The effects of postmortem delay on mu, delta and kappa opioid receptor subtypes in rat brain and guinea pig cerebellum evaluated by radioligand receptor binding.
Studies of human and animal central nervous system receptor degradation and measurement postmortem are important as human tissue can rarely be collected under ideal experimental conditions. Correlating the change in binding of opioid receptor subtypes over time will help define the conditions under which human studies may be valid. The present study was designed to investigate the rate at which opioid receptor subtypes degrade postmortem. Brains from rats or cerebelli from guinea pigs were kept at 22 degrees C or 4 degrees C at times from zero to 24 hours to simulate two common human collection techniques; room temperature and morgue refrigeration. Tissue homogenates from these brains were analysed for mu1, mu2, delta, kappa1 and kappa3 opioid receptor binding using standard radioligand binding techniques. At room temperature mu1, mu2 and delta opioid receptor binding was reduced between 6 and 12 hours, whereas kappa1 and kappa3 binding was reduced after 24 hours. At 4 degrees C mu1, mu2, delta, kappa1 and kappa3 binding remained constant over the 24 hour period.
Paul
D
D
Department of Pharmacology, LSU Medical Center, New Orleans, LA 70112, USA. dpaul@lsumc.edu
Gauthier
C A
CA
Minor
L D
LD
Gonzales
G R
GR
D000818:Animals; D044482:Benzeneacetamides; D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D016308:Enkephalin, Leucine-2-Alanine / Q000378:metabolism; D004745:Enkephalins / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D009270:Naloxone / Q000378:metabolism; D011180:Postmortem Changes; D011759:Pyrrolidines / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D017473:Receptors, Opioid, kappa / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D014316:Tritium
D044482:Benzeneacetamides; D004745:Enkephalins; D011759:Pyrrolidines; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D014316:Tritium; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009270:Naloxone; D016308:Enkephalin, Leucine-2-Alanine; C045444:U 69593