Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous therapeutic studies on the prevention of selective vulnerability of neurons in the hippocampus have suggested that the critical period for induction of delayed neuronal injury occurs early during recirculation. To determine the onset and duration of this period, an ultrashort-acting barbiturate (methohexital) was infused into the left carotid artery of 47 gerbils after various times of recirculation following 10 minutes of bilateral forebrain ischemia. Neuronal density in the left CA1 sector was determined 7 days later by counting the number of surviving neurons per millimeter of pyramidal cell layer. In 16 saline-treated gerbils, less than 10% of the CA1 neurons survived the 10 minutes of ischemia. Postischemic carotid infusion of methohexital improved neuronal survival, the degree of improvement depending on the timing and duration of the methohexital infusion. When carried out during the initial 40 minutes of recirculation, methohexital infusion for 10 minutes increased the number of surviving neurons to approximately 60% of that in five sham-operated control gerbils. This increase was significant for infusions carried out between the 10th and 20th minutes (n = 6, p less than 0.05) and between the 30th and 40th minutes (n = 6, p less than 0.05) of recirculation. Methohexital infusion for 20 minutes increased neuronal survival to 95% and 73% of that in the controls when carried out between the 0th and 20th minutes (n = 5, p less than 0.005) and between the 20th and 40th minutes (n = 5, p less than 0.005) of recirculation, respectively. Protection was nonsignificant for 10- or 20-minute methohexital infusions carried out after the 40th minute of recirculation. Our results demonstrate that the pathologic processes leading to delayed neuronal injury in the CA1 sector are induced during the initial 40 minutes of recirculation and that barbiturates are able to reverse these processes only if given during this period.
 ...
PMID:Therapeutic window of CA1 neuronal damage defined by an ultrashort-acting barbiturate after brain ischemia in gerbils. 221 15

Primary neuronal cultures from chick embryo cerebral hemispheres received NaCN (cytotoxic hypoxia) for 120 min and were then allowed to recover. Methohexital (300 mumol/l) or ketamine (30 mumol/l) given either before or during the hypoxic period elevated adenosine triphosphate (ATP) content of the cultures 15 min after hypoxia. Prehypoxic administration of ketamine also preserved the structural integrity and ATP content of neurons 20 h later, while methohexital did not. Ketamine elevated ATP content as measured 20 h after hypoxia even when administered 15 min after beginning of recovery. Pharmacokinetic reasons for contradictory effects of ketamine on neuronal cell loss in vivo ischemia studies and our in vitro experiments are discussed.
 ...
PMID:Effects of delayed administration of methohexital and ketamine on posthypoxic cell damage of primary neuronal cultures. 233 21

Several authors suggest an influence of piracetam on brain energy metabolism. Therefore, we examined the effect of this drug on the levels of high-energy phosphates, glucose, some metabolites of glycolysis and free amino acids in the rat brain under normoxic, ischemic and postischemic conditions. In order to eliminate peripheral effects on the cerebral metabolism the isolated perfused rat brain was used as a model for this study. Methohexital was also administered for demonstrating protective effects on energy metabolism under the experimental conditions employed. The barbiturate, not piracetam, reduced the recovery time of the EEG after 1.5 or 2 min of ischemia. The depletion of energy reserves after the ischemic periods was diminished by methohexital but not by piracetam. The substrate and metabolite levels removed faster to the control levels under methohexital in the postischemic period whereas the piracetam treated brains did not differ from the controls. The subchronical treatment of rats in vivo with piracetam only caused a slightly smaller increase in the cerebral lactate concentration after anoxic periods. These results do not suggest an acute effect of piracetam on rat brain energy metabolism whereas the barbiturate methohexital may protect the brain against ischemic damage in a certain extent.
 ...
PMID:[Comparison of the effects of piracetam and methohexital on cerebral energy metabolism]. 653 5

The purpose of the present investigation was to study the effect of alpha-(+/-)-5-allyl-1-methyl-5-(1-methyl-2-pentinyl) barbituric acid (methohexital, Brevimytal sodium) on brain energy metabolism. The model of the isolated perfused rat brain was used. The high-energy phosphates, some substrates of glycolysis and the intracellular distribution of hexokinase activity were measured in the cortical tissue of the isolated rat brain after 30 min of perfusion, after ischemia or anoxia and after various recovery periods. The EEG was recorded as a parameter of the neuronal activity. The following results were obtained: 1. Ischemia and anoxia accelerated the glycolysis rate which was inhibited by methohexital. 2. The energy metabolism was more rapidly normalized after ischemia or anoxia when methohexital was added to the perfusion medium (0.2 mmol/l). 3. Compared to the corresponding preparation, the spontaneous electrical activity of the isolated brain was maintained in ischemia or anoxia for a longer period and appeared again more rapidly in the recovery periods when methohexital was present. 4. Phosphofructokinase activity was inhibited by methohexital in the recovery period after ischemia or anoxia, respectively. 5. Inhibition of hexokinase activity predominated in the surgical stage of anesthesia when glycolysis rate was not accelerated. Methohexital seemed to inhibit hexokinase activity by solubilizing the mitochondrial bound form.
 ...
PMID:[Mechanisms of the protective effect of methohexital on cerebral energy metabolism]. 720 67