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Changes of evoked potentials under the influence of NBQX (a non-NMDA receptor antagonist), MK-801 (a NMDA receptor antagonist) and GDEE (a nonselective antagonist of glutamate receptor) were studied. GDEE augmented potentiation and was marked progression of potentiation with increasing number of stimuli. There was no potentiation of responses in relation to the number of stimulus in a series in experiments with both MK-801 and NBQX. Interpretation of results with NBQX and MK-801 is difficult.

The effect of growth stimulators Carbadox and Cyadox was studied in laboratory rats and mice as exerted on their fertility, gravidity, embryo ontogenesis, and genetic efficacy of these drugs was also tested. In all tests one dose approaching the dose used in practice and multiple doses were administered. No antifertility effects were observed in either sex of rats, slight reduction in fertility was found in treated male mice. No teratogenic effect was observed, but both stimulators acted highly embryotoxically. Irrespective of the dose, genetic hazard occurred, influencing the first stages of spermatogenesis (spermatogony), and increasing the incidence ob abnormalities of spermatozoon heads after Carbadox treatment. In all tests Cyadox was less harmful than Carbadox. The results show that it is somewhat hazardous to use both growth stimulators in the period of animal reproduction.

For a period of 14 days, piglets from six litters, weaned between the 25th and 28th day of age, were fed the COS 2 starter containing either a premix with furazolidone or carboadox of Czechoslovak origin. Bentonite hydrosilicate was used as a carrier in both cases. Furazolidone administered in the dose of 200 mg per 1 kg of feed prevented diarrhoea, insignificantly increased body weight gain, and decreased the consumption of feed per 1 kg of gain from 5.6 kg in the control to 4.0 kg in the test animals. Carbadox administered in the dose of 50 mg per 1 kg of feed suppressed the signs of enteritis in comparison with the control piglets, significantly increased body weight gains, and reduced feed consumption to 1.9 kg per 1 kg of gain. No differences were recorded in the concentration of blood glucose, total protein, and total cholesterol in plasma. The control piglets showed increased parameters of the adrenocortical function. The proportion (percentage) of haemolytic E. coli in rectum was affected neither by carbadox nor by furazolidone; furazolidone suppressed the occurrence of lactoso-negative strains. An insignificant drop of the number of haemolytic E. coki in the duodenum and jejunum of the furazolidone-and carbadox-treated piglets was observed after 14 days. With their clinical effects, the two substances tested manifest themselves as suitable for the reduction of losses in weaned piglets.