Common projection of the motor cortex to the caudate nucleus and the cerebellum

1. Stimulation of the caudate nucleus (Cd) was found to evoke early mossy fibre (MF) and late climbing fibre (CF) responses in fairly wide areas of the cerebellar cortex in cats. Points capable of eliciting the cerebellar responses were situated exclusively in the head portion of the nucleus. These responses showed a close resemblance to those induced by stimulation of the medial part of the anterior sigmoid gyrus (ASG) both in their contours and in their distributions. 2. There was a remarkable interaction between the Cd- and the medial ASG-induced field potentials in the pontine nuclei. When conditioned by the Cd stimulation at significantly short time intervals, the field potentials evoked by the medial ASG stimulation were more remarkably suppressed than those by the lateral ASG stimulation. 3. Field potentials or extracellular unitary activities in the inferior olive elicited by the Cd stimulation were closely related to those evoked by the medial ASG stimulation both in their responsiveness and in their topographical localizations. 4. When the cortical motor area had been ablated 10--14 days previously, the Cd stimulation elicited no responses in the cerebellar cortex. 5. From these findings, it was indicated that the Cd receives collaterals of the cortico-pontine and/or the cortico-olivary axons that originated almost exclusively from the neurones in the medial ASG (area 6). This suggested the existence of a common innervation of the basal ganglia and the cerebellar systems by the premotor area of the cerebral cortex.

Isolation of 4.5-dihydroxyisophthalic acid an inhibitor of brain glutamate decarboxylase, produced by a Streptomyces species

A potent inhibitor of brain glutamate decarboxylase (L-glutamate 1-carboxy-lyase, EC 4.1.1.15) was isolated from cultures of a Streptomyces species, and its structure was found to be 4,5-dihydroxyisophthalic acid. The metabolite inhibited beef brain glutamate decarboxylase 50% at a concentration of 0.12 microgram/ml (0.61 micron). The kinetic analysis indicated that 4,5-dihydroxyisophthalic acid was a competitive inhibitor having a Ki value of 0.18 micron.

Traumatic spreading depression syndrome. Review of a particular type of head injury in 37 patients

From 1476 hospital admissions with head injury, 37 patients were selected on the basis of distinctive clinical features which appeared to share a single and benign aetiology. In head injuries of this type, transient neurological disorders resulted from trivial or rather mild head injuries. These disorders, which included headache, nausea and vomiting, pallor, somnolence, irritability and restlessness, stupor, hemiparesis and aphasia, appeared after a lucid interval which was usually less than two hours; then the patient either recovered, or went on to develop convulsive attacks. Recovery without convulsions was usual in children and adolescents; convulsions occurred both in infants and younger children. The symptoms were not attributable to cerebral compression but were probably due to a self-limiting cortical phenomenon. It appears that convulsive attacks occurring within a few hours of this type of head injury may not be significant as precursors of post-traumatic epilepsy. It is suggested that there is a close relation between the convulsive attacks and the non-convulsive symptoms seen in this type of injury and that both are based on a common process which has the characteristics of the spreading depression of Leão. This type of head injury should be classified as a distinct clinical entity, in which no surgical treatment is required and the prognosis is good.

Effects of stimulation of the midbrain reticular formation upon thalamo-cortical neurones responsible for cortical recruiting responses

1. In lightly nembutalized cats, effects of high frequency (60-100/sec) repetitive stimulation of the midbrain reticular formation (RF) were tested upon the thalamo-cortical (T-C) neurones which project from the anterior ventral (VA) nucleus of the thalamus and its vicinities to the parietal association cortex and convey impulses responsible for cortical recruiting and spindling-like responses. 2. Tonic maintained or rhythmic grouped firings of the T-C neurones recorded as extracellular units with microelectrode in the thalamus were in the majority suppressed by high frequency RF stimulation during and often for a short time after the stimulation, and they showed later tonic discharges for many seconds or minutes. Intracellular recording from the T-C neurones revealed hyperpolarizing potential changes corresponding to the suppression on high frequency RF stimulation. Field potential analysis in the VA nucleus indicated that the hyperpolarization is ascribed at least in part to IPSPs elicited in the T-C neurones. Responses in some other types of thalamic neurones to the RF stimulation were exemplified to be compared and related with those of the T-C neurones. 3. Desynchronization of the parietal electrocorticogram coincided with the suppression of the T-C neurones and lasted for the time of the later tonic discharges, which contrasted with the rhythmic grouped discharges of the T-C neurones in association with recruiting and spindling-like responses of the cortex. Relations between the thalamo-cortical recruiting system and the ascending reticular activating system were discussed.

Effects of mannoheptulose and DL-glyceraldehyde on glucose induced insulin release and adenosine 3',5'-monophosphate levels in isoalted islets of rat pancreas

The effects of mannoheptulose and DL-glyceraldehyde on glucose-induced insulin release and cycli AMP levels in islets isolated from rat pancreas were investigated. Mannoheptulose inhibition on glucose-induced insulin release was observed after only 5-min incubation period, indicating an inhibitory effect on the early phase of insulin release. This inhibition on insulin release was accompanied with the simultaneous depression of cyclic AMP levels in islets. By the addition of DL-glyceraldehyde to the medium in which glucose and mannoheptulose were present, the depressed cyclic AMP levels in islets were recovered to the control level completely but the restoration of insulin release in the early phase was not complete. In the absence of glucose, DL-glyceraldehyde did not demonstrate a significant increase of insulin release during 5 min incubation, though a marked stimulation was observed after 30-min incubation. Cyclic AMP levels in islets were not affected by DL-glyceraldehyde. When DL-glyceraldehyde was added to the medium with glucose, significant inhibition of glucos-induced insulin release in its early phase was observed without the reduction of cyclic AMP levels in islets. From these findings, the following possibilities are suggested and discussed. 1. Maintenance of the cyclic AMP levels in islets is a necessary but insufficient condition for glucose-induced insulin release particularly for its early phase. 2. Glucose-induced insulin release seems to depend on both the binding of glucose with glucoreceptor and the supply of some metabolites. Mannoheptulose inhibits both mechanisms. DL-glyceraldehyde may supply metabolites but competitively inhibit the binding of glucose to the glucoreceptor.

Effects of concanavalin A and neuraminidase on cyclic AMP levels and 14C-1-glucose oxidation in dog thyroid slices

Treatment with concanavalin A at 100 micron/ml or higher concentrations significantly increased 14C-1-glucose oxidation in dog thyroid slices as reported in other tissues. This treatment exerted no effect on tissue cyclic AMP levels. Neuraminidase at the same concentrations also had similar effects on these parameters. Neither concanavalin A nor neuraminidase at the concentrations up to 100 microng/ml had the TSH effect on both tissue cyclic AMP and 14C-1-glucose oxidation. These results indicate that modification of carbohydrate moieties of glycoproteins on the cell surface may cause an increase in glucose metabolism without any critical effect on cyclic AMP system and in the process of TSH response.

Inhibition of insulin release by synthetic rat C-peptide II in isolated rat islets

The effect of synthetic rat C-peptide on glucose-induced insulin release was studied in isolated islets of rat pancreas. Addition of rat C-peptide II to the medium inhibited glucose-induced insulin release from islets by 30 to 40 percent. Rat C-peptide I, human connecting peptide and bovine, porcine and canine C-peptides had no significant effects on insulin release from islets of rat pancreas.

Electrophysiological studies on the cerebellocerebral projections in monkeys

1. Responses evoked by stimulation of the cerebellar and thalamic nuclei were recorded by microelectrodes introduced at various depths in the cerebral cortex of monkeys (Macaca mulatta) under light Nembutal anaesthesia. 2. Stimulation of the medial (fastigial) cerebellar nucleus produced, at a latency of 4-5 msec, deep thalamo-cortical (T-C) responses (surface positive-deep negative potentials) mainly in the medial part of the precentral gyrus (area 4, "motor area for hindlimb") and in the superior parietal gyrus (area 5) on both contralateral and ipsilateral sides to the nucleus stimulated. 3. Stimulation of the lateral (dentate) cerebellar nucleus elicited, at a latency of about 3 msec, superficial T-C responses (surface negative-deep positive potentials) predominately in the lateral part of the precentral gyrus (area 4, "motor area for forelimb and face") and in the rostromedial part of the gyrus (area 6, premotor area) on the contralateral side. 4. Stimulation of the interpositus cerebellar nucleus set up superficial T-C responses chiefly in the motor area between those influenced by the medial and the lateral cerebellar nucleus stimulation and also in the premotor area on the contralateral side. 5. The respective areas responsive to the medial, interpositus and lateral nucleus stimulation overlapped considerably each other in the motor cortex. 6. Comparison of the responses in the cortex induced by stimulation of the cerebellar and thalamic nuclei indicated different relay portions in and around the VA-VL region of the thalamus for the superficial and the deep T-C responses respectively. 7. Functional implications of the results were discussed in referring to the cerebellocerebral projections in cats.

Increased urinary excretion of L-xylulose in patients with liver cirrhosis

The urinary excretions of L-xylulose, xylitol and D-glucarate after the oral administration of glucuronolactone (5 g) were measured in normal healthy persons, patients with diabetes mellitus, acute hepatitis in recovery stage, chronic hepatitis and liver cirrhosis. In normal subjects, the mean value of L-xylulose excretion was 14.6 +/- 1.4 mumol/2 h with a range from 6.5 to 21.8. Marked increase of L-xylulose excretion was observed in cirrhotic patients, the mean value was 97.1 +/- 19.8 with a range from 22.0 to 236.6. Though some cases of acute and chronic hepatitis showed higher values than the normal range, no case exceeded 50 mumol/2 h. The urinary excretion of xylitol in cirrhotic patients was also higher than normal no increase was observed in D-glucarate excretion. The values of L-xylulose excretion in cirrhosis were correlated with the values of serum total bilirubin, albumin, albumin/globulin ratio, lactate dehydrogenase and prothrombin time. These findings indicate that the measurement of L-xylulose in urine after the oral glucuronolactone loading provides a useful tool for evaluation of the severity of liver cirrhosis.

Impairment and restoration of response to TSH in dog thyroid slices after treatment with phospholipase A and lubrol PX

Incubation of dog thyroid slices with phospholipase A (10-40 U/Ml) or Lubrol PX (0.08-0.4%) caused a diminution in the subsequent TSH effect on the tissue cyclic AMP level and glucose oxidation. The same treatment had no effect on the basal level of these parameters. When the phospholipase A or Lubrol PX-treated slices were rinsed intensively with a Krebs-Ringer bicarbonate buffer and then incubated at 37degreesC in the same buffer for a further 1 to 3 hours, responsiveness to TSH recovered progressively reaching almost completely that of the control slices. Again, these procedures were without any significant effect on the responsiveness of the control slices. The above results together with those reported previously suggest strongly that phospholipids are an essential component of the plasma membrane system by which TSH stimulates adenylate cyclase activity. In addition, these essential lipids in the membrane appear to be renewed rather efficiently in this tissue, thus securing the functional integrity of the thyroid in the face of various deleterious situations.

Effect of glucose on adenosine 3', 5'-monophosphate levels in rat pancreatic islets

Time course of the changes in insulin release and cyclic AMP levels in isolated rat islets incubated in media containing 5 or 16.7 mM of glucose were followed. The higher glucose concentration caused a slight but significant increase of cyclic AMP levels after 10 min incubation, but not 5 min incubation, whereas the stimulation of insulin release by 16.7 mM of glucose was apparent in both incubation times. Theophylline increased cyclic AMP levels markedly but did not stimulate insulin release when the glucose concentration was 5 mM. A slight augmentation by theophylline of insulin release was observed in the incubation medium containing 16.7 mM glucose. All these findings suggest that the elevation of cyclic AMP in islets may not play a role for the initiation of the insulin release induced by glucose, though it may act to modulate the glucose effect.

Subfractionation of rat liver plasma membrane. Uneven distribution of plasma membrane-bound enzymes on the liver cell surface

Plasma membranes were isolated from rat liver mainly under isotonic conditions. As marker enzymes for the plasma membrane, 5'-nucleotidase and (Na+ + K+)-ATPase were used. The yield of plasma membrane was 0.6-0.9 mg protein per g wet weight of liver. The recovery of 5'-nucleotidase and (Na+ +K+)-ATPase activity was 18 and 48% of the total activity of the whole-liver homogenate, respectively. Judged from the activity of glucose-6-phosphatase and succinate dehydrogenase in the plasma membrane, and from the electron microscopic observation of it, the contamination by microsomes and mitochondria was very low. A further homogenization of the plasma membrane yielded two fractions, the light and heavy fractions, in a discontinuous sucrose gradient centrifugation. The light fraction showed higher specific activities of 5'-nucleotidase, alkaline phosphatase, (Na+ +K+)-ATPase and Mg2+-ATPase, whereas the heavy one showed a higher specific activity of adenylate cyclase. Ligation of the bile duct for 48 h decreased the specific activities of (Na2+ +K+)-ATPase and Mg2+-ATPase in the light fraction, whereas it had no significant influence on the activities of these enzymes in the heavy fraction. The specific activity of alkaline phosphate was elevated in both fractions by the obstruction of the bile flow. Electron microscopy on sections of the plasma membrane subfractions showed that the light fraction consisted of vesicles of various sizes and that the heavy fractions contained membrane sheets and paired membrane strips connected by junctional complexes, as well as vesicles. The origin of these two fractions is discussed and it is suggested that the light fraction was derived from the bile front of the liver cell surface and the heavy one contained the blood front and the lateral surface of it.

Effects of calcium ionophore (A-23187) on glucose oxidation and iodide transport in dog thyroid slices

A calcium ionophore (A-23187, 20 mug/ml) stimulted 14C-1-glucose oxidation in dog thyroid slices to an extent equivalent to that obtained by the optimal concentration of dibutyryl cyclic AMP (1mM). Furthermore, the ionophore augmented the stimulation by dibutyryl cyclic AMP much more than the simple additive effect. The ionophore also enhanced the effect of TSH, but to a lesser extent. Under conditions where organic binding was blocked, T/M ratio of radioiodine concentration was lowered in slices by the ionophore; the findings similar to those obtained with TSH and dibutyryl cyclic AMP. The ionophore exhibited a slightly depressive effect on the basal cyclic AMP level. The elevation by TSH of cyclic AMP levels was also slightly depressed by the ionophore, but statistically insignificant in most cases. These results indicate that calcium ion may play an important role in the TSH regulation of iodide transport and glucose metabolism in the thyroid, in some cases by augmenting the effects of cyclic AMP.

Responses of pontocerebellar neurones to stimulation of the parietal association and the frontal motor cortices

The corticopontine projections from the parietal association cortex (the anterior portion of the middle suprasylvian gyrus) were electrophysiologically investigated and compared with those from the frontal motor cortex (the anterior sigmoid gyrus) in cats under light Nembutal anaesthesia. It was indicated by field potential study that the pontine nucleus (PN) neurones receive a significant amount of the direct corticopontine fibres from both the parietal and frontal cortical areas. In extracellular unitary study, out of 107 PN neurones identified by antidromic activation due to the brachium pontis stimulation, 33 responded with firings to stimulation of the parietal association area and 64 to the frontal motor area. Only 10 of them were excited by both parietal and frontal stimulations, but they were not estimated to receive the dual monosynaptic projections from both cortical areas. There were found data suggesting that the pontocerebellar neurones with faster conduction velocities respond at shorter latencies to the cortical stimulation and those with slower conduction velocities fire at longer latencies on the cortical stimulation. No remarkable difference was observed between the topographical localization of the PN neurones receiving the projection fibres from the parietal association and the frontal motor cortical areas. It was concluded that a vast majority of the pontocerebellar neurones possibly receive monosynaptic contacts differentially with the corticopontine fibres originating from the parietal association and the frontal motor areas.

Electrophysiological studies of the projections from the parietal association area to the cerebellar cortex

1. Responses evoked in the cerebellar cortex by stimulation of the parietal association cortex (rostral portions of the middle suprasylvian gyrus) were recorded and analysed in cats, and were compared with those by stimulation of the motor cortex (anterior sigmoid gyrus). 2. The parietal stimulation elicited early mossy fibre and late climbing fibre responses in the cerebellar cortex. The mossy fibre responses appeared at a latency of 2.0--2.5 msec and predominantly in the lateral (hemispherical) part of the contralateral cerebellum (mainly crus I, crus II and paramedian lobules). Cutting of the inferior cerebellar peduncle produced little or no influence upon the mossy fibre responses, which suggests that the mossy fibre responses are mediated chiefly by the pontine nuclei. 3. The climbing fibre responses were recorded at a latency of 17--19 msec and markedly in the contralateral intermediate and medial parts of IV--VI lobules. The responses were easily sppressed by anaesthesia and depended on the conditions of experimental animals. The unstable appearance of the responses and their longer latencies than those of the climbing fibre responses due to stimulation of the motor cortex imply indirect pathways from the parietal association cortex to the inferior olive. 4. The predominant projection of the parietal-induced mossy fibre responses to the lateral part of the cerebellum was compared with the mossy fibre projection from the motor cortex and was discussed as an important component in the cerebrocerebellar loops.

Demonstration of C-peptide immunoreactivity in various body fluids and clinical evaluation of the determination of urinary C-peptide immunoreactivity

C-peptide immunoreactivity (CPR) was demonstrated not only in plasma, but in urine, ascites, cerebrospinal fluid and pleural effusion. The concentration of CPR in urine was very high compared with that in the other body fluids and was easy to assay. CPR in urine after glucose administration or tolbutamide injection increased parallel to the change of CPR in plasma and also to that of IRI in normals or diabetics without renal disturbances. The result suggest that the determination of CPR in urine before and after stimulation of insulin secretion could serve as a simple indicator of insulin secretory function of pancreas.

Thalamo-cortical projections for recruiting responses and spindling-like responses in the parietal cortex

1. The thalamic neurones sending their axons to the parietal association cortex (middle suprasylvian gyrus) and receiving monosynaptic excitation from the cerebellar (interpositus or lateral) nucleus were recorded with microelectrodes extracellularly and intracellularly around the anterior ventral (VA) nucleus of the thalamus in cats. Such thalamic neurones are known to carry exclusively the impulses responsible for superficial thalamo-cortical (T-C) responses in the parietal cortex, being called superficial T-C neurones (see Sasaki et al., 1972a, b). 2. Repetitive (6--9/sec) stimulation of the centrum medianum-parafascicular complex (CM) or the intralaminar nuclei (IL) of the thalamus elicited grouped spike discharges of the neurone in synchronization with the recruiting responses in the parietal cortex. The grouped discharges usually preceded the respective cortical responses by several milliseconds. Numbers of the spikes in the grouped discharges increased and decreased as the recruiting responses waxed and waned on the repetitive stimulation. 3. The superficial T-C neurones also showed similar grouped discharges in synchronization with spindling-like, surface-negative cortical responses which occurred spontaneously or were evoked by single thalamic stimulation. 4. It was concluded that the superficial T-C neurons can convey impulses for recruiting responses and spindling-like responses from the thalamus directly to the cerebral cortex. They are supposed to constitute the final T-C pathway of the neuronal circuits of the recruiting system, i.e., non-specific T-C projection system.

EXPERIMENTAL STUDIES ON THE ORIGIN OF CULTIVATED RICE

1) Contributions to the origin of cultivated rice made by the author and his colleagues were briefly reviewed under several headlines.—2) Two parallel series of evolution of cultivated species, the Asian form of Oryza perennis to O. sativa and O. breviligulata to O. glaberrima, were pointed out compared.—3) In both the two series, a continuous array of intergrades between wild and cultivated species is found in a particular region. The pattern of character variations among those intermediate plants was considered as indicating the evolutionary path, and the monophyletic origin of the Indica and Japonica types of O. sativa was discussed.—4) The conditions of establishment of a weedy form of O. perennis found in India were discussed. It was noticed that cultivation by man in itself works as a selective agent for cultivated types.

Genic analysis for peroxidase isozymes and their organ specificity in Oryza perennis and O. sativa

Peroxidase zymograms of the leaf blade, leaf sheath and lemma-palea were observed in progeny of crosses between strains of Oryza perennis Moench and O. sativa L. Bands OC, 2A, and 4A were found to be specified by codominant alleles, Px1OC, Px12A, and Px14A, respectively. These alleles produced hybrid bands 1A and 3 A in their heterozygotes. Regarding band 4C specified by Px24C, (independent of Px1), it was found that a perennis strain (W120-4, derived from an Indian natural population) had the band in the leaf sheath only, while another (W120-5, from the same population) showed it in the leaf blade only. Observations of their selfed progenies and hybrids suggested that there were two independent dominant genes repressing band 4C, one (RLB4C) acting in leaf blade and the other (RLS4C) acting in leaf sheath. On this basis, the organ-specific intensity variations of the 4C band observed in four different crosses could also be explained. These genes were considered to be "regulatory genes" repressing the activity of Px24C.