ENHANCED AGGRESSIVE-BEHAVIOR IN MICE LACKING 5-HT1B RECEPTOR

The neuromodulator serotonin (5-hydroxytryptamine, 5-HT) has been asso ciated with mood disorders such as depression, anxiety, and impulsive violence. To define the contribution of 5-HT receptor subtypes to beha vior, mutant mice lacking the 5-HT1B receptor were generated by homolo gous recombination. These mice did not exhibit any obvious development al or behavioral defects. However, the hyperlocomotor effect of the 5- HT1A/(1B) agonist RU24969 was absent in mutant mice, indicating that t his effect is mediated by 5-HT1B receptors. Moreover, when confronted with an intruder, mutant mice attacked the intruder faster and more in tensely than did wild-type mice, suggesting the participation of 5-HT1 B receptors in aggressive behavior.