BEHAVIORAL CHARACTERIZATION OF MICE PACKING THE 5-HT1B RECEPTOR

Serotonin (5-hydroxytryptamine, 5-HT) is a neuromodulator that is involved in a number of mood disorders such as depression, anxiety, and impulsive violence. In an attempt to dissect the contribution of individual 5-HT receptor subtypes to behavior, the authors have generated, by homologous recombination, mutant mice lacking the 5HT1B receptor. These mice did not exhibit any obvious developmental or behavioral defect; however, the hyperlocomotor effect of the 5-HT1A/5-HT1B agonist RU24969 was completely absent in mutant mice, indicating that this effect is mediated by 5HT1B receptors. Moreover, when confronted with an intruder, isolated mutant mice attacked the intruder faster and more intensely than wild-type mice, suggesting an involvement of 5-HT1B receptors in the modulation of aggressive behavior. These data might be related to the fact that a class of 5-HT1 agonists, termed serenics, have antiaggressive properties, and with the findings that certain impulsive aggressive behaviors are associated with deficits in central serotonin.