title: Diurnal differences in opioid peptide levels correlated with nociceptive sensitivity.
mesh_terms: D000818:Animals; D001681:Biological Assay; D001921:Brain / Q000378:metabolism*; D002940:Circadian Rhythm; D004723:Endorphins / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D051379:Mice; D009619:Nociceptors / Q000378:metabolism*; D011863:Radioimmunoassay / Q000379:methods; D011869:Radioligand Assay; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D004723:Endorphins; D004745:Enkephalins