title: Different effects of hypothermia on amino acid incorporation and on amino acid uptake in the brain in vivo.
abstract: The temperature dependence of the incorporation of amino acids into cerebral proteins and that of the transport of amino acids through the blood-brain barrier were studied. We measured the protein synthesis rate in vivo over a wide temperature range (14 degrees C-38 degrees C) in male Sprague-Dawley rats using a flooding dose of labeled valine. There was a linear dependence of the protein synthesis rate on temperature. The temperature quotient expressed as per cent decrease per 1 degree C was somewhat lower at the lower temperatures, a decrease from 7.8% in the 37.7-32.5 degrees C range to 6.7% in the 25.5-14 degrees C range. The transport of the three amino acids phenylalanine, lysine, and alanine, representing three transport systems, through the blood-brain barrier showed no temperature dependence in vivo. The results show that in hypothermia cerebral metabolic rates are lowered to a great extent, while some aspects of metabolic transport are not affected.
authors.affiliation: Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York 10962.
authors.forename: J F
authors.initials: JF
authors.lastname: Sayegh
authors.forename: H
authors.initials: H
authors.lastname: Sershen
authors.forename: A
authors.initials: A
authors.lastname: Lajtha
mesh_terms: D000409:Alanine / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D001831:Body Temperature; D001921:Brain / Q000378:metabolism*; D007036:Hypothermia, Induced; D008239:Lysine / Q000378:metabolism; D008297:Male; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D014633:Valine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010649:Phenylalanine; D014633:Valine; D008239:Lysine; D000409:Alanine