Effect of chronic administration of morphine on the expression of bovine adrenal medulla 22-like immunoreactivity in the spinal cord of rats.
The aim of the present study was to investigate the effects of chronic administration of morphine on the expression of an endogenous opioid peptide in the spinal dorsal horn. Bovine adrenal medulla 22-like immunoreactivity (BAM22-IR) was found in the superficial layers of the spinal cord. Intrathecal (i.t.) administration of morphine (20 microg) for 6 days, but not 2 days, significantly reduced the expression of BAM22-IR whereas i.t. administration of saline for 2 and 6 days did not alter the expression of BAM22-IR. The present study suggests that reduction of BAM22-IR in the spinal cord is involved in the development of morphine tolerance.
Chen
Peiwen
P
College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian, PR China.
Liu
Yushan
Y
Hong
Yanguo
Y
D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000818:Animals; D002417:Cattle; D004361:Drug Tolerance; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000378:metabolism; D007150:Immunohistochemistry; D007278:Injections, Spinal; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D020671:Posterior Horn Cells / Q000187:drug effects / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors
D000701:Analgesics, Opioid; D011498:Protein Precursors; D004744:Enkephalin, Methionine; C028837:BAM 22P; D009020:Morphine