Lack of evidence for mu-opioid regulation of a socially mediated separation response.

摘要: Maternal potentiation of ultrasonic vocalization (USV) occurs when, after a brief contact with the dam, reisolated infant rats produce USV at rate as much double or triple their calling in initial isolation. Potentiation most robustly when dam is alert (active) but also elicited by an anesthetized (passive). The possible role mu-opioid receptors control both active and passive was tested using mu-preferring receptor agonist morphine antagonist naltrexone. While high levels did suppress second isolation, neither nor demonstrated effect specific to potentiation. That is, no dose naltrexone suppressed enhanced response only highest prevented dam. results do not support possibility that activation mu-receptors endogenous opioids regulates increase caused maternal