Date of Award


Document Type


Degree Name

Master of Arts




Morphine significantly impairs maternal behavior; N aloxone, an opiate antagonist, restores it. Maternal behavior is associated with c-fos expression, an immediate early gene product, in medial preoptic area (mPOA) of females. In this series of experiments, the effects of morphine and Naloxone on the expression of c-fos were examined. On postpartum day 5 or 6, females were injected with morphine or saline ( Exp. 1 ), or morphine+Naloxone or morphine+saline (Exp. 2) and placed back in the homepage, separated from their pups by a wire-mesh partition. Sixty minutes later processing for cfos immunohistochemistry commenced. The c-fos positive cells in a proscribed portion of mPOA were counted. Morphine-treated females had fewer c-fos cells in mPOA compared to saline-treated females. Further, morphine+Naloxone-treated females expressed more cfos cells compared to morphine+saline females. Morphine-treated females, therefore, may exhibit reductions in MB because of relative opiate-induced inactivation of areas of the brain devoted to the regulation of maternal behavior.

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