Enhancement of tyrosine hydroxylase activity by Oxotremorine does not affect sleep in the rat

Marked enhancement of tyrosine hydroxylase (TH) activity was observed in the rostral pons of Wistar albino rats, 3 days after a single injection of Oxotremorine. TH activity in other brain areas, and regional levels of norepinephrine, dopamine, serotonin and 5-hydroxyindoleacetic acid were unaffected. Enhancement of TH activity did not affect length or number of REM episodes, or the amount of REM occurring in 24 hr. REM occurrence did not, thus, vary in accordance with activity of the rate-limiting enzyme for catecholamine synthesis. These data suggest that, although REM may reflect neuronal protein synthesis, REM is not part of a mechanism regulating the activity of enzymes in the pontine CA synthesis pathway.