Abstract
It was found previously that inhibition of the flexor reflex of the frog lower extremities during animal hypnosis caused by inversion in response to the electrical skin stimulation, was abolished after caudal transection of the brainstem, but not by rostral transection of it, and that animal hypnosis caused by inversion of the rabbits was abolished after electrical lesion around the brachium conjunctivum lateral to the 4th ventricle in the pons.
The hard pressure on the part of the body is known as one of the induction methods to produce animal hypnosis. Recently the Bi-digital O-ring test was proposed by Dr. Omura as the new diagnostic method. In this test, the voluntary flexion of the fingers making O-ring is inhibited by light touch of the restricted area in the skin responded to this test and is useful to diagnose the internal organ since finding such skin region is the procedure to find out the corresponding internal diseased organ. The present experiment was undertaken to investigate the underlying neuronal mechanism of this test in the experimental gastro-duodenal ulcer sufferring animals, and whether inhibition of the flexor finger muscle movement in O-ring test is mediated by the central mechanism of the flexor reflex inhibition in animal hypnosis or by simple reflex inhibition in the spinal cord. For this purpose, the flexor muscle movement caused by stimulation of the motor cortex is employed as the experimental model of the voluntary finger flexion in the O-ring test.
The flexor muscle electromyogram (EMG) of the upper extremities in response to the motor cortex stimulation was inhibited by hard hand pressure on base of the ear lobe and lumbar perivertebral region and by electrical stimulation of these regions. Similar inhibition was produced by electrical stimulation around the brachium conjunctivum and locus coeruleus (BC-LC) and the reticulogigantocellular nucleus (NRGC). Inhibition of the flexor muscle EMG due to hard pressure on the body parts was abolished by electrical lesioning of the BC-LC and NRGC.
The light pinch with hand on the restricted abdominal region did not inhibit the flexor muscle EMG induced by the motor cortex stimulation in normal condition, while such stimulation inhibited the flexor muscle EMG in the ulcer sufferring animals after treatment with cysteamine. This inhibition was not influenced by destruction of the NRGC.
From these results, it was concluded that inhibition of the motor cortex induced-flexor muscle activities caused by light pinch stimulation of the restricted abdominal region, as the model of the voluntary finger flexion inhibition in O-ring test, was produced by spinal reflex inhibition.
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