Effects of interdose interval on ambulatory sensitization to methamphetamine, cocaine and morphine in mice.
To determine the minimum interdose interval for induction of ambulatory sensitization to methamphetamine, cocaine and morphine, 3 sets of 5 groups of mice were treated with either methamphetamine (2 mg/kg s.c.), cocaine (10 mg/kg s.c.) or morphine (10 mg/kg s.c.) 3 times at intervals of 3, 6, 12, 24 or 48 h, and then 2 times at intervals of 3 days in all groups. During the first 3 administrations of both methamphetamine and cocaine, interdose intervals of 3-12 h did not produce a significant change in the ambulatory stimulation. However, 3 repeated administrations of morphine with interdose intervals of 3 and 6 h, but not 12 h, caused tolerance to the ambulatory stimulant effect. The administration of all drugs with interdose intervals of 24 and 48 h produced ambulatory sensitization. Furthermore, following the fourth and fifth administrations of each drug, all groups of mice demonstrated sensitization. These results indicate that an interdose interval of 24 h or longer is required for induction of ambulatory sensitization to methamphetamine, cocaine and morphine.
Kuribara
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Department of Neurobiology and Behavior, Gunma University School of Medicine, Maebashi, Japan.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage* / Q000494:pharmacology; D003042:Cocaine / Q000008:administration & dosage* / Q000494:pharmacology; D004334:Drug Administration Schedule; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage* / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D009020:Morphine / Q000008:administration & dosage* / Q000494:pharmacology; D009294:Narcotics / Q000008:administration & dosage* / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013268:Stimulation, Chemical
D000697:Central Nervous System Stimulants; D009294:Narcotics; D008694:Methamphetamine; D009020:Morphine; D003042:Cocaine