title: Hypobaric Preconditioning Modifies Group I mGluRs Signaling in Brain Cortex.
abstract: The study assessed involvement of Ca(2+) signaling mediated by the metabotropic glutamate receptors mGluR1/5 in brain tolerance induced by hypoxic preconditioning. Acute slices of rat piriform cortex were tested 1 day after exposure of adult rats to mild hypobaric hypoxia for 2 h at a pressure of 480 hPa once a day for three consecutive days. We detected 44.1 ± 11.6 % suppression of in vitro anoxia-induced increases of intracellular Ca(2+) levels and a fivefold increase in Ca(2+) transients evoked by selective mGluR1/5 agonist, DHPG. Western blot analysis of cortical homogenates demonstrated a 11 ± 4 % decrease in mGluR1 immunoreactivity (IR), and in the nuclei-enriched fraction a 12 ± 3 % increase in IR of phospholipase Cβ1 (PLCβ1), which is a major mediator of mGluR1/5 signaling. Immunocytochemical analysis of the cortex revealed increase in the mGluR1/5 and PLCβ1 IR in perikarya, and a decrease in IR of the neuronal inositol trisphosphate receptors (IP3Rs). We suggest that enhanced expression of mGluR5 and PLCβ1 and potentiation of Ca(2+) signaling may represent pro-survival upregulation of Ca(2+)-dependent genomic processes, while decrease in mGluR1 and IP3R IR may be attributed to a feedback mechanism preventing excessive intracellular Ca(2+) release.
authors: Pavlov Institute of Physiology, Russian Academy of Sciences, Nab. Makarova, 6, Saint Petersburg, Russia, 199034. dsem50@rambler.ru.
authors: Dmitry G
authors: DG
authors: Semenov
authors: Pavlov Institute of Physiology, Russian Academy of Sciences, Nab. Makarova, 6, Saint Petersburg, Russia, 199034. belyakov07@gmail.com.
authors: Alexandr V
authors: AV
authors: Belyakov
authors: Pavlov Institute of Physiology, Russian Academy of Sciences, Nab. Makarova, 6, Saint Petersburg, Russia, 199034. anoxia@pavlov.infran.ru.
authors: Tatjana S
authors: TS
authors: Glushchenko
authors: Pavlov Institute of Physiology, Russian Academy of Sciences, Nab. Makarova, 6, Saint Petersburg, Russia, 199034. samoilov@pavlov.infran.ru.
authors: Mikhail O
authors: MO
authors: Samoilov
authors: Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106, Warsaw, Poland. esalinska@imdik.pan.pl.
authors: Elzbieta
authors: E
authors: Salinska
authors: Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106, Warsaw, Poland. jerzyl@imdik.pan.pl.
authors: Jerzy W
authors: JW
authors: Lazarewicz
mesh_terms: D000399:Air Pressure; D000818:Animals; D020013:Calcium Signaling / Q000235:genetics; D002540:Cerebral Cortex / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D054799:Phospholipase C beta / Q000096:biosynthesis / Q000235:genetics; D066195:Piriform Cortex / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D064529:Receptor, Metabotropic Glutamate 5 / Q000819:agonists / Q000096:biosynthesis* / Q000235:genetics; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D015854:Up-Regulation
chemical_list: C578937:Grm5 protein, rat; D053496:Inositol 1,4,5-Trisphosphate Receptors; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1; D008734:Methoxyhydroxyphenylglycol; D054799:Phospholipase C beta; C010117:3,4-dihydroxyphenylglycol
keywords: Calcium; GI mGluRs signaling; Hypobaric hypoxia; Preconditioning