EFFECT OF BRAIN STEM LESIONS ON TYROSINE AND TRYPTOPHAN HYDROXYLASES IN VARIOUS STRUCTURES OF TELENCEPHALON OF CAT

Unilateral lesions of the ventromedial tegmental area of the upper brain stem are associated with decreased concentrations of tyrosine and tryptophan hydroxylases without any reduction of succinic dehydrogenase in different telencephalic structures on the corresponding side of the brain in the cat. Unilateral lesions of the intralaminar nuclei of the thalamus have no effect on the concentrations of any of these enzymes in the same tissues. These results indicate that the syntheses of dopamine and serotonin in the striatal and other tissues are dependent on the integrity of separate neuronal systems originating in specific cell groups of the brain stem. © 1969.