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Biomedical subjects

T Nomoto

Publications and source records attributed to T Nomoto.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Analysis on deformity of disk associated with internal derangement of TMJ].

Internal derangement of temporomandibular joint has been studied mainly arthrographically about disk position, but it was reported that morphologic alterations and histo-chemical changes of disk were frequently observed in joints with internal derangement. The aim of this investigation was to study the relationship between deformity of disk and the kind of internal derangement of TMJ (anterior disk displacement with or without reduction). We analysed arthrographically the configuration of anterior displaced disk according to the criteria of Westesson. Deformity of disk was seen in 35 joints in 60 joints (58.3%) associated with anterior disk displacement with reduction, and 51 joints in 66 joints (77.3%) without reduction. Statistically significant difference existed between the distribution of disk configuration in with-reduction and without-reduction. We analysed the relationship between distribution of disk configuration and age, clicking period and locking period. In cases long suffering from clicking and locking, no-deformed disk were seen, and any certain type of deformed disk did not increase. From above results it was suggested that there was a strong relationship between distribution of disk configulation and types of anterior disk displacement (with or without reduction).

Arthrography↗
PubMed1988

Centrally administered thyrotropin-releasing hormone in the regulation of regional blood flow to brown adipose tissue in rats.

The effects of thyrotropin-releasing hormone (TRH) administered via the lateral ventricle on the blood flow to the interscapular brown adipose tissue (IBAT) was studied in urethane anaesthetized rats. TRH in i.c.v. doses of 50 or 5 micrograms/kg produced a significant and transient decrease in IBAT blood flow. The effect of 5 micrograms/kg TRH was blocked by bilateral surgical denervation. TRH caused a comparable decrease in blood flow to both the innervated pad of unilaterally denervated rats and the intact pads of non-operated rats whereas no response to TRH was observed in the denervated pad. Adrenal demedullation partly inhibited but did not completely abolish the effect of TRH on IBAT blood flow and lessened the increase in serum adrenaline caused by TRH. The effect of TRH was dose dependently suppressed by pretreatment with prazosin 15 min prior to TRH. Yohimbine did not influence the effect of TRH on IBAT blood flow. Central administration of TRH affects the regional blood flow to IBAT and appears to interfere with neural mechanisms that involve mediation by the alpha 1-adrenoceptors on the vasculature. The effect is in part due to circulating adrenaline from the adrenal medulla.

Adipose Tissue, Brown↗
PubMed1988

Effect of streptozotocin administration to pregnant mice on serum glucose, glycosylated hemoglobin and weight of organs of the mother mice and their pups.

Administration of streptozotocin (STZ, 200 mg/kg, i.p.) to pregnant mice during either the early or middle stages of pregnancy produced diabetic conditions in the mother mice. It reduced the litter size, but did not induce diabetes in the pups. The weights of the liver and kidney per unit body weight of the infants of STZ-treated mother mice were slightly larger, though not significantly, than that of infants from control mothers; however, no increase was observed in the blood glucose or glycosylated hemoglobin (HbA1) values.

Animals↗
PubMed1988

[Proconvulsant effect of morphine on seizures induced by pentylenetetrazol in the mice].

The present study was designed to investigate the proconvulsant effect of morphine (10, 30, 50 mg/kg, sc) in mice on pentylenetetrazol (PTZ)-, picrotoxin-, and bicuculline (BCC)-induced convulsions which are thought to be produced by interactions with GABAergic systems. Morphine increased the severity of seizures induced by the ip (50 mg/kg) and sc (90 mg/kg) routes of administration of PTZ. An administration of morphine caused an increased incidence of multiple seizures following both ip and sc administration of PTZ and prolonged the latency to onset of seizures induced by ip injection of PTZ. Repeated morphine administration (30, 50 mg/kg, ip x 4d) also caused an increased incidence of multiple seizures and the latency to onset of seizures by ip injection of PTZ. All these effects of morphine are naloxone-sensitive. Single morphine administration potentiated seizures induced by picrotoxin (2 mg/kg, iv) and BCC (20 mg/kg, iv). These results demonstrate that morphine has a proconvulsant effect on PTZ-induced seizures in the mouse.

Animals↗
PubMed1987

Central action of cesium chloride in streptozotocin-diabetic mice.

The changes in the pharmacological responses to cesium were examined in streptozotocin(STZ)-induced diabetic mice. An acute administration of cesium chloride (10 mEqCs+/kg IP) to non-diabetic control mice elicited increased salivation and inhibition of respiration followed by death in about half of the animals examined. These effects of cesium were diminished in STZ-diabetic mice. LD50 for acute cesium was higher in STZ-diabetic mice (14.3 mEq/kg) than non-diabetic buffer controls (11.7 mEq/kg): however, subchronic administration of cesium did not decrease the LD50 in STZ-diabetic mice. The sleeping time induced by pentobarbital was reduced in STZ-diabetic mice and the reduction of the pentobarbital-induced hypnosis was reversed by subchronic cesium pretreatment but not by acute cesium administration. Methamphetamine-induced mortality was increased in STZ-diabetic mice and acute administration of cesium decreased the toxicity in both control and diabetic mice. Inhibition of locomotor activity elicited by acute single injection of cesium chloride was observed in both STZ-diabetic and non-diabetic mice. These results indicate that responses to cesium as well as centrally-acting drugs are affected differentially in STZ-diabetic mice.

Animals↗
PubMed1987

[Changes in pentobarbital hypnosis and hepatic metabolism in streptozotocin-diabetic mice].

The present study deals with the hypnotic effect of pentobarbital (Pento) in relation to its metabolism in hepatic microsomes in streptozotocin (STZ, 170 mg/kg, i.p.) injected mice. Liver weight (mg/10 g body wt.) of STZ-treated mice was larger than that of the controls throughout the experimental period. Although the shortening of sleeping time induced by Pento (60 mg/kg, i.p.) was always observed, Pento-metabolizing enzyme activity (by the method of Kato et al., 1964) increased in mice with diabetes for 2 and 4 weeks but decreased in mice with diabetes for 8 weeks. Induction following phenobarbital (100 mg/kg, s.c.) and inhibition by SKF 525-A (10 mg/kg, i.p.) of hepatic metabolizing enzyme were found in both control and mice with diabetes for 2, 4 and 8 weeks, but these were not definitely correlated to their hepatic Pento-metabolizing enzyme activities. STZ-induced hyperglycemia and shortening of sleeping time by Pento were completely prevented by the pretreatment with nicotinamide (500 mg/kg, i.p.). NPH-insulin injection partially decreased hyperglycemia in STZ-diabetic mice, but sleeping time by Pento was not significantly affected. These results suggest that the hyposensitivity to Pento in STZ-diabetic mice is partially related to an abnormality of metabolism in liver such as the hyperglycemic state.

Animals↗
PubMed1986

Administration of ACTH to suckling rats results in hyperkinetic behavior.

The present study on ACTH-administered suckling rats was undertaken to monitor the late behavioral sequelae due to the effects of this drug. The locomotor activity of rats treated with ACTH in the suckling period increased significantly as to the gross size of movements when compared with control rats. The increase in locomotor activity was correlated with the suppression of CNPase activity. These results show that administration of ACTH during the suckling period has suppressive effects on the development of the brain and behavior, and that these effects persist for a longer period after termination of the administration of ACTH than the direct effect of the peptide on endocrine functions.

Adrenocorticotropic Hormone↗
PubMed1983

Thyrotropin releasing hormone-induced hyperthermia in mice: possible involvement of adrenal and pituitary glands.

To investigate the hyperthermic effect of thyrotropin releasing hormone (TRH) and its potentiation by exogenous catecholamines (CA), the role of the adrenal medulla and of the pituitary gland was studied in unoperated, adrenal-demedullated or hypophysectomized mice. In unoperated mice, TRH 40 mg kg-1 i.p. produced a hyperthermia which was accompanied by an increase in plasma noradrenaline (NA) and adrenaline (Ad). NA or Ad, both at a dose of 1 mg kg-1 i.p., enhanced the TRH-induced hyperthermia. Adrenal demedullation suppressed the hyperthermia and the increase of plasma CA produced by TRH but not the potentiation of this hyperthermia by exogenous CA. Hypophysectomy abolished the TRH-induced hyperthermia but not the increase of plasma CA or the potentiation of this hyperthermia by exogenous CA. These results suggest that, in mice, both the adrenal medulla and the pituitary gland play an essential role in TRH-induced hyperthermia but not in its potentiation.

Adrenal Glands↗
PubMed1982

Postnatal change in receptivity for methionine5-enkephalin in rat duodenum: transition from neurogenic to myogenic receptivity.

The study concerned the postnatal ontogenesis of the response to methionine5-enkephalin (ENK) in the duodenum of developing rats. Sustained relaxation was produced by ENK in the isolated duodenum of 8 day old rats. The response was blocked by tetrodotoxin or naloxone. The response increased by day 18, decreased thereafter and was extinguished after 40 days. On the other hand, a tetrodotoxin resistant response to ENK, transient relaxation, appeared at day 20 and was augmented thereafter. The development of neurogenic receptivity for ENK preceded the appearance of myogenic receptivity in the rat duodenum.

Aging↗
PubMed1982

Effect of intracerebroventricular administration of chlorpromazine on the serum level of free fatty acids in rats.

The effect of intracerebroventricular administration of chlorpromazine (CPZ) on the serum level of free fatty acid (FFA) was studied in rats. Injection of CPZ into the lateral ventricle caused a transient decrease in serum FFA, showing the lowest level after 30 min. This decrease in serum FFA caused by CPZ was significantly inhibited by simultaneous injection of dopamine or apomorphine, although noradrenaline and serotonin had no effect. The dopaminergic blocking agent haloperidol caused a rapid decrease in serum FFA. After central chemical sympathectomy with the intracerebroventricular injection of 6-hydroxydopamine, the response to CPZ of serum FFA was completely abolished; but after peripheral sympathectomy by i.v. injection of 6-hydroxydopamine, a partial inhibition of the action of CPZ was shown. These results suggest a possible involvement of the central dopaminergic mechanism in the decrease in serum FFA after intracerebroventricular injection of CPZ.

Animals↗
PubMed1982

Effects of nicotinamide and insulin on glycosylated hemoglobin and blood glucose in thyroidectomized streptozotocin-diabetic rats.

The present study deals with the effects of nicotinamide and insulin on glycosylated hemoglobin (HbA1) and blood glucose in thyroidectomized streptozotocin (STZ)-diabetic male rats. Nicotinamide (500 mg/kg body wt., i.p.) significantly decreased the levels of HbA1 and blood glucose in both STZ-treated (65 mg/kg body wt., i.v.) intact and STZ-treated thyroidectomized animals. Administration of NPH-insulin recovered hyperglycemia, and the increased HbA1 in thyroidectomized STZ-diabetic rats to control levels.

Animals↗
PubMed1982

[Changes in glucose metabolism and cardiovascular responses in thyroidectomized streptozotocin treated diabetic rats (author's transl)].

Two weeks after streptozotocin i.v. injection, changes in glucose metabolism, levels of serum and urinary calcium, magnesium and copper, and cardiovascular responses were investigated in thyroidectomized streptozotocin treated diabetic rats. These parameters were compared to those of intact rats. Serum and urinary calcium, magnesium and copper concentrations were not influenced by thyroidectomy. Glycosylated hemoglobin (HbA1) in thyroidectomized streptozotocin treated diabetic rats was higher than that in those which were thyroidectomized alone. In thyroidectomized rats that induction of hyperglycemia required dose of streptozotocin than for intact rats. Norepinephrine (0.3125, 0.625, 1.25 micrograms/kg i.v.)-induced pressor response and ACh (0.3125, 0.625, 1.25, 2.5 micrograms/kg i.v)-induced depressor responses were both reduced in streptozotocin treated diabetic rats. These reduced pressor and depressor responses tended to recover after thyroidectomy. These results suggest that hypothyroid states may partially improve glucose metabolism and cardiovascular responses in streptozotocin treated diabetic rats.

Acetylcholine↗
PubMed1981

Transition from neurogenic to myogenic receptivity for thyrotropin-releasing hormone (TRH) in the duodenum of the neonatal rat.

A tetrodotoxin- and hexamethonium-sensitive response to thyrotropin-releasing hormone (TRH), an in vitro contraction, first appeared in the duodenum of the 3 day old rat, was increased by day 16, decreased there-after and was extinguished after weaning. A tetrodotoxin-resistant response to TRH, a relaxation, appeared at day 13 and became distinct after weaning. The development of neurogenic receptivity for TRH precedes the appearance of myogenic receptivity in the rat duodenum.

Acetylcholine↗