we studied the effect of opiates acting preferentially on mu receptors , like morphine , methadone and fentanyl ( mu agonists ) and on kappa receptors , like u50,488 , bremazocine and tifluadom ( kappa agonists ) on the release of dopamine ( da ) and of its metabolites , dihydroxyphenylacetic acid and homovanillic acid , from the nucleus accumbens and from the dorsal caudate of freely moving rats using brain dialysis coupled to high-performance liquid chromatography with electrochemical detection .
C0028633
nucleus accumbens
C0006104
brain