A study was made in unanesthetized rabbits of the changes in intestinal movement due to electric stimulation on the limbic system in reference to electrical activities of the central nervous system.
1. Following 3 Hz stimulation given to the amygdaloid nucleus, the development of spike and wave in EEG of the cerebral cortex and hippocampus was accompanied by a facilitated intestinal movement.
2. When the frequency of stimulation was increased from 3 to 8 Hz, recruiting response began to appear, followed by either facilitation or inhibition of intestinal movement.
3. With 100Hz stimulation given to the amygdaloid nucleus, the arousal pattern appeared in EEG, followed by a marked inhibition of intestinal movement, being accompanied by tonic type or tonic phasic type evoked muscular discharges in the fore and hind limbs,
4. The area for the intestinal inhibition only tended to be located centered on the central nucleus, while the area for both facilitation and inhibition located diffusely in the amygdaloid nucleus.
5. It was demonstrated that the facilitatory impulse due to stimulation of the amygdaloid nucleus passed through the vagus nerve while the inhibitory one passed through the splanchnic nerve.
6. Stimulation (3,8,100Hz) of the hippocampus resulted in no marked changes in intestinal movement.
7. Studies on the effects of various drugs on EEG and inhibition of intestinal movement revealed that the regulation of amygdaloid nucleus for intestinal movement was carried out through the lower center.
8. The amygdaloid nucleus influenced intestinal movement most markedly, followed by the septal nucleus and midbrain reticular formation in order.
9. The inhibitory effect due to stimulation of the amygdaloid nucleus was abolished by a destruction of the hypothalamus (DMH), unlike the case with the inhibitory effect due to stimulation of the reticular formation.
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