The effects of morphine on the accumulation of homovanillic and 5-hydroxyindoleacetic acids in the choroid plexus of rats.
1 Choroid plexus obtained from the lateral ventricles of the rat actively accumulated homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA). 2 Morphine 5 X 10(-6) M to 5 X 10(-4)M potentiated 5-HIAA accumulation but did not affect HVA accumulation. Levorphanol and dextorphan had little effect. 3 Naloxone at high concentrations inhibited both HVA and 5-HIAA accumulation. 4 Glutamic acid, glycine, and arginine also decreased 5-HIAA accumulation, but lysine, tryptophan, and aspartic acid had no effect. 5 Probenecid, naloxone, arginine, glycine, and tryptophan blocked the increase of 5-HIAA accumulation induced by morphine. 6 Acute or chronic morphine treatment did not increase the accumulation of 5-HIAA. 7 These results suggest that the increase of 5-HIAA or HVA in brain by morphine is not due to the inhibition of the elimination of these metabolites from the choroid plexus.
D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D002831:Choroid Plexus / Q000187:drug effects / Q000378:metabolism*; D004347:Drug Interactions; D005260:Female; D006719:Homovanillic Acid / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism*; D009019:Morphinans / Q000494:pharmacology; D009020:Morphine / Q000494:pharmacology*; D010648:Phenylacetates / Q000378:metabolism*; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D013997:Time Factors
D000596:Amino Acids; D009019:Morphinans; D010648:Phenylacetates; D006897:Hydroxyindoleacetic Acid; D009020:Morphine; D011339:Probenecid; D006719:Homovanillic Acid