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Effects of immobilization on rat liver tryptophan pyrrolase and brain 5‐hydroxytryptamine metabolism
Author(s) -
CURZON G.,
GREEN A. R.
Publication year - 1969
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1969.tb08507.x
Subject(s) - medicine , endocrinology , chemistry , probenecid , monoamine oxidase , allopurinol , cortisone , tryptophan , metabolism , serotonin , enzyme , biochemistry , amino acid , receptor
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 α‐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.