INVESTIGATION OF BLOOD-BRAIN-BARRIER PENETRATION AND CENTRAL-NERVOUS-SYSTEM DISTRIBUTION OF PEPTIDES AND PROTEINS BY IN-VIVO AUTORADIOGRAPHY

The delivery of peptides and proteins to the brain holds great therape utic promise. Several mechanisms of penetration across the blood-brain barrier, including passive diffusion and specific transport, have bee n identified and characterized. An important aspect of this occurrence concerns the anatomical fate of blood derived peptides and proteins w ithin the brain after they enter the central nervous system. In vivo f ilm autoradiography and computer assisted image analysis represent ear ly attempts to identify these target sites. This article reviews recen t investigations in which in vivo autoradiography has helped to determ ine specific regions of accumulation of peptides and proteins within t he brain after both peripheral and central administration.