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Biomedical subjects

K Toda

Publications and source records attributed to K Toda.

At least 289 records · Page 16Linked to original sources
PubMed1982

Responses of raphe magnus neurons to systemic morphine in rats.

The spontaneous firing rate of nucleus raphe magnus (NRM) neurons increased, decreased or were not altered in Wistar rats after various doses of morphine were administered intravenously. Dose-related changes were observed only in neurons which displayed increased firing frequency. Naloxone antagonized the morphine-induced effect more frequently in the excited neuron than in the inhibited one. These results suggest that morphine induced increases in discharge frequency is the more specific pharmacological effect, and that only the excited neuron might participate directly in the descending analgesic system of morphine.

Animals↗
PubMed1982

Suppression of tooth pulp evoked responses by activation of raphe-trigeminal neurons in rat.

Electrical stimulation (0.1 msec duration, 50 Hz, 1 min) applied to the nucleus raphe magnus markedly suppressed the tooth pulp evoked responses in caudal part of the spinal trigeminal nucleus but only slightly altered those in its rostral area. Raphe stimulation also greatly suppressed jaw opening reflex evoked by tooth pulp stimulation, which lasted longer than suppression of spinal trigeminal nucleus.

Animals↗
PubMed1982

Correlations between salivary protease and supragingival or subgingival calculus index.

Significant positive correlations between protease activities in saliva and supragingival/subgingival calculus indices, periodontal pocket depth, or P-M-A index were confirmed. When the partial correlation was calculated, the subgingival calculus index correlated well with the sediment protease at pH 8.5, and the supragingival calculus index showed a significant correlation with the supernate protease at pH 4.5.

Adolescent↗
PubMed1982

Threshold changes of the jaw-opening reflex by the impulses of afferent nerve fibers for conveying electroacupuncture analgesia in rats.

The effects of the conditioning electrical stimuli applied directly to the nerves (45 Hz, 0.1 ms, 15 min) innervating the meridian points of Yin-Hsiang (infraorbital nerve), Ho-Ku (radial nerve) and Zu-Sanli (common peroneal nerve) on the pulp-evoked jaw-opening reflex were investigated in the Wistar albino rats. The threshold change of the digastric electromyogram activity in the reflex was monitored during and after the conditioning stimulation. There was a gradual change in the threshold and the effect remained for several minutes after the cessation of the conditioning stimulation. In case of stimulating each ipsilateral nerve, the effective degree was 210 to 260% of the control. On the other hand, when each contralateral nerve was stimulated, the degree was 170 to 200% of the control. The reflex was also evoked by the low intensity of the direct infraorbital nerve stimulation. The threshold value of this reflex was not altered by the conditioning stimulation of each nerve.

Acupuncture Therapy↗
PubMed1982

Topical methoxsalen followed immediately by long-wave UV irradiation. A preliminary report on the treatment of psoriasis.

In the treatment of psoriasis with topically applied methoxsalen, the patient is exposed to long-wave UV (UV-A) energy two hours after the application of methoxsalen. Using the guinea pig as an experimental model, we found that UV-A irradiation given immediately after the topical application of methoxsalen resulted in the notable suppression of tritiated thymidine incorporation into epidermal basal cells. This finding suggests that the rate of suppression of epidermal DNA synthesis by PUVA (methoxsalen plus UV-A light) may not correlate with the interval between methoxsalen application and UV-A irradiation. This modified method of PUVA therapy (immediate irradiation) was successfully used in the treatment of psoriasis.

Administration, Topical↗
PubMed1981

Jaw opening reflex affected by electroacupuncture in rat.

In rats, the jaw opening reflex to tooth pulp stimulation was suppressed, but that to lower lip stimulation was scarcely affected by electroacupuncture stimulation of the forefoot. After transection of the spinal trigeminal nucleus at the obex level, the magnitude of the reflex to tooth pulp stimulation was greatly decreased and electroacupuncture was less effective on the pulp-evoked reflex. By contrast, the reflex activity to lower lip stimulation was not altered after the transection. The present study suggests that the site of action of electroacupuncture on the jaw opening reflex is in the caudal part of the spinal trigeminal nucleus and that pulp evoked jaw opening reflex is a presumed nocifensive response.

Acupuncture Therapy↗
PubMed1981

Inhibitory actions produced by local electrical stimulation in the caudal spinal trigeminal nucleus in rat.

Inhibitory actions induced by local electrical stimulation (LES) on the tooth pulpal afferent activities were investigated in the caudal part of the rat spinal trigeminal nucleus. For the LES, ipsilateral Yin-Hsiang (intrasegmental point) or Ho-Ku (extrasegmental point) was used as a cathodal point which was stimulated electrically by a single pulse of 0.1 msec in duration or by 0.1 msec-pulse train at 45 Hz for 15 min. We found at least three types of inhibitions in the caudal trigeminal nucleus: Type I--this inhibition is the most forceful, caused by naloxone-reversible endogenous opiate system with a slow onset and prolonged aftereffect. This inhibition is presumably postsynaptic action. Type II--this is evoked by postsynaptical acting inhibition and begins within milliseconds after the stimulus is applied. Type III--this inhibition is elicited by presynaptic action and also begins within milliseconds after the onset of the stimulation. Type I and II inhibitions are evoked by stimulating either intra- or extrasegmental LES points, however, Type III is produced by stimulation of intrasegmental and rarely provoked by extrasegmental point stimulation. Naloxone failed to reverse Type II and III inhibitions. During LES, Type I to III inhibitions co-work for producing the suppressive effect and after the cessation of its stimulation, only Type I inhibition produces the so-called aftereffect of the LES.

Afferent Pathways↗
PubMed1981

Developmentally regulated glycoprotein alterations in Dictyostelium discoideum.

We have studied the changes in glycoprotein patterns on the surface of Dictyostelium discoideum cells during development on a membrane filter and in suspension culture. Cell-surface carbohydrates were detected by a periodate-[3H]borohydride method. The appearance and the increase of some glycoproteins during the early developmental stage on a membrane filter were induced 6 h after the onset of starvation. In suspension culture the same proteins appeared about 2 h earlier and less copies per cell were made. Some glycoproteins present in growth-phase cells, especially with high molecular weights, partially disappear during development on a membrane filter. However, the latter changes were not observed in suspension culture. Pulses of cAMP, which generally accelerate cell development, induced only the appearance of one glycoprotein. We conclude that the changes in patterns of plasma membrane glycoproteins during early development are regulated by several factors; starvation, pulses of cAMP, cell-cell contact and transfer onto a membrane filter.

Cell Membrane↗