Previous studies have shown that oscillations of the metabolism can occur in cardiomyocytes under conditions simulating ischemia/reperfusion. It is not known whether they can also occur during real ischemia with near-anoxic oxygen tension. Here, using oxygen clamp in on-chip picochambers, we exposed single resting cardiomyocytes to near anoxia (pO(2) < 0.1 mm Hg). We show that at near anoxia, t...

Freshwater turtles as a group are more resistant to anoxia than other vertebrates, but some species, such as painted turtles, for reasons not fully understood, can remain anoxic at winter temperatures far longer than others. Because buffering of lactic acid by the shell of the painted turtle is crucial to its long-term anoxic survival, we have tested the hypothesis that previously described dif...

The overall goal of this study was to determine the molecular and metabolic responses of chemostat cultures of model nitrifying bacteria to imposition of and recovery from transient anoxic conditions. Based on the study, a specific directionality in nitrous oxide (N(2)O) and nitric oxide (NO) production was demonstrated. N(2)O production was only observed during recovery to aerobic conditions a...

This study examined the metabolic response of Drosophila melanogaster exposed to O(2) concentrations ranging from 0 to 21% and at 100%. The metabolic rate of flies exposed to graded hypoxia remained nearly constant as O(2) tensions were reduced from normoxia to approximately 3 kPa. There was a rapid, approximately linear reduction in fly metabolic rate at P(O(2))s between 3 and 0.5 kPa. The red...

The effects of anoxia were studied in freshly isolated rat hepatocytes maintained in agarose gel threads and perfused with Krebs-Henseleit bicarbonate buffer (KHB). Cytosolic free calcium (Ca2+i) was measured with aequorin, intracellular sodium (Na+i) with SBFI, intracellular pH (pHi) with BCECF, lactic dehydrogenase (LDH) by the increase in NADH absorbance during lactate oxidation to pyruvate,...

BACKGROUND The wood frog, Rana sylvatica, tolerates freezing as a means of winter survival. Freezing is considered to be an ischemic/anoxic event in which oxygen delivery is significantly impaired. In addition, cellular dehydration occurs during freezing because water is lost to extracellular compartments in order to promote freezing. In order to prevent severe cell shrinkage and cell death, it...

Rhizomes of Acorus calamus L. were able to maintain a functional alpha-amylase under anoxia, whereas a steep decrease in the enzyme protein content and activity took place in potato tubers. The stress-induced control in tubers occurred on the translational level. It is suggested that this decrease is one of the key factors with regard to anoxia intolerance.

During normoxia, glutamate and the glutamate family of ion channels play a key role in mediating rapid excitatory synaptic transmission in the central nervous system. However, during hypoxia, intracellular [Ca2+] increases to neurotoxic levels, mediated largely by the N-methyl-D-aspartate (NMDA) subfamily of glutamate receptors. Adenosine has been shown to decrease the magnitude of the hypoxia-...

1. The role of glutamate in producing tissue damage during cerebral anoxia was investigated in brain slices using antagonists to the NMDA and AMPA receptor types. 2. Tissue function was assessed by field recordings of the synaptically evoked potentials elicited by stimulating the main afferent input to the olfactory cortex, the lateral olfactory tract. Anoxia was produced by bathing the slice i...

Sensory neurons can detect ischemia and transmit pain from various organs. Whereas the primary stimulus in ischemia is assumed to be acidosis, little is known about how the inevitable metabolic challenge influences neuron function. In this study we have investigated the effects of anoxia, aglycemia, and acidosis upon intracellular Mg(2+) concentration [Mg(2+)](i) and intracellular pH (pH(i)) in...