G proteins in rat prefrontal cortex (PFC) are differentially activated as a function of oxygen status and PFC region.
This study tested the hypothesis that activation of guanine nucleotide binding (G) proteins in rat prefrontal cortex (PFC) is altered by hypoxia. G protein activation by the cholinergic agonist carbachol and the opioid agonist DAMGO was quantified using [(35)S]GTPgammaS autoradiography. G protein activation was expressed as nCi/g tissue in the PFC of 18 rats exposed for 14 consecutive days to sustained hypoxia (10% O(2)), intermittent hypoxia (10% and 21% O(2) alternating every 90 s), or room air (21% O(2)). Relative to basal levels of G protein activation, carbachol and DAMGO increased G protein activation by approximately 70% across all oxygen concentrations. Compared to the room air condition, sustained hypoxia caused a significant increase in G protein activation in frontal association (FrA) region of the PFC. Region-specific comparisons revealed that intermittent and sustained hypoxia caused greater DAMGO-stimulated G protein activation in the FrA than in the pre-limbic (PrL). The data show for the first time that hypoxia increased G protein activation in PFC. The results suggest the potential for hypoxia-induced enhancements in G protein activation to alter PFC function.
Hambrecht
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Department of Anesthesiology, University of Michigan, 7433 Medical Sciences Bldg. I, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5615, USA.
Vlisides
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Gozal
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Baghdoyan
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Lydic
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D000109:Acetylcholine / Q000378:metabolism; D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004195:Disease Models, Animal; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D002534:Hypoxia, Brain / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012891:Sleep Apnea Syndromes / Q000378:metabolism / Q000503:physiopathology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D000701:Analgesics, Opioid; D018679:Cholinergic Agonists; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D002217:Carbachol; D019204:GTP-Binding Proteins; D000109:Acetylcholine; D010100:Oxygen