Effects of acute agonist treatment on subcellular distribution of kappa opioid receptor in rat spinal cord.
We investigated whether acute treatment with agonists affected the subcellular distribution of kappa opioid receptor (KOPR) in the dorsal horn of the rat lumbar spinal cord by using immunoelectron microscopy. Rats were injected intrathecally (i.t.) with U50,488H (100 nmole), dynorphin A(1-17) (15 nmole), or vehicle. The doses chosen have been shown to induce antinociception. Rats were perfused transcardially 30 min later, and lumbar spinal cords were removed and processed for electron microscopic analysis. KOPR was stained with KT-2, a specific polyclonal antibody against the rat/mouse KOPR(371-380) peptide, followed by gold-labeled secondary antibody and silver intensification. The silver grains were present in axons, terminals, dendrites, and somata, and the association with plasma membranes was quantified in dendrites, because KOPR immunoreactivity was most frequently observed in these profiles. In vehicle-treated rats, approximately 27% of KOPR immunoreactivity was associated with plasma membranes. U50,488H, i.t., did not cause a significant change in the percentage of KOPR present on plasma membranes, whereas dynorphin A, i.t., significantly decreased cell surface KOPR to approximately 19%. In summary, these data indicate that U50,488H and dynorphin A differentially regulate the subcellular distribution of endogenous KOPR.
Wang
Yulin
Y
Department of Pharmacology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA.
Xu
Wei
W
Huang
Peng
P
Chavkin
Charles
C
Van Bockstaele
Elisabeth J
EJ
Liu-Chen
Lee-Yuan
LY
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D002404:Catheterization; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004399:Dynorphins / Q000494:pharmacology*; D005453:Fluorescence; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D007278:Injections, Spinal; D008159:Lumbar Vertebrae; D008297:Male; D016253:Microscopy, Immunoelectron; D020671:Posterior Horn Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000819:agonists* / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure
D017473:Receptors, Opioid, kappa; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D004399:Dynorphins