Preliminary experimental experiences with xenotransplantations.

In our xenotransplantation experiments has been a major aim to induce specific tolerance. The results from the meeting of the donor's and the recipient's immunocompetent systems already in the period of embryonic development and/or the influence of methylprednisolone are described.

Ethanol and physostigmine effects on open field behavior in Wistar rats.

The paper is aimed at the evaluation the effect of relatively low doses of ethanol and physostigmine salicylate on behavior of the male Wistar rat in an open field test. Both drugs were administered as a solution intragastrically 1 hour before the test started in dose ranges of 0.6-1.8 g/kg and 0.06-0.18 mg/kg, respectively. Lower doses of ethanol showed dose dependent biphasic effect on the ambulation and grooming time in animals. The medium dose 1.2 g/kg was rather ineffective in affecting rat behavior in the hole board test. Individual variables showed different sensitivity to individual ethanol doses. But from the medium dose, individual manifestations of ataxia were observed. Using the dose, only total ambulation, rearing time and rear latency were not affected when the rats were experienced with repeated exposure to open field arena or ethanol dose beforehand. Physostigmine alone increased defecation level significantly by two doses but lower doses changed some of the other variables, too. Combined administration of both drugs in medium doses did not affect the rat behavior considerably. The intra-trial habituation of three parameters of OF behavior seems to be influenced differently. Ethanol showed a tendency to facilitate the habituation of rearing, but rather to interfere with that of grooming. The later effect was also shown for physostigmine 0.12 mg/kg. The experimental part of the paper is supplied by the discussion of aspects important for modulation of rodent behavior in an open field test.

Effect of some drugs, experimental stress and estrus on unstable and fixed conditioned alimentary motor reflexes in cats. Meclophenoxate, chlorprothixen, caffeine, piracetam. Part VI.

A group of 10 cats, both sexes, were studied for the effect of peroral administration of the meclophenoxate (Cetrexin, Léciva, 1.5 mg kg-1) + chlorprothixen (Chlorprothixen, Spofa, 0.045 mg kg-1) + caffeine (Coffeinum natrium benzoicum, Spofa, 0.15 mg kg-1) combination upon the fixation of conditioned alimentary motor reflexes to a sound signal in the course of a 10-week experiment. The mentioned combination of drugs demonstrated a beneficial protective influence on the fixed alimentary motor reflexes against laboratory stress. The results were compared with the earlier fixation of the same reflexes in another group of 11 cats under piracetam (Nootropil, U.C.B. 20 mg kg-1, s.c.). In both groups of animals, the development of reflexes was performed in regular alterations of experiments under the effect of the drugs and control experiments. The drugs were administered 1 hour before the experiments. Both groups of animals showed significantly fewer intersignal and other incorrect motor reactions on the days they were given the drugs than the controls did. The number of fixed correct reactions and their latencies displayed only moderate insignificant differences between the pharmacological trials and the controls. The conclusions is that the actual development of conditioned alimentary motor reflexes was not found to be influenced by the action of the mentioned drugs modifying psychological functions and mental states.

Effects of ethanol and physostigmine on reproduction of conditioned alimentary motor reflexes in cats--interaction with stress.

A group of 10 chronic cats with firmly established conditioned food motor reflexes were studied for the effect of various doses of physostigmine salicylate and its combination with 0.6 g/kg of ethanol. The trials were taking place one hour after peroral administration of the substances to non-stimulated and stimulated animals with synchronized intermittent light and sound. The reproduction of conditioned reflexes was not impaired in any of the trials with 0.009 to 0.15 mg/kg of physostigmine alone or its combination with ethanol. The most stable indicator of performance proved to be the mean value of the number of the correct responses. Correct response latencies and the number of incorrect reactions were influenced by doses up to 0.12 mg/kg only insignificantly. The highest dose of physostigmine significantly prolonged the latencies and, at the same time, reduced the number of incorrect responses. The physostigmine-ethanol combination, compared with physostigmine alone, did not show any shift in the range and direction of changes of latencies and incorrect responses against the controls. Stressing the animals in the experiment with the combination of 0.06 mg/kg of physostigmine with ethanol was reflected in a significant change in the influence on correct response latencies. An inverse tendency to shorten correct response latencies due to the effect of sensory stimulation against the controls in comparison with nonstimulated animals can mean a nonspecific activation of the cats' operant behaviour due to the stressor.