Glutamate and γ‐Aminobutyric Acid Neurotransmitter Systems in the Acute Phase of Maple Syrup Urine Disease and Citrullinemia Encephalopathies in Newborn Calves

Abstract

Abstract: Cerebral cortex tissue was obtained at autopsy from neonatal Poll Hereford calves with clinically confirmed maple syrup urine disease (MSUD), neonatal Holstein‐Friesian calves with clinically confirmed citrullinemia, and matched controls. From this, synaptosomes were prepared for studies of neurotransmitter amino acid uptake and stimulus‐induced release, and synaptic plasma membranes were obtained for studies of associated postsynaptic receptor binding sites. As well as having abnormal brain tissue concentrations of the pathognomic plasma amino acids (markedly increased levels of the branched‐chain compounds valine, isoleucine, and leucine in MSUD; marked elevation of citrulline le..