INFLUENCE OF OCYTOCIN ON REGIONAL UPTAKE OF [H-3]OROTIC ACID BY RAT-BRAIN

Abstract

The uptake of the RNA precursor [3H] orotic acid by 18 brain regions of male rats was measured after intracarotid injection and a survival time of 15 s. Oxytocin added to the injected solutions (final concentrations: 1-1000 mU[milliunits]/ml) caused a dose-dependent enhancement of tracer uptake by 11 areas. Some of these regions (e.g., hippocampus) are thought to be involved in the behavioral effects of vasopressin and other peptide hormones. Results of experiments in which the net uptake of 3H water was used as a measure of relative blood flow led to the conclusion that the blood-brain barrier permeability to [3H] orotic acid rather than the cerebral blood flow is changed by oxytocin. An enhanced precursor supply caused by oxytocin might contribute to the influence of this peptide hormone on memory consolidation.