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.