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Biomedical subjects

Y Ninomiya

Publications and source records attributed to Y Ninomiya.

At least 307 records · Page 17Linked to original sources
PubMed1982

Responsiveness of dog thalamic neurons to taste stimulation of various tongue regions.

Receptive fields of single thalamic taste neurons in dogs were studied by examining responses to stimuli representing the four basic taste qualities applied to five different regions on the tongue surface. Twenty single thalamic units responded to taste stimulation of the tongue ipsilateral to the recording site were classified into three types according to characteristics of their receptive fields. In 11 out of 20 units, the location and the size of the receptive field and the most sensitive region in the receptive field did not vary among their effective taste stimuli (type A units). In 5 units, the location and the size of the receptive field varied with taste stimulus, although the most sensitive region was common to the stimuli (type B units). In the remaining 4 units, the most sensitive region varied with taste stimulus (type C units).

Afferent Pathways↗
PubMed1981

Dynamic-static sensitivity of rat chorda tympani fibers to anodal current applied to the tongue.

Responses of rat single chorda tympani fibers to anodal current of varying rise rates and current intensities applied to the tongue were examined. Thirteen out of fifteen chorda tympani fibers were sensitive to both rate of current rise and current intensity. However, sensitivities to these two stimulus parameters were different among 13 fibers. The remaining two fibers were not sensitive to the rate of current rise, but sensitive to current intensity. It was suggested that sensitivity to the rate of current rise was independent from that to current intensity.

Animals↗
PubMed1981

Localization of carbonic anhydrase in the rat lung.

The localization of carbonic anhydrase in the rat lung has been demonstrated, at light and electron microscopic levels, by the cobalt bicarbonate histochemical method of Hansson. Focal deposits of the cobalt sulfide reaction product were found not only in the capillary endothelium of the alveolar walls, but also in the small and large alveolar cells. The histochemical reaction was abolished by two potent inhibitors, acetazolamide (10(-5) to 10(-6) M) and KCNO (5 x 10(-3) to 10 x 10(-3) M). Physiological assay with Maren's method indicated that values for carbonic anhydrase activity in rat lung are 4.4 +/- 0.8 UA/mg of protein, 25.0 +/- 5.5 UA/mg of nitrogen, and 369 +/- 86 UA/g of wet weight. In addition, it was calculated that after fixation in glutaraldehyde-formaldehyde-picric acid about 9% activity is retained.

Acetazolamide↗
PubMed1981

Active synthesis of glycosaminoglycans by liver parenchymal cell in primary culture.

Rat liver parenchymal cells were evaluated after 2 days of primary culture for their ability to synthesize and accumulate heparan sulfate as the major component and low-sulfated chondroitin sulfate, dermatan sulfate, chondroitin sulfate and hyaluronic acid as the minor ones. The newly synthesized glycosaminoglycans secreted into the medium were different from those remaining with and/or the cell layer. Low-sulfated chondroitin 4-sulfate, a major glycosaminoglycan in blood, was synthesized in the order of 320 microgram/liver per day, more than 90% of which was secreted into the medium with 16 h and 40% of the glycan secreted was degraded during that time. On the other hand, heparan sulfate, the major glycosaminoglycan synthesized by the parenchymal cells, was mainly distributed in the cell layer. After 8 days of culture, the synthesis of glycosaminoglycans by the cells increased markedly, especially dermatan sulfate, chondroitin sulfate, chondroitin sulfate and hyaluronic acid.

Animals↗
PubMed1981

Responses of rat chorda tympani fibers to electrical stimulation of the tongue.

Responses of rat chorda tympani fibers to stimulations of the tongue with linearly rising anodal currents of varying rise rates and intensities, cathodal currents and chemical solutions representing the four basic taste qualities were obtained. Single fibers were classified into four types according to their response patterns to anodal and cathodal current stimulations of the tongue. Type A1 fibers responded only to an anodal current with both transient and steady response phases. Type A2 fibers responded only to an anodal current with only a steady response phase. Type B fibers responded to both anodal and cathodal currents. Type C fibers responded only to a cathodal current. Sensitivity to the rate f anodal current rise varied widely among individual chorda tympani fibers. The NaCl-sensitive fibers were most sensitive, the tartaric acid-sensitive fibers next, and the sucrose-sensitive fibers least. Fibers responding to cathodal current were sensitive to quinine hydrochloride. Fibers which showed rhythmic bursts of discharges in response to chemical stimuli also gave a similar discharge pattern in response to electrical stimulation.

Animals↗
PubMed1981

Role of ions in generation of taste nerve responses to electrical tongue stimulation in rats.

The role of ions in the generation of taste nerve responses to electric currents was studied by examining integrated responses and single fiber discharges of the chorda tympani nerve to chemical and electrical stimulations of the tongue in rats. Integrated chorda tympani responses to anodal currents were suppressed after cessation of the blood flow to the tongue and on application of FeCl3 to the tongue surface. These findings indicate that electric currents do not stimulate the nerve directly but activate taste cells to evoke neural discharges. Magnitude of the integrated response to anodal current decreased with a decrease in concentration and with an increase in flow rate of the bathing solution applied over the tongue during electrical stimulation. All the chorda tympani fibers responsive to a certain electrolyte responded to anodal or cathodal current in the presence of the same electrolyte at its subliminal concentration in the flow chamber. However, there were a few fibers which did not respond to a few electrolytes, but responded to currents in the presence of either one of the electrolytes even at their much lower concentrations. Across-fiber correlations between the responses to chemical stimuli and anodal currents in the presence of the chemical solutions in the flow chamber indicated that responsiveness to anodal current was not always dependent on species of cation in the bathing solution. From these findings, we assume that the response to electric current is due to the effect of electrophoretically carried ions on not only specific but also non-specific receptor mechanisms for the ions.

Action Potentials↗
PubMed1980

Glycosaminoglycan synthesis by liver parenchymal cell clones in culture and its change with transformation.

Albumin-producing rat liver parenchymal cell clones (BB and BC) and their subclones in the confluent culture synthesized heparan sulfate as the major component and dermatan sulfate, chondroitin sulfate and hyaluronic acid as the minor ones. Their relative contents were similar to those present in the rat liver. Analyses of glycosaminoglycans synthesized by subclone cells (BB1S) at various cell densities, cell growth phases and passage levels have shown that relative content of heparan sulfate remained constant, suggesting that the epithelial cell possesses a stable heparan sulfate-producing capacity. On the other hand, the level of hyaluronic acid production was high at low cell density, though it remained constant during cell proliferation. Chemically transformed rat liver parenchymal cells (M) produced relatively higher amount of chondroitin sulfate than non-transformed cells did, as observed with 4-nitroquinoline-1-oxide-transformed 3T3 cells, compared to 3T3 714 cells. The results obtained on this study strongly suggest that the liver parenchymal cells synthesize a major part of the glycosaminoglycans of the liver and chondroitin sulfate production is closely related to cellular proliferations.

Animals↗
PubMed1980

Biosynthesis of interstitial types of collagen by albumin-producing rat liver parenchymal cell (hepatocyte) clones in culture.

We have analyzed collagenous components produced by an albumin-producing rat liver parenchymal cell clone (BB) in culture. The cells secreted over 90% of the [3H]proline-labeled collagenous components into the medium after 18 h of incubation in vitro. Analysis of the components by sodium dodecyl sulfate-polyacrylamide gell electrophoresis and by carboxymethylcellulose chromatography of cyanogen bromide peptides after separation of individual collagen chains showed that the cells produced type I, type I trimer, and type II collagens in the ration 59:29:4. These components account for over 90% of the collagen isolated. Type I and type I trimer collagens were present in both the medium and cell layer fractions, but type III collagen was found solely in the medium. The cells also produced other minor collagenous components, one of which was quite similar to type V collagen. Analysis of collagen components produced by another liver parenchymal cell clone (BC) and by three subclones derived from BB cells showed that these cloned cells synthesized similar types of collagen. These results support the idea that parenchymal cells play an essential role in the heaptic connective tissue metabolism under normal and pathological conditions.

Animals↗
PubMed1979

Decline and disappearance of taste response after interruption of the chorda tympani proper nerve of the rat.

The response amplitude in the chorda tympani proper nerve of rats to taste stimulation has been studied at different times after interruption of the nerve in the middle ear. The results show that the reponse in the nerve declined and disappeared completely within 15 h after the nerve was interrupted. As a first sign of deteriorating function a stage of hypersensitivity was observed. Results obtained during applications of local anesthetic or colchicine and section at different distances from the tongue indicate that the decreased response was the result of an interruption of axoplasmic flow from the nerve cell bodies in the geniculate ganglion to the taste buds.

Anesthesia, General↗
PubMed1979

Modulation of glycosaminoglycan synthesis during cell growth as observed in an embryonic chick tendon cell culture.

Glycosaminoglycan synthesis during cell growth has been studied in terms of unit cell numbers, using 16-day-old embryonic chick tendon cell cultures. Hyaluronic acid production was found to be inversely proportional to the cell density, while the levels of sulfated-glycosaminoglycan synthesis remained constant. On the other hand, hyaluronic acid production remained constant during cell proliferation, though chondroitin sulfate synthesis increased rapidly during an actively growing phase of the cultured cells, and dermatan sulfate and heparan sulfate syntheses increased gradually.

Animals↗