Effects of immobilization on rat liver tryptophan pyrrolase and brain 5-hydroxytryptamine metabolism.
1. Rat liver tryptophan pyrrolase increased on immobilization. The concentration of 5-hydroxyindoleacetic acid in the brain also rose and that of 5-hydroxytryptamine fell.2. When adrenalectomized rats were immobilized pyrrolase activity did not rise and brain 5-hydroxytryptamine concentration fell to a lesser extent but the 5-hydroxyindoleacetic acid concentration rose as in intact animals.3. When intact rats were injected with the pyrrolase inhibitor Allopurinol both the increase of pyrrolase and the fall of 5-hydroxytryptamine on immobilization were less prominent but the concentration of 5-hydroxyindoleacetic acid rose as before. Allopurinol did not affect the changes in immobilized adrenalectomized rats.4. Immobilization thus appears to cause (a) decreased brain 5-hydroxytryptamine synthesis resulting from pyrrolase induction and (b) increased 5-hydroxytryptamine breakdown by a more direct effect on the brain. Results of experiments on rats injected with lysergic acid diethylamide, and with alpha-methyltryptophan or probenecid are consistent with the above interpretation.5. The 5-hydroxytryptamine and 5-hydroxyindoleacetic acid changes were maximal after 5-6 hours' immobilization and became less on more prolonged immobilization, which suggests regulatory changes.
D000315:Adrenalectomy; D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D004790:Enzyme Induction; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D007103:Immobilization; D008099:Liver / Q000201:enzymology*; D008238:Lysergic Acid Diethylamide / Q000494:pharmacology; D008297:Male; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D013997:Time Factors; D014364:Tryptophan / Q000494:pharmacology; D014366:Tryptophan Oxygenase / Q000032:analysis* / Q000037:antagonists & inhibitors
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D000493:Allopurinol; D014364:Tryptophan; D008238:Lysergic Acid Diethylamide; D014366:Tryptophan Oxygenase; D011339:Probenecid