French pharmaceutical company Sanofi-Aventis is testing SSR149415, a drug that blocks vasopressin receptors in the limbic system, for use in treating generalized anxiety disorder. In rats, the compound reduced the negative effects of stress. SSR149415 acts specifically on vasopressin B receptors, or V1b, which are located in the brain.
Vasopressin, a close cousin of oxytocin, seems to be involved in learning and social memory. While men and women both produce vasopressin, testosterone increases the brain’s receptivity to it, just as estrogen increases the effects of oxytocin.
The drug seems to reduce anxiety and have antidepressant effects without impairing motor activity or messing up sleep patterns.
Scientists think SSR149415 acts on vasopressin receptors in the neurons in the amygdala, septum, hippocampus, or hypothalamus, regions that are associated with the integration and processing of stressful stimuli.