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《Micron and Microscopica Acta》1988,19(4):227-234
A considerable number of studies were carried out on patients receiving Cyclosporin A (CSA) after bone marrow, heart and kidney transplants. More recently this drug has been used as an immunosuppressive agent in the management of type 1 diabetes. Moreover the increase of creatinine levels in CSA-treated patients and animals has led the researchers to believe that this drug may be responsible for irreversible nephrotubular side effects.Our aim was, therefore, to study the hispathological effects of CSA on kidneys of bio breeding (BB) rats, which develop diabetes spontaneously.Animals were treated for 30 and 60 days with daily injections of 8 mg/kg body wt of CSA, dissolved in 2 ml of Intralipid 10% (Pierrel), given intraperitoneally (control animals received only Intralipid). At the end of the experiments animals were sacrificed under ether anaesthesia and the kidneys removed and processed for light microscopy, using standard procedures. After a 30-day administration of CSA, the tubular and glomerular structures appeared unchanged or, in some cases, only a few cells, in the proximal tubules, showed slight vacuolation. After 60 days of CSA administration, the elements of the proximal profiles showed a considerable degree of cytoplasmic vacuolation. These vacuoles resulted positive to PFABB, Sudan Black B, PAS and alkaline tetrazolium reactions. Distal tubular profiles, loops of Henle and glomeruli were unaffected.Our morphological findings demonstrate that CSA causes nephrotubular modifications, when administered in therapeutic doses of only 10 mg/kg body wt, as in many clinical schedules. Moreover data could be consistent with a possible reversion to the normal structural appearance. 相似文献
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It is shown that systemic injections of analgin and ketorolac in doses equivalent to those used in clinics induce antinociception
in awake rats (tail-flick test) and, when carried out repetitively, induce tolerance to these agents and cross-tolerance to
morphine (blocked by naloxone).
Neirofiziologiya/Neurophysiology, Vol. 38, No. 4, pp. 370–373, July–August, 2006. 相似文献
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Monson C. B.; Patterson S. L.; Horowitz J. M.; Oyama J. 《Journal of applied physiology》1989,67(1):383-389
To determine the effect of hypergravity acclimation on thermoregulation, core temperature (Tc), tail temperature (Tt), and O2 consumption (VO2) were measured in control rats (raised at 1 G) and in rats acclimated to 2.1 G. When the animals were exposed to a low ambient temperature of 9 degrees C, concurrently with a hypergravic field of 2.1 G, Tc of rats raised at 1 G fell markedly by approximately 6 degrees C (to 30.8 +/- 0.6 degrees C) while that of the rats raised at 2.1 G remained relatively constant (falling only approximately 1 degree C to 36.4 +/- 0.3 degrees C). Thus prior acclimation to a 2.1-G field enabled rats to maintain Tc when cold exposed in a 2.1-G field. To maintain Tc, thermogenic mechanisms were successfully activated in the 2.1-G-acclimated rats as shown by measurements of VO2. In contrast, VO2 measurements showed that rats reared at 1 G and then cold exposed at 2.1 G did not activate thermogenic mechanisms sufficiently to prevent a fall in Tc. In other experiments, rats acclimated to either 1 or 2.1 G were found to lack the ability to maintain their Tc when exposed to a 5.8-G field or when exposed to prolonged cold exposure at 1 G. Results are interpreted as showing that when placed in a 2.1-G field, rats acclimated to 2.1 G can more closely maintain their Tc near 37 degrees C when cold exposed than can rats acclimated to 1 G. However, this enhanced regulatory ability of 2.1-G-acclimated rats over 1.0-G-acclimated rats is restricted to 2.1-G fields and is not observed in 1.0- and 5.8-G fields. 相似文献
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Six groups of rats were presented with alternating 45-sec accessperiods to two tubes containing sucrose solutions. On some daysone group experienced a disparity in solution concentration(16% vs. 2%, 16% vs. 4%, 16% vs. 8%, and 16% vs. 12%) and onother days received the same concentration solution in bothtubes (16%, 12%, 8%, 4%, or 2%). Each of the remaining fivegroups received only one concentration solution in both tubesthroughout the experiment (16%, 12%, 8%, 4%, or 2%). Lick ratesto the different concentration solutions obtained under comparisonconditions were found to be exaggerated relative to those obtainedunder non-comparison conditions (contrast). Regression analysesperformed on the log lick ratios to the various concentrationsplotted as a function of the log ratios of the concentrationsavailable, revealed a good fit to a power function with an exponent(slope) within the range of those found in human judgments ofrelative sweetness. The slopes obtained from the regressionanalyses were a) steeper under comparison than under non-comparisoncondition and b) increased as number of within-session comparisonsincreased. The results are discussed in terms of a sensoryperceptualinterpretation of contrast effects. 相似文献
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Nicotine dependence in rats 总被引:2,自引:0,他引:2
Health hazards associated with nicotine and tobacco use are well known. A contributing factor, the dependence producing potential of this drug, has become widely accepted. However, there are only a few human and animal studies that provide objective measures of the behavioral consequences of nicotine abstinence. The purpose of the present experiment was to use sensitive measures to examine behavioral disruptions that resulted when nicotine administration was terminated. Six rats were administered 96 daily intravenous infusions of nicotine (0.125 mg/kg/infusion) for at least 10 days. They were trained to respond on a tongue-operated solenoid-driven drinking device that delivered 0.005 ml of a glucose and saccharin solution (G + S) per lick. When nicotine access was terminated for six days, there was a marked suppression in behavior reinforced by the sweetened solution, and this disruption was immediately reversed when nicotine was reinstated. In contrast, nicotine removal also resulted in a decrease in food intake on the first day, but on subsequent days food intake was significantly higher than when nicotine was administered. When cotinine (0.25 mg/kg/infusion), a metabolite of nicotine was substituted for nicotine for six days, similar disruptions resulted in responding maintained by G + S, but food intake was not significantly decreased on the first day of nicotine abstinence. These findings illustrate the utility of sensitive behavioral tests to reveal effects of nicotine abstinence. 相似文献
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Hyperlipidemia occurs in animals bearing tumors but the mechanism of its development is uncertain. We have measured triacylglycerol clearance and production rate in rats bearing a transplantable sarcoma. The plasma content of very-low-density lipoprotein triacylglycerol was increased in these tumor-bearing rats but our data excluded a primary clearance defect because the rate of triacylglycerol accumulation (mg/min) after Triton injection was equal to or greater than in normal control rats, except in cachectic rats with very large tumors. The fractional clearance of injected radioactive triacylglycerols was less in tumor-bearing rats than in controls, but the turnover (mg/min) was probably not decreased in the tumor-bearing rats because of their expanded plasma pool. Also inconsistent with a decreased turnover was our finding of a greater production of radioactive plasma triacylglycerols after injection of a tracer dose of radioactive free fatty acid, and unchanged production in Triton-treated rats. Therefore, in the fasted state, the hyperlipidemia of the tumor-bearing rats was associated with an unchanged or possibly an increased flux of hepatic triacylglycerols and a primary clearance defect was excluded. After fat-feeding, rats with tumors developed a higher post-prandial hyperlipidemia than control rats. Therefore, the clearance mechanism for the plasma triacylglycerols was close to saturation in the fasted state, and the added influx of exogenous triacylglycerols was removed less efficiently in the tumor-bearing rats. 相似文献
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The evolution of cooperation among nonrelatives has been explained by direct, indirect, and strong reciprocity. Animals should base the decision to help others on expected future help, which they may judge from past behavior of their partner. Although many examples of cooperative behavior exist in nature where reciprocity may be involved, experimental evidence for strategies predicted by direct reciprocity models remains controversial; and indirect and strong reciprocity have been found only in humans so far. Here we show experimentally that cooperative behavior of female rats is influenced by prior receipt of help, irrespective of the identity of the partner. Rats that were trained in an instrumental cooperative task (pulling a stick in order to produce food for a partner) pulled more often for an unknown partner after they were helped than if they had not received help before. This alternative mechanism, called generalized reciprocity, requires no specific knowledge about the partner and may promote the evolution of cooperation among unfamiliar nonrelatives. 相似文献
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S S Bo?ko V P Zherdev A A Dvorianinov I Janku E Buchar 《Biulleten' eksperimental'no? biologii i meditsiny》1990,110(11):501-503
Pharmacokinetics of novel immunostimulating drug kamantane was studied by using gas-liquid chromatography in experiments on rats. It was found that kemantane biotransformed rapidly after oral administration with the forming of active metabolite. Kemantane and its metabolites are distributed rapidly from the blood to organs. The drug is eliminated from the organism of rats as metabolite. 相似文献