Uptake of phenylalanine by the rat brain after resuscitation from cardiac arrest.

In 47 adult rats 10-min cardiac arrest was induced by the intrathoracic compression of the heart vessel bundle. The animals were sacrificed at 15, 30, 60, 120 min and 6 h or 1, 3, 7 days after resuscitation. Decapitation was performed 15 sec after intracarotid injection of mixture of L-[U-14C] phenylalanine (PHE) and tritiated water in PBS buffer. By the dual label method the brain uptake index (BUI) and percent of injected dose of amino acid in the cerebral hemisphere were calculated. A decrease of PHE uptake and drop of BUI revealed the blood-brain barrier (BBB) alterations resulting in diminution of amino acid transport into brain. The most pronounced changes developed between 15 and 120 min after resuscitation and also after 7 days. The above data revealed the decreased active transport of PHE in the early and late periods after ischemic insult.