Spectroscopic properties of low-spin ferrous heme complexes and hemeproteins at 77degrees K.
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Animals↗
Biomedical subjects
G C Wagner
Publications and source records attributed to G C Wagner.
Spectroscopic properties of protoheme complexes undergoing reversible oxygenation.
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Chemical Phenomena↗
Redox potentials of certain vitamins K: implications for a role in sulfite reduction by obligately anaerobic bacteria.
Redox potentials of a menaquinone (MK-6), isolated in earlier researches from two species of the obligately anaerobic genus, Desulfovibrio, as well as two other vitamins K(2)-menaquinones (MK-5) and (MK-9)- have been determined polarographically. The measurements have been validated by determination of redox potentials of 1,4-naphthoquinone and vitamin K(1) which agree with published potentiometric values. E(m7) for menaquinone (MK-6) is -0.067 +/- 0.010 V. Redox potentials calculated for terminal acceptor couples currently proposed in the mechanisms of sulfate reduction by Desulfovibrio are consistent with the involvement of menaquinone (MK-6) in at least one of the steps postulated during electron transfer with ultimate production of sulfide.
Anaerobiosis↗
Simultaneous changes in striatal dopamine, serotonin, and metabolites after withdrawal seizures in rats from dependence on alcohol.
Ethanol dependence was achieved in male, Long-Evans rats after 8 days on a balanced liquid diet that supplied 4.5% ethanol. After 1-h access to a solution of 10% ethanol (95%)/5% sucrose, the rats were deprived of food, water, and ethanol for 9 h. Following 30-s key jingling, about 80% of the animals exposed to ethanol experienced tonic-clonic seizures. Neurochemical analyses of striatal tissues revealed a significant (p < 0.05) increase in dopamine (DA) and a significant decrease in serotonin (5-HT) in the ethanol-exposed rats that had seizures compared to control rats. Homovanillic acid concentrations of the ethanol-treated rats with seizures were significantly higher than the levels found in ethanol-treated animals that had experienced no seizures. Daily average ethanol intake of the rats that had seizures vs. those that did not was almost the same at 16 g/kg/day. The findings indicate that rats experiencing ethanol withdrawal-induced seizures manifest opposite alterations in dopaminergic and serotoninergic activity compared to controls. The present results do not reveal if the striatal changes are caused by ethanol rather than by the seizures.
Acoustic Stimulation↗
Diet composition, alcohol utilization, and dependence.
Experiments were carried out in which a nutritionally balanced liquid diet previously used in this laboratory was modified as to total calorie content and high or low carbohydrate and fat concentration. Ethanol was added at 4.5% and 6.2% of diet weight and provided either 27% or 34-37% of total calories depending upon the changes in nutrient content. Measurements included 8-day food/calorie and ethanol consumption, plasma ethanol level, liver alcohol dehydrogenase (ADH) activity, and rate of audiogenic-induced withdrawal seizures. The original liquid diet with 4.5% ethanol was consumed in significantly lesser amounts than the alcohol-free diet, and essentially no body weight gain occurred, regardless if the major nonalcohol, nonprotein calorie source was fat or carbohydrate. When the calorie content of the diet was boosted through the addition of extra carbohydrate or fat (at the expense of water), appreciable weight gain was noted; in the case of the higher calorie diet boosted with more carbohydrate (maltodextrin) calories, growth was similar to that observed on the alcohol-free control diet. On this latter diet ethanol calories appeared to be utilized close to their theoretical value of 7 kcal/g. Blood alcohol levels were significantly higher on the lower calorie diets and were lowest on the high-calorie, high-carbohydrate, 4.5% ethanol diet. This diet also allowed for the lowest rate of withdrawal seizures despite an ethanol intake that was as high as on the lower calorie diets. Essentially, no differences were noted among ADH activities for the dietary treatments studied and thus, did not explain the differences observed among blood ethanol levels. When the alcohol concentration in the high-carbohydrate, high-calorie diet was raised to 6.2% from 4.5% to provide 34% of total calories, the rats responded by decreasing their food (and alcohol) intake to the same level as did the animals receiving a much lower calorie diet, but with 37% of caloric alcohol content. This suggests that at a diet alcohol concentration of 34-37%, one or more nutrient metabolites become limiting in the utilization of ethanol, resulting in food intake adjustments that maintain similar amounts of alcohol consumption.
Alcohol Drinking↗
Amphetamine and fenfluramine suppress ethanol intake in ethanol-dependent rats.
Alcohol intake or preference for alcohol has been attributed to concomitant dopamine and serotonin dysfunction in rats. Amphetamine and fenfluramine, administered alone, have been shown to reduce food and fluid intake as well as alcohol consumption while acute coadministration of these agents has been shown to suppress audiogenic seizure in rats withdrawn from alcohol. The present study was designed to assess the effectiveness of chronic amphetamine and fenfluramine coadministration on reducing alcohol intake. Chronic coadministration of amphetamine (2 mg/kg) and fenfluramine (8 mg/kg) reduced alcohol consumption during choice trials in both alcohol-dependent and alcohol-nondependent rats while not affecting water intake. The findings indicate that coadministration of amphetamine and fenfluramine, a treatment effective in reducing alcohol withdrawal seizures, also selectively attenuates alcohol consumption.
Alcohol Drinking↗
Alcohol utilization and dependence with special reference to protein level in a liquid diet for rats.
Experiments were carried out with a nutritionally balanced diet to test the response of rats to levels of ethanol between 0% and 6%, and to different levels and sources of protein and amino acid supplements in relation to alcohol utilization and withdrawal seizures. The high-calorie/high-carbohydrate liquid diet was well tolerated when the alcohol level was less than 30% of total calories, or 4.5% of diet. When alcohol was provided at 6% of diet, or 33% of total calories, growth and withdrawal seizure rates were negatively affected in comparison with the lower ethanol levels, even though ethanol consumption (in g/kg/day) was not different. The 6% alcohol diet was then altered through the addition of more protein calories, from 13% to 20%. This supplementation improved growth rate of the animals and reduced the rate of withdrawal seizures. The improvement from the additional protein was observed with both casein and soy protein, and was not attributable to any one or even several amino acids that might serve as transmitter precursors. A mixture of all essential amino acids representing the difference in amino acids between 13% and 20% casein protein calories was an effective as the equivalent amount of intact protein. The nonessential amino acids equivalent to 7% casein protein calories, when added to the 13% protein calories diet, increased the rate of withdrawal seizures, presumably by exacerbating the protein deficiency in the 13% protein diet. It was concluded that a 1000-1200 kcal/kg diet with 20% kcal from protein and 50% kcal from carbohydrate provides an optimal nutrient balance for efficient utilization of a 6% ethanol liquid diet for rats.
Alcoholism↗