THE INTERACTION BETWEEN PERIAQUEDUCTAL GRAY AND NUCLEUS ACCUMBENS IN ACCELER-ATING THE RELEASE OF ENKEPHALINS AND β-ENDORPHIN

There is a growing body of evidence showing that periaqueductal gray (PAG) and nucleus accumbens (N. accumbens) play important roles in the modulation of nociception. In our previous study of the mechanisms of morphine analgesia we found that opioid antagonist naloxone injected into either of the two nuclei, PAG or N. accumbens, could