| Abstract: | The effect of intraventricular β-endorphin-(1–27) on the spinal release of Met-enkephalin induced by intraventricular β-endorphin was studied using the intrathecal superfusion technique in urethane anesthetized rats. Intraventricular injection of β-endorphin at a dose of 15 μg released Met-enkephalin from the spinal cord. This release of Met-enkephalin induced by β-endorphin was significantly reduced by β-endorphin-(1–27), 60 μg, injected intraventricularly. Injection of β-endorphin (1–27) itself did not cause any release of Met-enkephalin. The finding is in line with the previous report that β-endorphin (1–27) inhibited the analgesia induced by β-endorphin. |
