摘要:

Abstract:The fate of tritium labelled methylatropine was investigated in newborn, 3 and 6 weeks and 3 months old dogs and compared with data for adult dogs. After intravenous injection the half‐life of plasma radioactivity was 165‐225 minutes in the three oldest groups. After subcutaneous injection the corresponding figure was 110‐155 min. and there were no consistent differences in the plasma half‐lives and concentrations between the different age groups. The urinary excretion of radioactivity in four hrs was the same after subcutaneous and intravenous injection and varied between 40 and 70 per cent of the injected amount independantly of the age of the dog. The fraction of unchanged drug in the urine collected between 2‐4 hrs after injection was 50‐100 per cent and there were no significant age differences in the fraction or pattern of metabolites. At 2 and 4 hrs after injection the concentration of radioactivity in the liver, and kidney in the newborn dog was about half of that of the adult and 6 weeks old dogs respectively, while the bile concentrations were 3‐15 times higher in the older dogs than in the newborn. The brain and cerebrospinal fluid concentrations at 2 and 4 hrs after injection were not significantly different between the newborn, 6 weeks old and

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01523.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Two simple arrangements are described by means of which the Pco2and Po2of physiological salt solutions placed in open vessels can easily be adjusted and maintained at known and constant levels during biological experiments on immersed living tissue. The characteristic feature of the proposed arrangements is that a certain fraction of the area of the free surface of the fluid, under standardized stirring conditions, is exposed to an atmosphere with known and constant concentrations of CO2and O2. The constancy of the Pco2and the Po2in the fluid is practically uninfluenced by the additional stirring caused by the biological experiments for which the bath is used.

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01524.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:The rotacone is a modified rotarod found suitable for the measurement of drug‐induced changes in motor coordination. On this apparatus mice are forced to walk against increasing surface speed until they drop off the cone. As the test is quick the animals are not exhausted, and there is no problem with mice taking “free rides”. Saline‐treated mice showed a constant performance level in 4 immediately successive trials, whereas animals under the influence of drugs, especially chlordiazepoxide, showed an increase in performance in the 4 trials. After chlorpromazine, meprobamate and chlordiazepoxide there is a graded response with a normal distribution of scores. Pentobarbital gave a response of the all or n

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01525.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:A single pretreatment with chlordiazepoxide, HCl (50 or 165 mg/kg) to male mice produced tolerance to the compound 24 hours later as measured by the performance on a modified rotarod (the rotacone). The plasma levels of chlordiazepoxide and the major metabolites 7‐chloro‐2‐amino‐5‐phenyl‐3H‐1,4‐benzodiazepine‐4‐oxide (D‐M) and 7‐chloro‐1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzo‐diazepine2‐one‐4‐oxide (“lactam”) were determined in mice acutely and repeatedly treated with chlordiazepoxide. Although a single pretreatment of chlordiazepoxide, HCl increases the rate of metabolism other factors must be involved to explain the tolerance developed. Mice treated twice with chlordiazepoxide, HCl 165 mg/kg had significantly higher plasma levels of the compound and its metabolites 10 and 30 minutes after the second injection (given 24 hours after the first injection) as compared with mice receiving 50 mglkg chlordiazepoxide, HCl acutely, while the performance on the rotacone was similar in the two groups. Chlordiazepoxide had the most potent effect in the rota

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01526.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:A decrease of the experimental temperature from 25° to 12° resulted in a 10.2 × increase in the sensitivity of the toad's heart to the positive chronotropic effect of adrenaline, measured as ED50 ratios, and in a 4.9 × increase of the sensitivity to the α‐adrenergic drug, phenylephrine. In contrast, the sensitivity to the β‐adrenergic drug, isoprenaline, did not change significantly with temperature alteration. Acclimatization of the animals to 25° increased the sensitivity of the heart to adrenaline by 2.2 × compared wih the 10° maintained toads. The blocking capacity of the β‐adrenergic blocking agent, propranolol, was decreased with cold. The most pronounced decrease was seen in the blocking capacity to the effect of isoprenaline. On the other hand, the blocking capacity of the α‐adrenergic blocking agent, phenoxybenzamine, was decreased with warmth. In this case the most marked decrease was observable during antagonism between phenoxybenzamine

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01527.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:The relative amount of methyl mercuric compounds in rat bile is not dose dependent for doses from 1 mg Hg/kg rat weight to less than 1 μg Hg/kg given as methyl mercuric chloride. Binding of mercury in the bile and reabsorption from the intestinal tract are similar for doses several orders of magnitude apart. The reabsorption of mercury is not part of an enterohepatic circulation, as mercury which is reabsorbed is not predominantly reexcreted. The distribution of sulfhydryl groups between the liver and the bile does not explain the distribution of mercury. The excretion of mercury does not increase when the volume of bile increases. The mercury concentration in the bile reflects the liver concentration and not the plasma concentration. There have been no indications of an active transport mechanism for methyl mercuric compounds from the liver cell to the bile demonstrated

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01528.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:The uptake of3H‐piribenzil (2‐hydroxymethyl)‐1,1‐dimethylpiperidinium (‐3H) benzilate, an anticholinergic agent, into rat liver slices was found to be concentration and time dependent. At a medium concentration of 10−5M the slice to medium (S/M) ratio was about 4 after 60 minutes incubation. The uptake was decreased by metabolic inhibitors (iodoacetic acid and 2,4‐dinitrophenol) and by incubation in N2‐atmosphere. Structurally similar compounds (cations) also decreased the uptake of piribenzil but organic anions did not influence the uptake process. Chromatographic studies revealed unchanged piribenzil in the slices. Binding of piribenzil to liver homogenate occurred. Moreover efflux of piribenzil from liver slices was decreased by iodoacetic acid. Thesein vitroexperiments may reflect processes responsible for the biliary excretion of

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01529.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Canine subcutaneous adipose tissue was isolated and auto‐perfusedin situ. Nicotinic acid (NicA) (4 or 40 mg/kg intravenously caused an increased lactate release and/or a decreased pyruvate release from the tissue. Following the administration of the higher dose of NicA the glucose uptake was also enhanced. While there was no inhibition of basal lipolysis, basal FFA release was significantly reduced following the higher dose of NicA. Lipolysis induced by sympathetic nerve stimulation (4 Hz for 10 min.) was inhibited by 60‐80 per cent, while induced FFA release was inhibited by 90 per cent or more. This increase in re‐esterification was statistically significant. It is concluded that re‐esterification plays an important role in the FFA‐lowering effec

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01530.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Urine and faeces of rats were investigated for phenolic compounds after oral administration of14C‐L‐DOPA.Germ‐freeandconventionalrats were used. The urinary radioactive metabolites detected were: 3‐methoxy‐4‐hydroxyphenylethylamine, 3‐methoxy‐4‐hydroxyphenylacetic acid,m‐hydroxyphenylacetic acid, andm‐hydroxyphenylpropionic acid.Conventionalrats excreted more radioactivemeta‐compounds than thegerm‐freerats. The faeces ofgerm‐freerats contained predominately radioactive 3‐methoxy‐4‐hydroxy‐phenylacetic acid, and faeces of theconventionalrats contained predomina

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01531.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01532.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY