[Modulating mechanism of the dorsal column stimulation for pain relief (author's transl)]

The neural mechanism of the modulating effects of spinal cord stimulation upon intractable pain was studied in cats under local anaesthesia. The electrical activity at the centre median nucleus of the thalamus (CEM), which responded to noxious stimuli and was inhibited by nitrous oxide inhalation, was recorded as an indicator of the degree of pain sensation. The suppressed effect upon the evoked potential responding to sciatic stimulation (1 Hz) was recorded during and after train stimulation of various parts of the spinal cord by means of silver ball bipolar electrode. Whenever inhibitory modulating effect upon CEM response was observed by spinal cord stimulation, the bilateral dorsal tractotomy cranial, caudal or both to the stimulating point in order to examine the influence upon the CEM potential. The results are as follows: 1) The CEM evoked potential responding to sciatic stimulation is inhibited by about 30-45% of its amplitude by dorsal column stimulation. This effect corresponds to the inhibitory effect by 75% N2O gas inhalation. Upon dorsal column stimulation, the intraspinal electrical activity is found in the central gray matter the antero-lateral quandrants of the spinal cord as well as the dorsal column. 2) Following lateral or anterior column stimulation as well as dorsal column stimulation, the CEM evoked potential responding to sciatic stimulation is inhibited by about 50% of its amplitude. 3) Following bilateral dorsal tractotomy cranial, caudal or both to the stimulating point, the CEM evoked potentials responding to sciatic stimulation are inhibited by dorsal column stimulation. According to the experimental results, it may be concluded that the inhibitory modulating mechanism by dorsal column stimulation for pain relief is not only mediated through the dorsal column, but also through other ascending spinal pathways.

Feed-back control of cholesterol synthesis in partially hepatectomized rats

Partial hepatectomy caused a marked stimulation of cholesterol and fatty acid syntheses without affecting serum total cholesterol, total phospholipid and triacylglycerol concentrations of rats so far examined 48 h after the operation. Serum free cholesterol level, however, was increased by the treatment and the ratio of lysophosphatidylcholine to phosphatidylcholine was concomitantly decreased, suggesting the impairment of serum lecithin: cholesterol acyltransferase activity. The lipid content in the liver, especially triacylglycerol and ester cholesterol, was increased markedly by the operation. Feeding of a high cholesterol diet which elevated serum cholesterol and phospholipid levels to the partially hepatectomized rats, accelerated the accumulation of hepatic triacylglycerol and ester cholesterol by the partial hepatectomy. The weight of the regenerating liver was not influenced by cholesterol feeding, which suggested that cholesterol feeding did not inhibit the regeneration mechanism of the liver. The increase of cholesterol synthesis after partial hepatectomy was inhibited by cholesterol feeding. Therefore, it is conceivable that the negative feed-back control of cholesterol synthesis is induced by cholesterol feeding under the stimulated cell divisions of the liver after partial hepatectomy. It is suggested from the present data that a large amount of the cholesterol which is necessary for cell growth can be taken up from serum, when serum cholesterol concentration is high.

Plethysmographic study in the patients with non-specific complaints in the head-cervico-brachial regions: with a special reference to laterality in vasomotor responses and "cervical sympathetic dysharmony"

Bilateral vasomotor responses and sweat gland activities under the control of cervical sympathetic nerves were examined simultaneously by photo-electric plethysmogram (PTG) and skin potential reflex (SPR) in patients with nonspecific complaints in the head-cervicobrachial regions such as headache, dizziness, tinnitus, pain or stiffness of the neck and shoulder, and dullness or numbness of the arms. 137 out of those 355 patients (38.6%) were revealed to have laterality in vasomotor responses, but it was only 3 in 60 normal control subjects (5%) that showed the laterality in vasomotor responses. These results supported the assumption that the cervical sympathetic dysharmony--imbalance between the right and left sides of cervical sympathetic functions--played an important role in causing their various vegetative complaints in the head-cervicobrachial regions.

Emotional slow negative potential shift (CNV) in the thalamus

In order to know the functional relationship between CNV recorded at the vertex and activity of the thalamic nucleus, the CNV at the vertex and the intrathalamic slow potentials responding to an S1-S2-R paradigm were recorded during thalamotomy under local anesthesia. It might be concluded that the activity of the medial thalamus and medial parts of the subthalamic area not only generate slow potential shifts corresponding to S1-S2-R, but also play an important role in controlling the CNV at the vertex.

Effects of dietary protein level on the energy metabolism of rats during exercise

The experiments were designed to study the effects of exercise of various intensities in albino rats fed diets containing 8 per cent or 20 per cent casein. Male rats about 7 weeks old were divided into exercise groups and control (non-exercise) groups. The exercise groups were forced to run 57 km or 76 km in total during a 28-day period. The oxygen uptake of rats was measured in order to study the influence of exercise on energy metabolism of rats and the effects of training. Body weight and food intake were also measured. 1. In all exercise groups the total amount of food intake and body weight gain during the exercise period were smaller than those of the control groups, regardless of the protein levels of the diets. but while the rats were kept at rest after the exercise period, the food intake and body weight of these groups increased and approached those of the control groups. 2. No difference in resting metabolism was observed both in the 8 per cent and 20 per cent casein groups. At lower speeds up to 1.5 km/hr the 8 per cent casein group indicated lower oxygen requirement during the exercise but at speeds higher than 2.0 km/hr the oxygen requirement was definitely higher than that of the 20 per cent casein group. The estimated optimum speed for rats weighing 300 g on the average is somewhere between 1.5 and 2.0 km/hr is calculated on the basis of oxygen requirement for running 100 m. 3. The obvious effects of training on oxygen uptake were seen in the 20 per cent casein group after four weeks' training, although no effect was found in the 8 per cent casein group.