Abstract
To define the function of Oxytocin receptor (OXTR) in vivo, we generated mice deficient in Oxtr gene (Oxtr-/-). Oxtr-/- mice showed no obvious defect in fertility or reproductive ability, however they showed several aberrations especially in their social behaviors such as male aggression, maternal behaviors and mother-offspring interaction. In addition, they also showed novel physiological dysfunctions caused by deficit of Oxtr gene, such as male specific obese and abnormal control of body temperature when they were exposed to cold. Similarly, slight obese in male and abnormal control of body temperature, when exposed to cold, was also observed in mice deficient in ligand Oxytocin (Oxt) gene. Recently, we newly generated Oxtr-Venus knock-in mice as a new tool to characterize the neurons expressing Oxtr and to further study the distribution of them in brain. We detected Venus-positive neurons at many nuclei, which were though to be involved in centers controlling social behaviors and temperature homeostasis. Moreover, administration of Oxytocin into median laphe, where many Venus positive neurons were detected, induced an increase of body temperature. These findings imply that Oxytocin/Oxytocin receptor system not only control social behaviors but also energy and temperature homeostasis. [J Physiol Sci. 2008;58 Suppl:S38]
