Immunohistochemical study of delta and mu opioid receptors on synaptic glomeruli with substance P-positive central terminals in chicken dorsal horn.
In an attempt to clarify the mechanism underlying the regulation of the release of substance P (SP) from the central axon terminals of the synaptic glomeruli in lamina II of the dorsal horn, we examined the expression patterns of delta and mu opioid receptors (DOR and MOR) in relation to those of enkephalin (ENK) and SP in the synaptic glomeruli. DOR, MOR, ENK and SP immunoreactivities in lamina II of the dorsal horn in the chicken were examined by confocal laser scanning and electron microscopies. DOR immunoreactivity was localized in both SP-positive central terminals and peripheral elements, while MOR immunoreactivity was only localized in the peripheral elements of the synaptic glomeruli. Both of the peripheral DOR- and MOR-immunoreactive elements were shown to be vesicle-containing dendrites by electron microscopy. Dual immunohistochemistry indicated that DOR, MOR and ENK immunoreactivities were located in distinct peripheral elements. On the basis of present results, the possible roles of DOR and MOR in the regulation of the release of SP from the central axon terminals in the synaptic glomeruli are discussed.
Kawate
Toyoko
T
Department of Anatomy, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Tamaho, Yamanashi 409-3898, Japan. tkawate@yamanashi.ac.jp
Sakamoto
Hiroshi
H
Yang
Chunying
C
Li
Yongnan
Y
Shimada
Osamu
O
Atsumi
Saoko
S
D000818:Animals; D002645:Chickens; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D004745:Enkephalins / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D020671:Posterior Horn Cells / Q000378:metabolism* / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D013126:Spinal Nerve Roots / Q000378:metabolism* / Q000648:ultrastructure; D013373:Substance P / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology; D013572:Synaptic Vesicles / Q000378:metabolism / Q000648:ultrastructure
D004745:Enkephalins; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D013373:Substance P