Search PubMed⌕ Search

Biomedical subjects

C J Estler

Publications and source records attributed to C J Estler.

At least 73 records · Page 4Linked to original sources
PubMed1980

Influence of ethanol on histamine metabolism and release in the rat brain. II. Regions of the histaminergic pathway.

Following acute alcohol administration (80-160 mg/100 g body weight) histamine levels of rat brain cortex and thalamus were elevated and histidine decarboxylase activity was decreased. The effect was less pronounced after chronic alcohol treatment (15% v/v in drinking water for 4 weeks). In the striatum there was no change in the metabolic pattern of histamine. Histamine-N-methyltransferase was unaffected in either case. Depolarisation-induced release of histamine was inhibited by alcohol in the hypothalamus, thalamus and cortex. The results indicate that ethanol affects the histamine metabolism and release processes in the histaminergic pathway of the brain.

Animals↗
PubMed1980

[Effect of ethanol and toliprolol on the carbohydrate metabolism of the brain and liver].

After application of ethanol (1.5 mg/g i.v.) to mice, the content of glycogen of the liver and the brain decreased. The alterated content of the metabolites of the glucose break-down points to an augmentation of the glycolysis in the liver and a diminution of the glycolysis in the brain. By pretreatment with the beta-sympatholytic agent 1-isopropylamino-3-(3-tolyloxy)-2-propanol (toliprolol, Doberol) (50 microgram/g s.c.), the ethanol-induced break-down of glycogen was partially blocked in the liver and completely abolished in the brain. In contrast, mainly synergistic effects of ethanol and toliprolol on the glycolysis of the liver and the brain were found. From the results it is concluded that the ethanol-induced break-down of glycogen is mediated, at least in part, by catecholamines whereas the alteration of the glycolysis by ethanol is brought about by some different mechanism.

Adrenergic beta-Antagonists↗
PubMed1980

Effect of naftidrofuryl on high energy phosphates, glycogen, lactate and pyruvate in mouse hearts during asphyxia and post-asphyctic recovery.

The effect of naftidrofuryl (40 micrograms/g i.p.) on the ATP, phosphocreatine (PC), glycogen, lactate and pyruvate contents of the heart during respiratory arrest and postanoxic recovery was studied in mice. Naftidrofuryl increased he PC-content of the heart of normal mice. It did not prevent the metabolic changes brought about by 1 min anoxia but accelerated the post anoxic recovery of the depleted PC-content on account of delayed replenishment of the reduced glycogen stores. The changes in the ATP, lactate and pyruvate contents were not affected.

Adenosine Triphosphate↗
PubMed1979

Swimming capacity of mice after prolonged treatment with psychostimulants. III. Effect of fencamfamine on swimming endurance and availability of metabolic substrates.

The effect of long-term treatment with fencamfamine on swimming endurance and availability of metabolic substrates was investigated in mice. Fencamfamine (14 micrograms/g per day orally for 6 weeks) reduced maximum swimming capacity by more than 40%. This effect could not be attributed to motor incoordination or a diminution of pre-swimming levels of metabolic substrates such as liver and muscle glycogen or blood glucose and non-esterfied fatty acids. However, during swimming the hepatic and muscular glycogen stores were depleted more rapidly in the fencamfamine-treated animals. Thus it appears that fencamfamine leads more rapidly to a shortage of combustible substrates in the swimming animals.

Adipose Tissue↗
PubMed1979

Swimming capacity of mice after prolonged treatment with psychostimulants. II. Effect of methamphetamine on swimming performance and availability of metabolic substrates.

Swimming endurance and availability of metabolic substrates (blood glucose and nonesterified fatty acids [NEFA], liver and muscle glycogen, body fat) were studied in mice treated with 10 microgram/g methamphetamine/day for 6 weeks. At the end of the 6-week treatment, motor coordination of the methamphetamine-treated animals was much better than that of controls, and swimming capacity tended to increase. While swimming, mice treated with methamphetamine mobilized more glycogen from the hepatic stores and utilized glucose more effectively. Their NEFA levels in blood were higher than those of controls. There was no difference in the muscular glycogen content.

Animals↗
PubMed1979

Failure of phenoxybenzamine and pimozide to diminish changes in oxygen consumption and body temperature produced by caffeine.

The effects of a dopamine antagonist (pimozide) and an alpha-adrenergic receptor blocking agent (phenoxybenzamine) on caffeine-induced changes in oxygen consumption. body temperature, blood glucose and non-esterified fatty acids (NEFA) were studied in mice. Both drugs had no effect on the increase of the oxygen consumption produced by caffeine. The decline of the body temperature induced by caffeine was not significantly influenced by pimozide, while phenoxybenzamine accentuated the hypothermic effect of caffeine. The results indicate that alpha-adrenergic and dopamine receptors do not play an essential role in the caffeine-induced stimulation of overall metabolism and hypothermia.

Animals↗
PubMed1979

A high pressure liquid chromatographic method for the determination of tetracyclines in blood and organs of experimental animals.

A high-pressure liquid chromatographic method has been developed for the quantitative analysis of tetracyclines from biological material. Tetracyclines can be extracted from serum or organ homogenates by means of acetonitrile containing buffer. The extract is chromatographed on a reversed-phase column and the tetracyclines are monitored spectrophotometerically at 357 nm. Tetracyclines, pyrrolidinomethyl-tetracycline, 4-epitetracycline, and doxycycline are thus separated within 8 min. The lowest concentration for the intact molecule detectable are 0.2 micrograms/ml serum or blood and 0.4 micrograms/g organ. In a comparative study the new extraction procedure and the chromatographic analysis yielded the same results as a microbiological method.

Animals↗
PubMed1979

Distribution of pyrrolidinomethyl-tetracycline (rolitetracycline) and tetracycline in blood and various organs of mice measured by high pressure liquid chromatography.

By means of a newly developed high-pressure liquid chromatographic method the organ distribution of tetracycline (TC) and pyrrolidinomethyl-tetracycline (PMT) has been studied. When mice were treated with 50 mg/kg i.v. TC or PMT these antibiotics could be detected in all organs investigated (liver, kidney, heart, lung, muscle, spleen). Especially high concentrations were found in liver and kidneys, where TC and PMT could be detected up to 6 h. In animals treated with PMT part of the PMT applied decomposed slowly yielding TC, which was found together with PMT in blood and all organs.

Animals↗
PubMed1978

Swimming capacity of mice after prolonged treatment with psychostimulants. I. Effects of caffeine on swimming performance and cold stress.

A comparative study of the effects of a single dose of caffeine (50 microgram/g s.c.) and of 6-weeks treatment with 150 microgram/g p.o. caffeine/day on swimming capacity and resistance to cold exposure was performed in mice. In contrast to acute treatment, chronic treatment with caffeine greatly reduced the swimming capacity and diminished the ability of the animals to withstand cold stress. It could be shown by indirect means that the detrimental effect of the prolonged treatment with caffeine was not due to an accumulation of toxic levels of caffeine. Motor coordination was unaffected. There was no deficiency of metabolic substrates, since glycogen, and fat stores, and blood glucose, and fatty acid levels were not lower than in control animals. It is proposed that caffeine may interfere with the animals' ability to mobilize and spend metabolic substrates for energy requirements of skeletal muscle.

Animals↗
PubMed1978

Ethanol-induced alterations in histamine content and release in the rat hypothalamus.

In the rat hypothalamus, histamine content and histidine decarboxylas: activity are enhanced significantly after acute administration (80--160 mg/100g body weight) of ethanol. The effects are less pronounced after chronic treatment (15% v/v in drinking water for 4 weeks). Histamine methyltransferase is unaffected in either case. In hypothalamic slices preloaded with 3H-histamine and superfused with amine free solution the basal and K+-induced efflux of 3H-histamine are inhibited by alcohol. The inhibition of histamine release along with the increased levels of histamine may play an important role in the central effects of alcohol.

Animals↗
PubMed1978

Regional levels of histamine in rat brain after microwave irradiation: evidence for artifacts in the enzymatic--isotopic assay.

Histamine levels in the brain, measured fluorimetrically, were similar for rats killed by decapitation and microwave irradiation. However, enzymatic--isotopic assay yields 5--20 times higher value for microwave irradiation versus decapitation. Thin layer chromatography of the methylated products in the enzymatic--isotopic assay indicated the formation of artifacts following microwave irradiation. The results strongly suggest that a combination of microwave irradiation and enzymatic--isotopic assay is not suitable for histamine analysis in the rat brain.

Animals↗
PubMed1978

Lysine acetylisalicylate inhibits the protein synthesis in the rat gastric mucosa in vivo and in vitro.

Lysine acetylsalicylate (LAS), a water soluble derivative of acetylsalicylic acid and parenterally administrable analgesic, locally inhibits the incorporation of 14C protein hydrolysate into proteins of the rat isolated gastric mucosa. A similar effect on protein synthesis was observed after s.c. administration of the drug, whereas DNA and RNA synthesis were not affected. Obviously, LAS inhibits the translation step during biosynthesis of proteins. It is conceivable that this effect contributes to the potential ulcerogenic action of acetylsalicylate and that parenteral administration is not a criteria to protect the stomach from salicylate-induced side effects.

Animals↗
PubMed1977

Effect of salicylates on cyclic AMP in isolated rat gastric mucosa.

Studies on the cyclic AMP content of isolated rat gastric mucosa have been conducted with sodium salicylate and lysine-acetylsalicylate singly and combined with gastric secretagogues and their antagonists. Both salicylates at a concentration of 1.66 X 10(-2) M increased the amount of cyclic AMP. The increase of gastric mucosal cyclic AMP produced by sodium salicylate was diminished by prostaglandin E1 (10(-5) M), atropine (10(-6) M) and the H2-antihistamine metiamide (2 X 10(-4) M). Theophylline 3 X 10(-3) M), histamine (10(-3) M) and pentagastrin (10(-6) M) did not enhance the cyclic-AMP-response to salicylate or lysine-acetyl-salicylate.

Animals↗