title: Antinociceptive defect of beige-J mice reversed by i.c.v. IP3 or myo-inositol.
abstract: The C57BL/6J-bgJ/bgJ (beige-J) mutation imparts a blunted response to intracerebroventricular (i.c.v.) morphine in the tail-flick test, without altered micro-opioid receptor number or morphine affinity. We now report that co-administration of IP3 (36.1 nmol) restored morphine responsiveness of beige-J mice to essentially that of normal littermates (bg+/bg-; ED50 = 3.9 and 3.5 nmol, respectively). IP3 had no effect on morphine-induced antinociception in control animals. Neither myoinositol at 36.1 nmol nor IP6 at the highest testable dose (4.5 nmol) had a similar effect. Myo-inositol at 5.5 mumol restored beige-J responsiveness to that of littermates. These findings implicate some component of the phosphoinositide cycle in the antinociceptive defect of beige-J mice.
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007276:Injections, Intraventricular; D007294:Inositol / Q000008:administration & dosage / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009020:Morphine / Q000494:pharmacology; D010146:Pain / Q000235:genetics* / Q000523:psychology; D010147:Pain Measurement / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D015290:Second Messenger Systems / Q000502:physiology
chemical_list: D000700:Analgesics; D007294:Inositol; D009020:Morphine; D015544:Inositol 1,4,5-Trisphosphate