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Biomedical subjects

B B Mrsulja

Publications and source records attributed to B B Mrsulja.

At least 37 records · Page 2Linked to original sources
PubMed1986

Regional metabolite profiles in early stages of global ischemia in the gerbil.

The present experiments were designed to determine the short-term regional changes in the cyclic nucleotides, certain glucose metabolites, high-energy phosphates, gamma-aminobutyric acid (GABA), glutamate, and glutamine in the gerbil brain following bilateral ligation of the common carotid arteries. The brains of the animals were microwaved at 20, 40, 60, 90, 120, and 300 sec of ischemia and the metabolites were measured in the cerebral cortex, hippocampus, and striatum. There were significant decreases in ATP, P-creatine, and glucose within the first 20 sec of ischemia in all three regions examined, whereas the increases in phosphate and lactate, as well as the loss of glycogen, were evident only after 40 sec of ischemia. The high-energy phosphates were essentially depleted (less than 15% of control values) in all three regions by 2 min of ischemia, indicating that the energy imbalance elicited by ischemia was comparable in the three regions. In contrast, the magnitude of the changes in the cyclic nucleotides was greater in the hippocampus than in the cerebral cortex or striatum. In addition, the decrease in cyclic GMP levels at 20 sec of ischemia preceded the increases in cyclic AMP observed at 40 sec in all three regions. The use of microwave irradiation to fix the gerbil brains not only provides a more accurate assessment of the time course of the metabolite changes but also permits studies on the deeper regions of the brain than is possible with freezing techniques.

Adenosine Triphosphate↗
PubMed1984

Cyclic AMP in the cerebrospinal fluid of patients with recent cerebral infarction.

The concentrations of cyclic adenosine 3',5'-monophosphate (c-AMP) and glucose were measured in cerebrospinal fluid (CSF) of 43 patients with recent cerebral infarction divided into five groups in respect to the time (up to 24 h) elapsed between cerebrovascular insult and CSF sampling. 10 of the additionally studied subjects were (control group) neurologically normal. None of the investigated subjects was under therapy at the time of CSF sampling. The levels of c-AMP and glucose in patients with cerebral infarction were found not to be related to the degree of neurological deficit but to the duration of ischemia. CSF c-AMP was elevated (p less than 0.001) for 8-12 h following the cerebrovascular insult and subsequently reached the level of controls. The CSF glucose level was elevated during the whole period of observation.

Adult↗
PubMed1984

Cerebrospinal fluid prostaglandin F2 alpha in stroke patients: no relationship to the degree of neurological deficit.

The concentration of prostaglandin F2 alpha (PGF2 alpha) was measured in cerebrospinal fluid (CSF) of 50 patients with recent stroke divided into three groups in respect to the time (up to 24 h) that expired between cerebrovascular insult and CSF sampling. 10 of the additionally studied persons were neurologically normal (control group). None of the investigated subjects were undergoing any therapy at the time of CSF sampling. The estimation of the neurological score revealed that the stroke patients suffered from acute cerebral ischemic attacks of varying severity. No relationship between the CSF PGF2 alpha and neurological status was found. Within the first 4 h after the stroke a marked increase in PGF2 alpha was found, afterwards being diminished but still enhanced in comparison to the controls.

Adult↗
PubMed1983

Insulin increases entrance of 2-deoxy-D-[3H]glucose in isolated rat brain microvessels.

Insulin in a dose of 0.5 U ml-1 in the incubation medium did not change ATP and phosphocreatine contents in the isolated rat brain microvessels, when energy production was supported by 5.5 mmol l-1 glucose. However, the entrance of non-metabolizable glucose analogue, 2-deoxy-D-[3H]glucose into the microvessel cells was strongly enhanced, almost 18-fold.

Adenosine Triphosphate↗
PubMed1981

Catecholamine turnover in rat cerebral cortex and caudate following repeated treatment with dihydroergotoxine.

The turnover rate of catecholamine in the cerebral cortex and caudate of adult Wistar rats was estimated after inhibition of synthesis by means of alpha-methyl-rho-tyrosine in animals treated with dihydroergotoxine (1 mg/kg body weight daily) for 1, 3 and 10 days. Following single as well as repeated treatments with the drug, blockade of norepinephrine receptors, as indicated by the increased catecholamine turnover rate, was found in both brain structures. The turnover rate of dopamine was changed only after repeated treatments; it was decreased in the cortex and increased in the caudate, indicating both agonistic and antagonistic effects of dihydroergotoxine on dopamine receptors.

Animals↗
PubMed1980

The effect of physostigmine on (Na+ + K+)-ATPase activity in different rat brain regions.

The activity of (Na+ + K+)-ATPase and acetylcholine esterase were followed in rat brain cerebral cortex, caudate, thalamus, hippocampus and medulla after i.v. administration of physostigmine. Both enzymes were found to be inhibited in a dose-dependent manner. The most pronounced inhibition of (Na+ + K+)-ATPase was found in caudate, where the highest activity of acetylcholine esterase is found.

Acetylcholine↗
PubMed1980

Brain capillary guanosine triphosphatase: a distinction from adenosine triphosphatase.

Differences in kinetic properties, pH response, sensitivity to ouabain, and disc-acrylamide electrophoresis resolution, are observed when GTP and ATP are used as the substrates for triphosphohydrolases in isolated rat brain microvessels. In brain parenchyma there are no such differences. It is concluded that substrate-specific GTPase exists in brain microvessels.

Adenosine Triphosphatases↗
PubMed1980

Monoamines and related enzymes in cerebral cortex and basal ganglia following transient ischemia in gerbils.

The post-ischemic effects on cerebral cortex and basal ganglia monoamine levels and monoamine oxidase (MAO A and B) and catechol-O-methyl transferase (COMT) activities were evaluated in Mongolian gerbils (Meriones unguiculatus) subjected to bilateral common carotid arteries of occlusion for 15 min and reflow for 7 days. Disorders of monoamine metabolism was found in ischemic brain which persisted during the long-term post-ischemia. A rebound increase of norepinephrine and serotonin appeared in early stages (up to 1 h) of post-ischemia both in cerebral cortex and basal ganglia; a rebound increase of dopamine as found only in cerebral cortex. Thereafter, the serotonin level ws enhanced over the control level during the whole post-ischemic period whereas the levels of catecholamines were reduced particularly in basal ganglia. With respect to monoamine content and activities of monoamine degraded enzymes an oscillatory behavior was observed in the post-ischemia. Disorder of the monoamine metabolism found during post-ischemic period possibly contributes to neurological dysfunction after an ischemic insult.

Animals↗
PubMed1980

Key enzymes of glycolysis in rat brain: effects of single and repetitive treatment with dihydroergotoxine (Redergin).

The activities of hexokinase, phosphofructokinase and lactate dehydrogenase were measured in the brain of Lewis rats that were 75 days, 6 months and 12 months old. During this period (75--360 days) the activity of hexokinase declines about 5-fold, that of lactate dehydrogenase increases 2-fold, while phosphofructokinase activity is unchanged. Dihydroergotoxine treatment (25 days, 1 mg/kg body weight daily) counteracts these changes. It is concluded that repeated treatment with dihydroergotoxine increases capacity of glycolytic pathway and decreases the capacity of pyruvate to lactate conversion, which could be otherwise excessive in senescent brains under certain pathological conditions.

Age Factors↗
PubMed1979

Brain microvessel hexokinase: kinetic properties.

Kinetic differences between brain capillary and parenchymal hexokinase in the presence of glucose, ATP. fructose, potassium, sodium and different pH were established. Parenchymal hexokinase is more susceptible to glucose inhibition, can tolerate greater variations in the ATP concentration, is inhibited by increasing concentrations of fructose and potassium, and showed greater activity on the lower pH values. The data suggest that in brain parenchyma and endothelial cells of brain microvessels, there are 2 different enzymes with regard to the kinetics properties.

Adenosine Triphosphate↗
PubMed1978

Alterations of putative neurotransmitters and enzymes during ischemia in gerbil cerebral cortex.

Bilateral occlusion of common carotid arteries in Mongolian gerbils was produced for the periods (up to 15 min) which were shown to be totally reversible. There was an initial increase of cyclic AMP and GABA levels and enhanced activities of adenylate cyclase and glutamate decarboxylase, as well as the reduction of norepinephrine level and decreased activities of monoamine oxidase, GABA-transaminase and Na+-K+-ATPase. Following these changes, decreased concentration of dopamine, serotinin and glutamate were found. The activities of total protein kinase and acetylcholinesterase were found to be reduced after longer periods of short-term ischemia. The data are consistent with the concept of increased non-controled release of putative neurotransmitters in ischemia.

Adenylyl Cyclases↗