Morphine effects on activity and pain reactivity of developing mice with or without late prenatal oxazepam exposure.
Locomotor activity in a Varimex apparatus, hot-plate responding, and morphine effects (1 and 10 mg/kg IP) were assessed in 14-, 21-, 28-, and 70-day old mice. The development of hot-plate responding consisted mainly of a progressive increase of latencies and a parallel reduction of sensitivity to morphine. Morphine depressed activity at 14 days at the lower dose, had no effect at 21 days, and produced an adult-like hyperactivity at 28 days (10 mg/kg). Prenatal oxazepam (15 mg/kg, given per os twice daily on days 12-16 of pregnancy) did not influence hot-plate responding and morphine analgesia at any of the test ages. By contrast, the data on activity, besides replicating the response reduction at 14 days observed previously in an open-field test (Alleva et al. 1985), showed a delayed appearance of morphine hyperactivity in oxazepam mice.
D000375:Aging / Q000502:physiology; D000818:Animals; D005260:Female; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008960:Models, Psychological; D009020:Morphine / Q000494:pharmacology*; D010076:Oxazepam / Q000494:pharmacology*; D010146:Pain / Q000523:psychology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011930:Reaction Time / Q000187:drug effects
D010076:Oxazepam; D009020:Morphine