Differential effects of systemic versus intracranial injection of opiates on central, orofacial and lower body nociception: somatotypy in bulbar analgesia systems.
1 microgram morphine sulfate or 30 microgram [D-Ala2]-met-enkephalin microcannulated into the bulbar nuclei reticularis gigantocellularis and paragigantocellularis produced profound analgesia for orofacial thermal nociception, while having a smaller analgesic effect on tail-flick latency, and no effect on aversive stimulation thresholds in midbrain and in the spinal trigeminal nucleus (subnucleus caudalis). Systemic morphine (10 mg/kg) producing equivalently profound orofacial analgesia, profoundly affected tail-flick latency and trigeminal nuclear stimulation thresholds, while still failing to affect aversive midbrain stimulation threshold.
D000818:Animals; D001931:Brain Mapping; D004723:Endorphins / Q000494:pharmacology*; D004745:Enkephalins / Q000494:pharmacology* / Q000627:therapeutic use; D004924:Escape Reaction / Q000187:drug effects; D008297:Male; D008636:Mesencephalon / Q000187:drug effects* / Q000502:physiology; D009020:Morphine / Q000494:pharmacology* / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D051381:Rats; D012154:Reticular Formation / Q000187:drug effects* / Q000502:physiology
D004723:Endorphins; D004745:Enkephalins; D009020:Morphine