Beta-adrenergic influence on brain concentrations of monoamine precursors.

The beta-adrenergic agonist isoprenaline: Causes a decrease in most amino acids in plasma. Changes the relation between the large neutral amino acids in plasma in favor of tyrosine and Try. Causes an increase in brain concentrations of tyrosine and Try. Causes an increase in brain concentrations of DOPA and Try after the administration of these amino acids. The reported effects might be of clinical importance in the treatment of mental depression and other diseases where amino acids are used as therapeutic agents.