Impairment of gastric accommodation induced by water-avoidance stress is mediated by 5-HT2B receptors.

BACKGROUND: Psychological stress has been shown to impair gastric accommodation (GA), but its mechanism has not been elucidated. This study was conducted to clarify the role of 5-HT2B receptors in a guinea pig model of stress-induced impairment of GA. METHODS: Gastric accommodation was evaluated by measuring the intrabag pressure in the proximal stomach after administration of a liquid meal. The guinea pigs were subjected to water-avoidance stress. The role of 5-HT2B receptors in impairment of GA was investigated by administering a 5-HT2B receptor agonist (BW723C86) or antagonist (SB215505), the traditional Japanese medicine rikkunshito (RKT), a muscarinic M3 receptor antagonist (1,1-dimethyl-4-diphenylacetoxypiperidium iodide [4-DAMP]), or a nitric oxide synthase inhibitor (Nω -nitro-L-arginine [L-NNA]). KEY RESULTS: In normal animals, liquid meal-induced GA was inhibited by BW723C86, but was not affected by SB215505. The inhibition of GA by BW723C86 was reversed by co-administration of 4-DAMP. Compared to normal animals, GA in stressed animals was significantly inhibited. SB215505 and RKT significantly suppressed stress-induced impairment of GA. After meal administration, the level of cyclic guanosine monophosphate in gastric fundus tissue increased by approximately twofold in normal animals, but did not change in stressed animals. The inhibition of GA by L-NNA was suppressed by SB215505 or RKT. At a dose that did not affect GA in normal animals, BW723C86 exacerbated the impairment of GA in stressed animals. CONCLUSIONS AND INFERENCES: Stress-induced impairment of GA may be mediated by an increased responsiveness of 5-HT2B receptors, and activation of the 5-HT2B receptor signaling pathway may have an inhibitory effect on nitric oxide function.

Effect of rikkunshito on the expression of substance P and CGRP in dorsal root ganglion neurons and voluntary movement in rats with experimental reflux esophagitis.

BACKGROUND: While there are reports that the herbal medicine rikkunshito (RKT) relieves upper gastrointestinal disease symptoms, the effect of RKT on primary afferent neurons is unknown. METHODS: A model of reflux esophagitis (RE) was implemented using male Wistar rats aged 6-7 weeks. Ten days after surgery, the total area of esophageal mucosal erosion sites was determined. Th8-10 dorsal root ganglia (DRG) were dissected out and the expression of substance P (SP), calcitonin gene-related peptide (CGRP), and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) was determined in DRG using immunohistochemistry. RKT (0.6%/WV) or omeprazole (OME) (10 mg/kg) was administered for 10 days beginning on the day after surgery. Voluntary movement was measured with an infrared sensor for 22 h each day. KEY RESULTS: RE rats showed esophageal mucosal erosion and significantly increased number of SP/CGRP- and p-ERK1/2-immunoreactive neurons in DRG. Treatment with OME improved the size of erosive lesions in the esophageal mucosa of RE rats, while RKT did not. Treatment with RKT or OME significantly reduced the expression of SP/CGRP and p-ERK1/2 in DRG, and significantly increased voluntary movement in RE rats. CONCLUSIONS & INFERENCES: RKT inhibited the activation of ERK1/2 and decreased the expression of SP and CGRP in DRG of RE rats, which may be associated with the observed amelioration of voluntary movement.

Design of ridge filters for spread-out Bragg peaks with Monte Carlo simulation in carbon ion therapy.

Spread-out Bragg peaks made by ridge filters or wheel range modulators are used in charged particle therapy with passive methods to achieve uniform biological responses in irradiated tumors. Following the biological responses needed to design the ridge filters, which were developed at the National Institute of Radiological Sciences in Japan, new ridge filters were designed using recent developments in heavy-ion reactions and dosimetry. The Monte Carlo code of Geant4 was used to calculate the qualities of carbon ion beams in a water phantom. The results obtained from the simulation were corrected so that they agreed with the measurements of depth dose distributions. The calculations of biological responses to fragments other than carbon ions were assumed to be for helium ions. The measured dose distributions with the designed ridge filters were compared to the calculated distributions. A beam modifying system using this adaptable method was successively applied to carbon ion therapy at Gunma University.

Yokukansan inhibits morphine tolerance and physical dependence in mice: the role of α2A-adrenoceptor.

Yokukansan (YKS) is a traditional Japanese medicine consisting of seven medicinal herbs that is used for the treatment of neurosis, insomnia, and the behavioral/psychological symptoms of dementia. This study examined the effects of YKS on morphine tolerance and physical dependence in mice. Daily oral administration of YKS (0.5 or 1.0 g/kg) for 3 weeks significantly attenuated morphine tolerance and naloxone-precipitated morphine withdrawal signs (jumps and body weight loss) without affecting the analgesic effect of morphine. The inhibitory effect of YKS on withdrawal jumps in morphine-dependent mice was blocked by a single pretreatment with an α(2)-adrenoceptor antagonist, yohimbine, but not by an α(1)-adrenoceptor antagonist, prazosin. A similar inhibitory effect on withdrawal jumps was observed by repeated administration of yohimbine. The membrane expression of α(2A)-adrenoceptors in the pons/medulla was decreased in morphine withdrawn animals; this reduction was prevented by repeated administration of YKS or yohimbine. Competitive radioligand and [(35)S]guanosine-5'-O-(3-thiotriphosphate) binding assays revealed that YKS and its constituent herbs, Glycyrrhiza (GR) and Uncaria hook (UH), had specific binding affinity for and antagonist activity against the α(2A)-adrenoceptor. Certain chemical constituents, including GR -derived glycyrrhizin and its metabolite, 18ß-glycyrrhetinic acid, and UH-derived geissoschizine methyl ether (GME), shared such activities. Repeated administration of GR, UH, glycyrrhizin or GME significantly inhibited morphine withdrawal signs. These results suggest that YKS and its active constituents inhibit morphine tolerance and physical dependence, and that the latter is due at least in part to the prevention of the decreased membrane expression of the α(2A)-adrenoceptor in the brainstem by its prolonged blockade.

Geissoschizine methyl ether, an alkaloid in Uncaria hook, is a potent serotonin 1A receptor agonist and candidate for amelioration of aggressiveness and sociality by yokukansan.

Yokukansan (YKS), a traditional Japanese medicine, is composed of seven kinds of dried herbs. It is widely prescribed in clinical situation for treating psychiatric disorders such as aggressiveness in patients with dementia. We previously demonstrated that YKS and Uncaria hook (UH), which is a constituent herb of YKS, had a partial agonistic effect to 5-HT(1A) receptors in vitro. However, it has still been unclear whether this in vitro effect is reflected in in vivo, and what the active ingredients are. The purpose of the present study is to find the active ingredient in YKS and to demonstrate the effect in in vivo. In the present study, we first studied the effect of YKS and UH on aggressiveness and sociality in socially isolated mice. YKS and UH ameliorated the isolation-induced increased aggressiveness and decreased sociality, and these ameliorative effects were counteracted by coadministration of 5-HT(1A) receptor antagonist WAY-100635, or disappeared by eliminating UH from YKS. These results suggest that the effect of YKS is mainly attributed to UH, and the active ingredient is contained in UH. To find the candidate ingredients, we examined competitive binding assay and [(35)S] guanosine 5'-O-(3-thiotriphosphate) (GTPγS) binding assay of seven major alkaloids in UH using Chinese hamster ovary cells expressing 5-HT(1A) receptors artificially. Only geissoschizine methyl ether (GM) among seven alkaloids potently bound to 5-HT(1A) receptors and acted as a partial agonist. This in vitro result on GM was further demonstrated in the socially isolated mice. As did YKS and UH, GM ameliorated the isolation-induced increased aggressiveness and decreased sociality, and the effect was counteracted by coadministration of WAY-100635. These lines of results suggest that GM in UH is potent 5-HT(1A) receptor agonist and a candidate for pharmacological effect of YKS on aggressiveness and sociality in socially isolated mice.

Yokukansan, a traditional Japanese medicine, ameliorates memory disturbance and abnormal social interaction with anti-aggregation effect of cerebral amyloid ß proteins in amyloid precursor protein transgenic mice.

The deposition of amyloid ß protein (Aß) is a consistent pathological hallmark of Alzheimer's disease (AD) brains. Therefore, inhibition of Aß aggregation in the brain is an attractive therapeutic and preventive strategy in the development of disease-modifying drugs for AD. An in vitro study demonstrated that yokukansan (YKS), a traditional Japanese medicine, inhibited Aß aggregation in a concentration-dependent manner. An in vivo study demonstrated that YKS and Uncaria hook (UH), a constituent of YKS, prevented the accumulation of cerebral Aß. YKS also improved the memory disturbance and abnormal social interaction such as increased aggressive behavior and decreased social behavior in amyloid precursor protein transgenic mice. These results suggest that YKS is likely to be a potent and novel therapeutic agent to prevent and/or treat AD, and that this may be attributed to UH.

Induction of DNA DSB and its rejoining in clamped and non-clamped tumours after exposure to carbon ion beams in comparison to X rays.

We studied double-strand breaks (DSB) induction and rejoining in clamped and non-clamped transplanted tumours in mice leg after exposure to 80 keV µm(-1) carbon ions and X rays. The yields of DSB in the tumours were analysed by a static-field gel electrophoresis. The OER of DSB after X rays was 1.68±0.31, and this value was not changed after 1 h rejoining time (1.40±0.26). These damages in oxygenated conditions were rejoined 60-70% within 1 h in situ. No difference was found between the exposure to X rays and carbon ions for the induction and rejoining of DSB. Thus, the values of OER and rejoined fraction after exposure to carbon ions were similar to those after X rays, and the calculated relative biological effectivenesses of carbon ion were around 1 under both oxygen conditions. The yields of DSB in vivo depend on exposure doses, oxygen conditions and rejoining time, but not on the types of radiation quality.

Analysis of cell-survival fractions for heavy-ion irradiations based on microdosimetric kinetic model implemented in the particle and heavy ion transport code system.

It is considered that the linear energy transfer (LET) may not be the ideal index for expressing the relative biological effectiveness (RBE) of cell killing for heavy-ion irradiation, as the ion-species dependencies have clearly been observed in the relation between LET and RBE derived from cell-survival fraction data. The previously measured survival fractions of four cell lines irradiated by various ion species, employing the saturation-corrected dose-mean lineal energy, y*, instead of LET as the index of the RBE were therefore re-analysed. In the analysis, the initial slopes of the survival fractions, the so-called α-parameter in the linear-quadratic model, were plotted as a function of y*, which was calculated by the microdosimetric kinetic (MK) model implemented in the Particle and Heavy Ion Transport code System. It was found from the analysis that the ion-species dependencies observed in the relations between α and LET disappeared from those between α and y*, and their relations can be well reproduced by a simple equation derived from the MK model. These results clearly indicate the suitability of y* to be used in the estimation of the RBE of cell killing for heavy-ion irradiations, which is of great importance in the treatment planning of charged-particle therapy.

Potentiation of ghrelin signaling attenuates cancer anorexia-cachexia and prolongs survival.

Cancer anorexia-cachexia syndrome is characterized by decreased food intake, weight loss, muscle tissue wasting and psychological distress, and this syndrome is a major source of increased morbidity and mortality in cancer patients. This study aimed to clarify the gut-brain peptides involved in the pathogenesis of the syndrome and determine effective treatment for cancer anorexia-cachexia. We show that both ghrelin insufficiency and resistance were observed in tumor-bearing rats. Corticotropin-releasing factor (CRF) decreased the plasma level of acyl ghrelin, and its receptor antagonist, α-helical CRF, increased food intake of these rats. The serotonin 2c receptor (5-HT2cR) antagonist SB242084 decreased hypothalamic CRF level and improved anorexia, gastrointestinal (GI) dysmotility and body weight loss. The ghrelin receptor antagonist (D-Lys3)-GHRP-6 worsened anorexia and hastened death in tumor-bearing rats. Ghrelin attenuated anorexia-cachexia in the short term, but failed to prolong survival, as did SB242084 administration. In addition, the herbal medicine rikkunshito improved anorexia, GI dysmotility, muscle wasting, and anxiety-related behavior and prolonged survival in animals and patients with cancer. The appetite-stimulating effect of rikkunshito was blocked by (D-Lys3)-GHRP-6. Active components of rikkunshito, hesperidin and atractylodin, potentiated ghrelin secretion and receptor signaling, respectively, and atractylodin prolonged survival in tumor-bearing rats. Our study demonstrates that the integrated mechanism underlying cancer anorexia-cachexia involves lowered ghrelin signaling due to excessive hypothalamic interactions of 5-HT with CRF through the 5-HT2cR. Potentiation of ghrelin receptor signaling may be an attractive treatment for anorexia, muscle wasting and prolong survival in patients with cancer anorexia-cachexia.

Neuroprotective effects of yokukansan, a traditional Japanese medicine, on glutamate-mediated excitotoxicity in cultured cells.

To clarify the mechanism of yokukansan (TJ-54), a traditional Japanese medicine, against glutamate-mediated excitotoxicity, the effects of TJ-54 on glutamate uptake function were first examined using cultured rat cortical astrocytes. Under thiamine-deficient conditions, the uptake of glutamate into astrocytes, and the levels of proteins and mRNA expressions of glutamate aspartate transporter of astrocytes significantly decreased. These decreases were ameliorated in a dose-dependent manner by treatment with TJ-54 (100-700 microg/ml). The improvement of glutamate uptake with TJ-54 was completely blocked by the glutamate transporter inhibitor DL-threo-beta-hydroxyaspartic acid. Effects of TJ-54 on glutamate-induced neuronal death were next examined by using cultured PC12 cells as a model for neurons. Addition of 17.5 mM glutamate to the culture medium induced an approximately 50% cell death, as evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. TJ-54 (1-1000 microg/ml) inhibited the cell death in a dose-dependent manner. Furthermore, competitive binding assays to glutamate receptors showed that TJ-54 bound potently to N-methyl-D-aspartate receptors, in particular, to its glutamate and glycine recognition sites. These results suggest that TJ-54 may exert a neuroprotective effect against glutamate-induced excitotoxicity not only by amelioration of dysfunction of astrocytes but also by direct protection of neuronal cells.

Field size effect of radiation quality in carbon therapy using passive method.

The authors have investigated the dependency of radiation quality and absorbed dose on radiation field size in therapeutic carbon beams. The field size of the broad beam, formed using the passive technique, was controlled from 20 to 100 mm per side with a multileaf collimator. The absorbed dose and radiation quality on the beam center were evaluated at several depths in a water phantom using microdosimetric technique in experiments and Monte Carlo simulations. With an increase in the field size, the radiation quality was reduced, although the absorbed dose grew at the center of the field. This indicates that the dose and radiation quality at the center of the broad beam are influenced by particles from the off-center region via large-angle scattering and that such particles have relatively low radiation quality and mainly consist of fragment particles. Because such a tendency appeared to be more remarkable in the deeper region of the water phantom, it is likely that fragment particles that are born in a water phantom have a marked role in determining the field size effect.

Early detection of the Limulus amebocyte lysate reaction evoked by endotoxins.

The gelation of Limulus amebocyte lysate (LAL) evoked by bacterial endotoxins can be detected earlier than with usual methods by using laser scattering photometry to recognize the formation of small particles of clotted enzyme produced when the reaction mixture is agitated. The appearance of these small particles means that the influence of endotoxins has stimulated activation of the clotting enzyme across the LAL cascade, and the timing of their appearance is related to endotoxin concentration. This new method can be used for quick and sensitive endotoxin assay. The average endotoxin level of healthy volunteers was assayed to be 0.0738 pg/ml [0.0312-0.3445 pg/ml] (n = 11) within 70 min from the start of the assay.

The preventive effect of Daikenchuto on postoperative adhesion-induced intestinal obstruction in rats.

The present study investigated the effect of Daikenchuto (DKT) on postoperative intestinal adhesion in rats. We evaluated the effects of DKT, constituent medical herbs and active compounds on talc-induced intestinal adhesion in rats and DKT-induced contractions using isolated guinea pig ileum. DKT significantly prevented adhesion formation, and this action was inhibited by pretreatment with atropine or ruthenium red. The constituent medical herbs, Zanthoxylum Fruit and Maltose Syrup Powder significantly prevented adhesion formation. Moreover, hydroxy sanshool (HS) prevented adhesion formation, and this action was inhibited by pretreatment with ruthenium red. In contrast, DKT-induced contractions were inhibited by tetrodotoxin, atropine, and capsazepine. These results suggested that DKT had a preventive action on postoperative adhesive intestinal obstruction, and that this action was mediated by sensory and cholinergic nerves. Furthermore, HS was found to be one of the active compound of DKT, and its action was mediated by sensory nerves.

Effects of the Japanese herbal medicine Keishi-bukuryo-gan and 17beta-estradiol on calcitonin gene-related peptide-induced elevation of skin temperature in ovariectomized rats.

The effects of a Japanese herbal medicine, Keishi-bukuryo-gan, and 17beta-estradiol on calcitonin gene-related peptide (CGRP)-induced elevation of skin temperature were investigated in ovariectomized (OVX) rats. Ovariectomy not only potentiated CGRP-induced elevation of skin temperature and arterial vasorelaxation but also induced a lower concentration of endogenous CGRP in plasma and up-regulation of arterial CGRP receptors, suggesting that lowered CGRP in plasma due to ovarian hormone deficiency increases the number of CGRP receptors and consequently amplifies the stimulatory effects of CGRP to elevate skin temperature. Oral Keishi-bukuryo-gan (100-1000 mg/kg, once a day for 7 days) restored a series of CGRP-related responses observed in OVX rats by normalizing plasma CGRP levels in a dose-dependent manner as effectively as s.c. injection. 17Beta-estradiol (0.010 mg/kg, once a day for 7 days). However, Keishi-bukuryo-gan did not affect the lower concentration of plasma estradiol and the decreased uterine weight due to ovariectomy, although the hormone replacement of 17beta-estradiol restored them. These results suggest that Keishi-bukuryo-gan, which does not confer estrogen activity on plasma, may be useful for the treatment of hot flashes in patients for whom estrogen replacement therapy is contraindicated, as well as menopausal women.

Dai-kenchu-to enhances accelerated small intestinal movement.

The present study was conducted to clarify the effects of Dai-kenchu-to on accelerated small intestinal movement. We evaluated the effects of Dai-kenchu-to and its constituent herbs (dried ginger root, ginseng, zanthoxylum fruit, and malt sugar) on carbachol-accelerated mouse small intestinal transit, and contractions induced by low-frequency electrostimulation (ESC), KCl, or acetylcholine (ACh) using isolated guinea pig ileum. Dai-kenchu-to (10-300 mg/kg, p.o.) significantly improved carbachol-accelerated small intestinal transit in a dose-dependent manner. Using a concentration with the compounded rate for Dai-kenchu-to 300 mg/kg, carbachol-accelerated small intestinal transit was also significantly improved with a single dose of dried ginger root or ginseng. At a concentration of 3 x 10(-5) g/ml or less, Dai-kenchu-to, dried ginger root, and ginseng all inhibited ESC but not KCl- or ACh-induced contractions. However, at a higher concentration of Dai-kenchu-to (10(-4) g/ml) or zanthoxylum fruit (10(-5) g/ml or more) the ESC were enhanced. Both Dai-kenchu-to and dried ginger root at 10(-3) g/ml remarkably inhibited the KCl-induced contractions. These results indicate that Dai-kenchu-to improves accelerated small intestinal movement and that dried ginger root and ginseng may be involved in this effect. It is also thought that the mechanisms mainly involve the direct inhibition of smooth muscle but with a contribution from neural inhibition.

[The influence of septal perforation on measurement by acoustic rhinometry].

The influence of septal perforation on results of acoustic rhinometry was studied using cases of septal perforation and a human-nose model. Acoustic rhinometry was conducted before and after closing the perforation (average 16 mm in diameter, 23 mm from the nostril) by thin cotton patches in 33 cases (19 men and 14 women). The decrease in cross-sectional area and volume after closure was statistically significant. A human-nose model with septal holes ranging from 5, 10, 15, to 20 mm and locations ranging from 20, 40, to 50 mm from the nostril was studied by acoustic rhinometry. Our results suggest that the effect of perforations on the measurement is much greater in anterior perforations than in posterior perforations.

[Anterior turbinectomy: experimental and clinical study].

INTRODUCTION: Minimal cross-sectional areas situated at the anterior end of the inferior turbinate have the most influence on nasal patency. To improve persistent nasal obstruction, 2 types of inferior turbinectomies--conventional complete resection including the anterior and posterior mucosa and anterior resection of the anterior mucosa--were conducted and preoperative and postoperative nasal patency and stuffy sensation were compared and analyze. OBJECTS AND METHODS: Cases undergoing 2 types of turbinectomies between July 1997 and March 2000 numbered 63--conventional in 32 (64 sides) and anterior in 31 (62 sides). Anterior, posterior, and total nasal volume and minimal cross-sectional area were evaluated pre- and postoperatively using an acoustic rhinometer. The stuffy sensation was similarly evaluated by the visual analog scale (VAS). RESULTS: All nasal volumes showed postoperative increase under conventional treatments. Anterior and posterior volumes significantly increased under anterior treatment. Comparing the results of postoperative volume posterior volume was significantly larger under conventional treatment than under anterior treatment. Stuffy sensation significantly improved by VAS in both types of turbinectomy, with no significant difference between them. CONCLUSION: Anterior treatment to solely increase nasal volume at the minimal cross sectional area showed equal postoperative improvement in VAS under conventional treatment.

Effects of Dai-kenchu-to, a herbal medicine, on uterine and intestinal motility.

The effects of both Dai-kenchu-to and PGF(2alpha) on intestinal and uterine motility were studied in anaesthetized rabbits with force transducers implanted in the jejunum, ileum and uterus. A single intraduodenal administration of Dai-kenchu-to (300 mg/kg) enhanced the intestinal motility but not the uterine motility. However, intravenous administration of PGF(2alpha) (20 microg/kg) enhanced both intestinal and uterine motility. The effects of Dai-kenchu-to on the spontaneous contraction and contractile response of the isolated rat uterine strips to oxytocin, PGF(2alpha) or ACh were also studied. Oral administration of Dai-kenchu-to at 300 mg/kg for one week had no effect on either the spontaneous contraction or the contractile response of the uterus. These results indicate that Dai-kenchu-to may exert stimulatory effects on intestinal motility, as PGF(2alpha), but has no effect on the uterine motility, suggesting a selective effect on the gastrointestinal tract. Hence, Dai-kenchu-to may be safer than PGF(2alpha) in the treatment of postoperative adhesive ileus in women. However, more studies are needed to determine whether Dai-kenchu-to could be administered to pregnant women.

Mechanisms for contractile effect of Dai-kenchu-to in isolated guinea pig ileum.

The mechanisms by which Dai-kenchu-to (TJ-100), a kampo medicine, enhances gastrointestinal motility was investigated using isolated guinea pig ileum. TJ-100 induced contractions accompanied by autonomous contraction at a concentration of more than 3 x 10(-4) g/ml in a dose-related manner. The TJ-100-induced ileal contraction was suppressed by atropine and tetrodotoxin, but not by hexamethonium. This effect was partially suppressed in the presence of high concentrations of ICS 205-930, a serotonin 4 (5-HT4) receptor antagonist. In addition, TJ-100 showed an acetylcholine (ACh)-releasing action in the smooth muscle tissues of ileum. These results suggest that contractile response induced by TJ-100 is partially mediated by ACh released from the cholinergic nerve endings and that 5-HT4 receptors would be involved in the effect of TJ-100.