Evaluation of aggressiveness of female mice using a semi-automated apparatus for measurement of aggressive biting behavior toward an inanimate object.
BACKGROUND
Most laboratory research on aggressive behavior has focused on intraspecific intermale aggression tests. The intraspecific confrontation is not available for the evaluation of female aggressiveness, since androgens are critical for maintenance of this behavior, whereas aggressive biting behavior toward inanimate objects (ABI) occurs in both males and females.


METHODS
We propose an experimental method for evaluating female aggressiveness. We improved the previously developed semi-automated apparatus (Aggression Response Meter, ARM) to apply it to measurement of female ABI, and measured changes of ABI in stressed mice and drug actions on ABI.


RESULTS
ABI assessment was performed daily in sexually mature female mice using ARM. The intensity and number of ABI in one session did not significantly change during an estrous cycle, suggesting that ABI is not influenced by the dynamics of sex hormones. Additional female mice were socially isolated for 7 weeks and then re-socialized for 2 weeks, and ABI was monitored weekly. ABI significantly increased during the isolation period, and then significantly decreased during re-socialization; both were time-dependent. In prolonged-isolated aggressive mice, a serotonin 1A receptor agonist, buspirone, significantly decreased ABI.


CONCLUSIONS
There are no experimental methods or apparatus available for evaluating female aggressiveness using one individual repeatedly. We could measure ABI semi-quantitatively using the ARM.


CONCLUSIONS
ABI is a useful behavioral paradigm in the evaluation of aggressiveness in female mice, regardless of the estrous cycle, and can also be used for evaluating the actions of drugs on aggressiveness.
Department of Clinical Psychology, Graduate School of Human Science, Kagoshima Immaculate Heart University, 2365 Amatatsu-cho, Satsuma-Sendai 895-0011, Japan; Department of Morphological Science, Field of Neurology, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan. Electronic address: kuchiiwa@m.kufm.kagoshima-u.ac.jp.
Toshiko
T
Kuchiiwa
Department of Morphological Science, Field of Neurology, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan. Electronic address: satoshik@m3.kufm.kagoshima-u.ac.jp.
Satoshi
S
Kuchiiwa
D000374:Aggression / Q000187:drug effects / Q000502:physiology / Q000523:psychology; D000818:Animals; D057205:Automation, Laboratory / Q000295:instrumentation* / Q000379:methods*; D002065:Buspirone / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical / Q000295:instrumentation / Q000379:methods; D017097:Electric Impedance; D030762:Estrous Cycle; D005260:Female; D051379:Mice / Q000502:physiology / Q000523:psychology; D011581:Psychological Tests; D011619:Psychotropic Drugs / Q000494:pharmacology; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism; D058825:Serotonin 5-HT1 Receptor Agonists / Q000494:pharmacology; D012934:Social Isolation / Q000523:psychology; D013315:Stress, Psychological / Q000503:physiopathology; D014621:Vagina / Q000502:physiology
D011619:Psychotropic Drugs; D058825:Serotonin 5-HT1 Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D002065:Buspirone
Aggressive biting behavior; Female estrous cycle; Isolation-induced aggression; Psychotropic drug evaluation; Serotonin 1A receptor agonist; Sex difference