[Effect of interoceptive stimulation of the stomach on photically evoked potentials of the visual cortex with reference to blood pressure and heart rate in the cat].

In ten chloralose narcotized, relaxed and constantly oxygenated cats the stomachs were dilated with two different pressures in acute experiments. Photically evoked potentials (PEP) were derived from the visual cortex of the animals. The aim of the work was to find out in which respect the processing of an exteroreceptive stimulus (light stimulus of only 200 ms) in the visual analyzer can be influenced by an interoceptive stimulation. Besides, it had to be established to which extent the visceral stimulation leads to a change of other vegetative parameters. Qualitative alterations of different PEP-parameters, blood pressure and heart rate of the experimental animals were examined at different stomach pressures. Changes of the positive and negative amplitudes and the time of the negative component of the primary complex of the evoked potential have been observed. Moreover, there could be registered an increase in blood pressure depending on the height of stomach pressure. The heart rate was not influenced. Further studies will have to clarify whether the changes of the PEP are produced by the interoreceptive stimulus or by the changes of blood pressure or respiration.