title: Effects of aging on pain responses and analgesic efficacy of morphine and clonidine in rats.
mesh_terms: D000375:Aging; D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009115:Muridae; D009619:Nociceptors / Q000187:drug effects*; D012684:Sensory Thresholds
chemical_list: D009020:Morphine; D003000:Clonidine