NEUROLEPTIC DRUGS ACTIVATE TYROSINE-HYDROXYLASE OF RETINAL AMACRINE CELLS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 218  (2) , 390-394
Abstract
Tyrosine hydroxylase of retinal dopamine-containing amacrine cells (rat) exists in 2 states, a basal state in the dark and an activated state in the light. Treatment with haloperidol, chlorpromazine, clozapine or domperidone results in activation of tyrosine hydroxylase in the dark. With haloperidol, the magnitidue of the activation was dose-related. After single dose of haloperidol (3 mg/kg i.p.) enzyme activation persisted for at least 3 h. By kinetic analysis, activation was characterized as a decrease in the Km for the pteridine cofactor. Activation by light induces similar kinetic changes. Apparently, the dopaminergic system of retina responds to neuroleptic drug treatment similar to the nigrostriatal dopaminergic system.