The repeated administration of ketamine induces an enhancement of its stimulant action in mice.
The modification of the stimulant and motor-incoordinate actions of ketamine induced by repeated administration was investigated by means of ambulatory activity and rota-rod performance in mice, respectively. Ketamine (12.5, 25 and 50 mg/kg, s.c.) increased the mouse's ambulation in a dose-dependent manner, and the repeated 5-times administration at 3- to 4-day intervals enhanced the increment effect. However, a disruption of the rota-rod performance by ketamine was not modified by the repeated treatment. These results suggest that a reverse tolerance to the stimulant action of ketamine is produced, and that a tolerance to its motor-incoordinate action may not cause the enhancement.
Uchihashi
Y
Y
Division for Behavior Analysis, Gunma University School of Medicine, Maebashi, Japan.
Kuribara
H
H
Morita
T
T
Fujita
T
T
D000818:Animals; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects; D004856:Postural Balance / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects
D000697:Central Nervous System Stimulants; D007649:Ketamine