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Biomedical subjects

A Gorini

Publications and source records attributed to A Gorini.

64 records · Page 4Linked to original sources
PubMed1983

Recovery after hypoglycemic brain injury. Action of some biological substances on the cerebral metabolism.

In artificially ventilated beagle dogs a severe hypoglycemic condition was induced by insulin injection, while the posthypoglycemic recovery was induced by glucose treatment at the end of a 20-min period of spontaneous electroencephalographic silence. The motor area of the cerebral cortex was analyzed for glycolytic metabolites, related amino acids, energy mediators, fatty acids, phospholipids and free fatty acids. The effects on the posthypoglycemic recovery of a intracarotid infusion with some agents (i.e. uridine, cytidine, DL-carnitine, DL-acetylcarnitine, papaverine) were tested. Severe hypoglycemia induced an extensive derangement of the brain metabolism, with partial restitution during the posthypoglycemic recovery. During this condition, the intracarotid perfusion with some biological pyrimidines (uridine, cytidine) interfered with the glycolytic and amino acid metabolites, inducing a decrease in glucose, pyruvate and lactate contents, and an increase in succinate, alanine and glutamine cerebral concns. The lipid carriers (DL-carnitine, DL-acetylcarnitine) interfered with the fatty acid degradation inducing a magnification of the decrease in the individual (palmitic acid, oleic acid) and total fatty acids, the vasodilating agent (papaverine) being practically inactive.

Acetylcarnitine↗
PubMed1983

Rat cortex synaptic and nonsynaptic mitochondria: enzymatic characterization and pharmacological effects of naftidrofuryl.

In order to investigate the in vivo pharmacological effects of the drug naftidrofuryl, we prepared populations of synaptic and nonsynaptic mitochondria from rat brain cortex. In these different mitochondrial populations the activities of citrate synthase, malate dehydrogenase, total NADH cytochrome c reductase, cytochrome oxidase, and glutamate dehydrogenase were evaluated. Except for glutamate dehydrogenase, the specific activities of the enzymes evaluated in the "free" mitochondrial fraction were higher than those observed in the "synaptic" SM1 and SM2 mitochondrial fractions, the difference between SM1 and SM2 fractions being significant. The in vivo administration of naftidrofuryl induced few and different changes in the various mitochondrial populations.

Animals↗
PubMed1983

Synaptic and non-synaptic mitochondria from rat cerebral cortex. Characterization and effect of pharmacological treatment on some enzyme activities related to energy transduction.

By a cellular subfractionation technique, synaptic and non-synaptic mitochondria from a single rat cerebral cortex were obtained. In these different mitochondrial populations the activity of citrate synthase, malate dehydrogenase, total NADH-cytochrome c reductase, cytochrome oxidase and glutamate dehydrogenase were evaluated. Except for glutamate dehydrogenase, the enzyme specific activities evaluated in the "free" mitochondrial fraction were higher than those evaluated in the "synaptic" SM1 and SM2 mitochondrial fractions, the differences between SM1 and SM2 fractions being significant. The effect of the in vivo administration of naftidrofuryl given at different doses and at different times was studied. The treatment induced few but different changes in the various mitochondrial populations.

Animals↗
PubMed1980

Acetylcholine esterase sensitivity to chronic administration of diphenylhydantoin and effects on cerebral enzymatic activities related to energy metabolism.

The effect of chronic treatment (8 months) with diphenylhydantoin (DPH) on rat brain was studied. The activity of some enzymes related to energy transduction (lactate dehydrogenase, citrate synthase, and malate dehydrogenase; NADH-cytochrome c reductase and cytochrome oxidase) and neurotransmission (acetylcholine esterase) was evaluated both in the whole brain homogenate and/or in the crude mitochondrial fraction. A clear-cut decrease of acetylcholine esterase activity was observed, the decrease continuing even after treatment was discontinued. Effects on energy metabolism and on lactate dehydrogenase, malate dehydrogenase, and cytochrome oxidase are discussed.

Acetylcholinesterase↗
PubMedDate not supplied

Influence of aging on the acute depletion of reduced glutathione induced by electrophilic agents.

A severe age-dependent depletion of reduced glutathione (GSH) occurs in rat forebrain at 1-3 h from intraperitoneal injection of the electrophilic agents cyclohexene-1-one and cycloheptene-1-one. Chronic pretreatment with central dopamine agonists (i.e., ergot alkaloids; particularly, dihydroergocriptine) partially counteracts the GSH depletion induced in 15-month-old forebrains by the prooxidants tested. In contrast, chronic pretreatment with a vasodilator agent (i.e., papaverine) magnifies the GSH depletion.

Aging↗
PubMedDate not supplied

Age-related changes by hypoxia and TRH analogue on synaptic ATPase activities.

Some synaptosomal energy-requiring ATPases were evaluated in the cerebral cortex from 3- and 24-month-old normoxic rats and rats submitted to either mild or severe chronic (4 weeks) intermittent normobaric hypoxia. Furthermore, 4-week treatment with saline or TRH analogue posatireline was performed. The activities of Na+,K(+)-ATPase, low- and high-affinity Ca(2+)-ATPase, and Ca2+,Mg(2+)-ATPase were assayed in synaptosomes and synaptosomal subfractions, namely synaptosomal plasma membranes and synaptic vesicles. With the exception of the high-affinity Ca(2+)-ATPase, aging induced a decrease in the ATPase activities from normoxic rats. The adaptation to chronic intermittent mild hypoxia was characterized by an increase in the activity of Mg(2+)-ATPase in 3-month-old rats, concomitant with a decrease in the activities of: a) Na+,K(+)-ATPase and high-affinity Ca(2+)-ATPase in both 3- and 24-month-old rats, and b) Ca2+,Mg(2+)-ATPase in 3-month-old ones. The TRH analogue posatireline increased the high-affinity Ca(2+)-ATPase in both 3- and 24-month-old hypoxic rats, concomitant with an increase in Mg(2+)-ATPase activity in 24-month-old ones. The adaptation to chronic intermittent severe hypoxia was characterized by a decrease in the activities of: a) Na+,K(+)-ATPase, Ca2+,Mg(2+)-ATPase and high-affinity Ca(2+)-ATPase in both 3- and 24-month-old rats, and b) low-affinity Ca(2+)-ATPase only in 24-month-old ones. The effect on Mg(2+)-ATPase activity was characterized by a decrease in the enzymatic form located in the synaptic plasma membranes, concomitant with an increase in the form located in the synaptic vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗
PubMedDate not supplied

Age-related alterations of skeletal muscle metabolism by intermittent hypoxia and TRH-analogue treatment.

The characteristics of the energy metabolism were evaluated in the gastrocnemius muscle from 3- and 24-month-old rats in normoxia or subjected to either mild or severe chronic (4 weeks) intermittent normobaric hypoxia. Furthermore, 4-week treatment with saline or the TRH-analogue posatireline was performed. The muscular concentration of the following metabolites related to the energy metabolism was evaluated: glycogen, glucose, glucose 6-phosphate, pyruvate, lactate, lactate-to-pyruvate ratio; citrate, alpha-ketoglutarate, succinate, malate; aspartate, glutamate, alanine; ammonia; ATP, ADP, AMP, creatine phosphate; energy charge potential. Furthermore the maximum rate of the following muscular enzymes was evaluated: hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase; citrate synthase, malate dehydrogenase; total NADH cytochrome c reductase; cytochrome oxidase. The age-related decrease in muscular glucose 6-phosphate, pyruvate and alanine concentrations and increase in citrate concentration were consistent with the age-related decreased hexokinase and increased citrate synthase activities. Ageing was characterized by a decrease in muscular creatine phosphate concentration, while the energy mediators and the energy charge potential were unchanged. The chronic (4 weeks) intermittent normobaric mild and severe hypoxia-induced alterations of the components in the anaerobic glycolytic pathway, tricarboxylic acid cycle and energy storage, that were magnified in the skeletal muscle from the oldest animals. The effect of the chronic treatment with the TRH-analogue posatireline suggests that the action of central nervous system-acting drugs could also be related to their direct influence on the muscular biochemical mechanisms related to the energy transduction.

Aging↗
PubMedDate not supplied

Acetylcholinesterase activity of synaptic plasma membranes during ageing: effect of L-acetylcarnitine.

A physiopathological role for acetylcholine (ACh) was hypothesized during ageing and related neurodegenerative diseases, e.g. dementia. This research was aimed to study acetylcholinesterase (AChE) activity during development and ageing of the frontal cerebral cortex of 4-, 8-, 12-, 16-, 20- and 24-month-old rats. This study was performed on synaptic plasma membranes, the specific subcellular compartment where the enzyme is located in vivo both in control animals and after in vivo acute treatment with L-acetylcarnitine. Maximum AChE activity was unaffected by age, and L-acetylcarnitine treatment increased enzyme activity in synaptic plasma membranes of 8-month-old rats. A comprehensive analysis of these results suggests: (a) the observed alterations in protein can substantially affect neurochemical data if results are presented as specific activities per unit protein; (b) energy metabolism plays the major role in the disturbed ACh metabolism during ageing and (c) the understanding of the mode of action of L-acetylcarnitine in treatment of dementia.

Acetylcarnitine↗
PubMedDate not supplied

Natural distribution and occurrence of coenzyme Q homologues.

The knowledge of coenzyme Q levels in tissues, organs, and subcellular compartments is of outstanding interest. A wide amount of data regarding coenzyme Q distribution and occurrence was collected in the last decades; nevertheless the data are often hard to compare because of the different extraction methods and different analytical techniques used. We have undertaken a systematic study for detecting the ubiquinone content in subcellular compartments, cells, and whole-tissue homogenates by a previously standardized HPLC method performed after an extraction procedure identical for all samples. It was confirmed that the major coenzyme Q homologue in rat tissues is coenzyme Q9; however, it was pointed out that all the rodents samples tested contain more than one coenzyme Q homologue. The coenzyme Q homologue distribution is tissue dependent with relatively high coenzyme Q10 content in brain mitochondria, irrespective of the rat strain used. There is no constant relationship of the coenzyme Q content in mitochondria and microsomes fractions. Most organisms tested (including other mammals, bird and fish specimens) have only coenzyme Q10, while the protozoan Tetrahymena pyriformis contains only coenzyme Q8.

Animals↗