir. DOR-1-ir ganglion neurons were also immunoreactive for calcitonin gene-related peptide (CGRP), and their terminals in the spinal cord contained both CGRP- and DOR-1-ir, the latter presumably located as a 'presynaptic' receptor. Interestingly, terminals containing DOR-1-ir appeared to be closely apposed by fibers and terminals containing enkephalin (ENK)-ir, which suggests that ENK may be a physiologically relevant ligand for the receptor encoded by DOR-1, and that DOR-1 may act to regulate the release of transmitters from small diameter primary afferent neurons.
Dado
R J
RJ
Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis 55455.
Law
P Y
PY
Loh
H H
HH
Elde
R
R
D000818:Animals; D004745:Enkephalins / Q000276:immunology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005727:Ganglia, Spinal / Q000276:immunology / Q000378:metabolism; D015151:Immunoblotting; D008297:Male; D051379:Mice; D009411:Nerve Endings / Q000276:immunology / Q000378:metabolism*; D009412:Nerve Fibers / Q000378:metabolism; D009475:Neurons, Afferent / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000276:immunology / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism
D004745:Enkephalins; D017465:Receptors, Opioid, delta