Hypoxia-induced responses

A high extracellular sodium concentration ([Na" ],) attenuated the hypoxia-induced response in the CAl pyramidal cell layer of rat hippocampal slices, its onset latency was longer and the time constant of its decay phase was shorter than in controls (Yamaguchi etal. 1997). In contrast, hypoxia in low [Na ]o elicited a significantly enhanced response with a short onset-latency and delayed decay phase. This exaggerated response to hypoxia in low [Na ]o was reversed by pre-incubation of the shce in low [Na ] prior to the hypoxic insult. 

Appheation of DA to the isolated PG in vitro has no direct effect on the activity recorded from both the CSN and the GPB (19,31). Similarly, DA receptor blockade in cocultures of rat carotid body cells and PG neurons affects neither the basal activity of spontaneously active neurons nor the hypoxia-induced responses (23). However, when DA is applied prior to ACh it produces a dose-related modification of the responses induced by the latter. Thus, for a given ACh dose, the lowest DA dose potentiates the response, while the largest dose inhibits the response (19,31). The inhibitory effect of DA on ACh-induced responses is partly reversed by the D2 receptor antagonist spiperone (31). The presence of dopaminergic nemons (32) as well as mRNA for D2 receptors (33) has been shown in a population of PG neurons. These data suggest that DA may act as a modulator of afferent activity in the terminals of PG neurons, and if released at this terminal, it could modulate both the receptor cell and the terminal. 

TF transcription factor, R receptor, Fur ferric uptake regulation protein, NF-kB nuclear factor-kB, AP-1 activator protein-1, Egr-1 early growth response-1, VDR la,25-dihydroxy-vitamin D3 receptor, RXR retinoid X receptor, PPARy peroxisome proliferator-activated receptor y NFAT nuclear factor of activated T-cells, HSF heat shock factor, p53 tumor suppressor p53, HIF-1 hypoxia inducible factor-1. ... 

Delagarza VW. (1998). New drugs for Alzheimer s disease. Am Fam Physician. 58(5) 1175-82. DeNoble VJ, Repetti SJ, Geipke LW, Wood LM, Keim KL. (1986). Vinpocetine nootropic effects on scopolamine-induced and hypoxia-induced retrieval deficits of a step-through passive avoidance response in rats. Pharmacol Biochem Behav. 24(4) 1123-28. 

Diabetes is hypothesized to cause cardiac protein acetylation and the acetylation alters the protein function (Fig. 3b). Hypoxia-inducible factor-1 (HIFl) is a transcription factor found in mammalian cells cultured under reduced oxygen tension that plays an essential role in cellular and systemic homeostatic responses to hypoxia. Diabetes interferes with cellular response to hypoxia. In hyperglycemic conditions HIFl degradation is increased because of enhanced HIFl acetylation by... 

Recent studies have demonstrated that overexpression of HDACl represses the tumor suppressors, p53 and von Hippel-Lindau (VHL), but induces the hypoxia-responsive genes, hypoxia inducible factor alpha (HIF-la) and vascular endothelial growth factor (VEGF) and increases angiogenesis. Conversely, HDAC inhibitors derepress the tumor suppressors, p53 and VHL, and repress HIF-la and VEGF [68, 69]. 

Benita Y, Kikuchi H, Smith AD et al (2009) An integrative genomics approach identifies hypoxia inducible factor-1 (HIF-1 )-target genes that form the core response to hypoxia. Nucleic Acids Res 37 4587-4602... 

Responses to low oxygen tension in tissues (hypoxia) are important to all aerobic organisms.464/467a d In mammals transcription of hypoxia-responsive genes is regulated by hypoxia inducible factors HIF-1 and... 

Hypoxia creates conditions that, on one hand, are conducive to the accumulation of extracellular adenosine and, on the other hand, stabilize hypoxia-inducible factors, such as HIF-1 a (Linden 2001 Sitkovsky et al. 2004 Fredholm 2003 Hockel and Vaupel 2001 Minchenko et al. 2002 Semenza 2000). HIF-1, the most important factor involved in the cellular response to hypoxia, has been extensively studied this last decade. However, despite the substantial number of investigations into HIF-1, many secrets about its function remain to be revealed. 

Chi, N.C., and Karliner, J.S. 2004. Molecular determinants of responses to myocardial ischaemia-reperfusion injury focus on hypoxia-inducible and heat shock factors. Cardiovasc. Res. 61 437-447. 

Firth, J.D., B.L. Ebert, and P.J. Ratcliffe (1995). Hypoxic regulatin of LDH A interaction betwee hypoxia inducible factor 1 and cAMP response elements. J. Biol. Chem. 270 21021-21027. 

Semenza, G.L., B. Jiang, S.W. Leung, R. Passantino, J. Concordet, P. Maire, and A. Giallongo (1996). Hypoxia response elements in the aldolase A, eno-lase 1, and lactate dehydrogenase A gene promoters contain essential binding sites for hypoxia Inducible Factor-1. J. Biol. Chem. 271 32529-32537. 

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