Behavioral study on the gracile axonal dystrophy (GAD) mutant mouse.
We investigated motor function and pain sensation in the gracile axonal dystrophy (GAD) mutant mouse, using the tail-flick test and the rotarod test. GAD (gad/gad) and normal sib mice (gad/+ or +/+) were used between 5 and 11 weeks of age, during which time the behavioral signs of GAD mice shifted from sensory ataxia (about 4 to 8 weeks of age) to paresis (after about 9 weeks of age). In the tail-flick test, significant shortening of latency was observed at 6 and 8 weeks of age in female GAD mice, in comparison with normal female mice. This may be related to dysfunction or degeneration of axons in the fasiculus gracilis, whose collaterals are thought to control the transmission of nociceptive information. In the rotarod test, a cumulative chi 2 test showed significant reduction in the performance times of GAD mice beginning at 5 and 6 weeks of age in males and females, respectively, indicating that the rotarod test can detect the development of motor incoordination as early as these ages. The performance times of GAD mice dropped sharply from 9 weeks of age onwards, and this is believed to reflect the progression of paresis. The rotarod test therefore appears to be a good method of quantifying behavioral changes in GAD mice and to be applicable both to objective selection of GAD mice before 8 weeks of age and to evaluation of drugs to treat ataxia or paresis.
Yamazaki
K
K
Tsukuba Research Laboratories, Eisai Co., Ltd., Ibaraki, Japan.
Nakazawa
T
T
Matsunaga
M
M
Kumazawa
A
A
Kaneko
T
T
Wakabayashi
T
T
D000367:Age Factors; D000818:Animals; D001259:Ataxia / Q000188:drug therapy / Q000503:physiopathology; D004341:Drug Evaluation; D005260:Female; D008297:Male; D051379:Mice; D008818:Mice, Neurologic Mutants; D009043:Motor Activity; D010291:Paresis / Q000188:drug therapy / Q000503:physiopathology