BLOOD-BRAIN-BARRIER TRANSPORT UNDER DIFFERENT PHYSIOLOGICAL AND PATHOPHYSIOLOGICAL CIRCUMSTANCES INCLUDING ISCHEMIA

The blood-brain barrier (BBB) transport of amino acids, glucose and choline was studied under different experimental conditions. The influence of the neuropeptide arginine-vasopressin (AVP) on the transport of leucine and phenylalanine was investigated after peripheral and central nervous application of the peptide and in rats with different endogenous levels of the hormone. AVP elicited changes of the kinetics of the neutral amino acid transport across the BBB accompanied by a decrease of the permeability/surface area (P(a)S)-product. Also the influence of different nootropic drugs on the BBB transport was investigated under various circumstances of impaired brain function, i.e. after treatment with scopolamine or ethanol and after unilateral carotid artery occlusion. Changes of the kinetics of leucine transport and of the P(a)S-product of leucine, choline and glucose were found. The results are discussed as part of complex actions of the peptides and nootropics including alterations of the cerebral hemodynamics and brain metabolism.