Ketamine, a drug abused for its psychedelic effects, alters movement differently depending on a mouse's age, strain, and dose. Adolescent and adult male mice from two strains, C57BL/6J and BALB/c, were given ketamine at 0, 25, or 50 mg/kg after a 30-minute baseline. In C57BL/6J mice, both age groups showed significantly increased distance traveled and speed after ketamine, but BALB/c mice did not. The higher dose delayed the onset of hyperlocomotion compared to the lower dose. Adolescent C57BL/6J mice showed greater locomotor activation than adults, a difference not seen in BALB/c mice. These results indicate that sensitivity to ketamine's effects on movement is biologically determined.
Ketamine, a drug that blocks NMDA receptors and produces schizophrenia-like effects, causes different behavioral responses depending on the mouse strain and dose. Adolescent mice from four strains—C57BL/6J, DBA, BALB/c, and 129S1—received ketamine injections of 0, 25, or 50 mg/kg, and their movement in an open field was tracked. Before and after treatment, locomotor activity varied significantly among strains, with C57BL/6J mice most active and 129S1 mice least active. Ketamine dose-dependently increased movement in C57BL/6J mice, caused brief excitation in DBA mice at 25 mg/kg, delayed excitation in BALB/c mice at 50 mg/kg, and minimal changes in 129S1 mice. These findings demonstrate that genetic background and dose modulate ketamine sensitivity during adolescence.