摘要:

Abstract:The effects of verapamil and propranolol on contractility, frequency, coronary flow and myocardial oxygen consumption were compared in isolated rabbit hearts, which were retrogradely perfused in a re‐circulatory system. Cumulative concentrations of verapamil ranging from 0.01–0.2 μg/ml had a progressive coronary vasodilatatory effect accompanied by a very pronounced inhibition of contractility and a reduction in cardiac efficiency. Heart rate was not significantly changed. Propranolol produced a decrease in coronary flow, but lower concentrations from 0.05 up to about 1 μg/ml caused an improvement in cardiac efficiency and a less pronounced inhibition of contractility. A negative chronotropic effect was observed. Both agents caused an increase in the ratio of coronary venous oxygen content to myocardial oxygen consum

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03492.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Organic solvents such as chloroform, acetone, ethyl ether or n‐hexane, are all able to enhance the measurable UDP‐glucuronosyltransferase activity when addedin vitroto the microsomal suspension. The aliphatic alcohols, methanol, ethanol, or butanol were, however, unable to activate the microsomal enzyme but caused instead an inhibition of the UDP‐glucuronosyltransferase. The inhibitory action increased with the length of the alkyl

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03493.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Theophylline is able to decrease the thresholds of nociceptive stimulation (motor response, vocalisation and vocalisation afterdischarge), the effects being maximal at 30 minutes after administration. At this time theophylline was found to increase the endogenous level of dopamine in the telencephalic cortex and decrease the level of noradrenaline in regions including the diencephalon and the striatum. After inhibition of tyrosine hydroxylase with α‐methyl‐p‐tyrosine, theophylline was found to decrease the depletion of dopamine brought about by the inhibitor in the telencephalic cortex, indicating a decreased turnover of dopamine in this region. Theophylline was able to accelerate the decrease in noradrenaline concentration in the diencephalon‐striatum region induced by the enzyme inhibition, indicating an increased turnover of nordarenaline. The 5‐HIAA content in the telencephalic cortex was found to be decreased by theophylline and increased in the mesencephalon‐pons‐medulla oblongata region. After pre‐treatment with probenecid the latter increase was more pronounced while the decrease in the cortical structures was abolished by the pretreatment. It was furthermore found that probenecidper sewas able to increase the thresholds for nociceptive stimulation and was able to counteract the effect of theophylline on these thresholds, and inpreliminaryexperiments probenecid was found to affect the brain concentrations of noradrenaline. Inhibition of tyrosine hydroxylase was also found to counteract the decrease in the threshold of vocalisation afterdischarge produced by theophylline. From the experiments it seems possible that there is a relationship between a reduced turnover of dopamine and serotonin in the telencephalic cortex and the theophylline‐induced decrease of the threshold for vocalisation afterdischarge (affective component of the pain reactions) while the modulation of the vocalisation response may be related to the serotonin metabolism in lower bra

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03494.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:The water movement between plasma and the vitreous body in eyes from guenon monkeys and rabbits was measured under physiological conditions and compared to theoretically calculated values for free water diffusion in a sphere of the same order of magnitude. The results show that a steady‐state is obtained between plasma and the vitreous body after 90 minutes of constant plasma concentration in monkeys as well as in rabbits. In contrast to this, the theoretical calculations show that a steady‐state is not established within 180 minutes if only simple diffusion takes pl

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03495.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:Isolated left rat atria were stimulated at a frequency of 180 per min. An increase in the strength of electrical stimulation from threshold (11±2mA) to suprathreshold values (50 mA) caused an initial decrease followed by an increase in the amplitude of the contractions. On the basis of experiments with an adrenergic β‐receptor blocker, practolol 5±10−6M, and atropine 1.43 ± 10−6M, it was shown that suprathreshold stimulation released noradrenaline as well as acetylcholine (ACh) within the myocardium. The effect of phenoxybenzamine, an adrenergic α‐receptor blocker with an atropine‐like activity, was also tested. At threshold stimulation this drug (2.5±10−6M) caused no changes in contractile force, while at suprathreshold values a pronounced increase in the amplitude of the contractions was observed. This effect was probably, at least partly, due to a blockade of the ACh‐induced depression of atrial contractile force. It is concluded that the interpretation of drug effects on isolated atrial preparations depends on the design of the experiments such as the strength of the ele

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03496.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:The analgesic effect of immobilon® (etorphine 125 μg/ml and acepromazine 500 μg/ml) has been compared with that of its two components and of morphine. The following values were found (ED 50 μg/kg subcutaneously; acetic acid test, mice): immobilon (etorphine 0.3 + acepromazine 1.2); etorphine 1.2; acepromazine 40 and morphine 350. The action of immobilon and of the antagonist, diprenorphine (revivon®) on systolic/diastolic blood pressure, heart rate, ECG, respiration and rectal temperature was checked during clinical neuroleptanalgesia in seven dogs. No effect on the systolic and a slight fall in the diastolic blood pressure were observed. Furthermore a significant bradycardia was noted during the neuroleptanalgesia as well as a significant tachycardia during arousal produced by diprenorphine. The former could readily be antagonized by atropine, and the latter by propranolol. It is concluded that the effect of immobilon®/revivon® on cardiovascular and respiratory parameters does not preclude its clinical use i

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03497.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract:A modified radioimmunoassay for digoxin, suitable for serum, urine and homogenized myocardial tissue, is presented. It includes an initial extraction by dichlormethane after addition of protein (gelatine, 4 g/l). A constant fraction and more than 93 per cent of the digoxin is extracted in this way. The method is suitable for pharmacokinetic studies, since the basis for standardization is aqueous solutions of digoxin, and the interference of proteins in the samples are eliminated. By this means the interference of other digitalis glycosides is reduced, and quenching correction under the final determination of the3H activity is unnecessary. The precision, including the initial extraction, is 5–7 per cen

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1974.tb03498.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY