Endothelin-1 induces vasoconstriction through two functionally distinct pathways in porcine coronary artery: contribution of phosphoinositide turnover

Endothelin-1 (ET1)-induced contraction of isolated porcine coronary artery strips was previously reported to be mainly dependent on extracellular Ca2+. However, even in a Ca2+-free, EGTA-containing solution relatively high concentrations of ET1 induced a weak vasoconstriction, which was markedly but not completely inhibited by pretreatment with caffeine. Over similar dose ranges, ET1 stimulated the production of inositol phosphates in a dose-dependent manner in intact arterial tissues, which was independent of extracellular Ca2+ and was not affected by receptor blockers such as atropine, methysergide and diphenhydramine. Moreover, ET1 was shown to induce an increase in 1,2-diacylglycerol. These results indicate that the activation of ET1 receptors on porcine coronary artery smooth muscle causes phosphoinositide breakdown, leading to intracellular Ca2+ mobilization and protein kinase C activation. It is suggested that phospholipase C-mediated phosphoinositide breakdown as well as previously reported activation of voltage-dependent Ca2+ channels are involved in the mechanism of ET1-induced vasoconstriction.     

The distribution of an immunoreactive endothelin-like substance in the nervous system of the nereid,Neanthes diversicolor (Annelida)

Summary The distribution of an immunoreactive endothelin-1-like peptide was investigated in the nereid, Neanthes diversicolor, using an antiserum raised against synthetic endothelin-1. Immunoreactive perikarya were localized in the brain, and nerve fibers containing endothelin-1-like material were found in the neuropil occupying the central portion of the brain. No immunostained fiber elements were traced in the circumesophageal connectives. Immunoreactive perikarya occurred in the subesophageal ganglion. From this ganglion, specifically stained fibers run posteriorly toward the ventral nerve cord. In each segmental ganglion, immunoreactive neurons were observed in medio-ventral and latero-ventral regions, and one or two marked fibers extended to the parapodium. In the parapodium, small immunoreactive perikarya and fiber elements were visible. Immunolabeled fibers occurred in the stomatogastric nerves, in the wall of the buccal cavity, and in the pharynx, esophagus, intestine and its anal region. Immunoreactive perikarya and nerve fibers were visualized between the circular muscle layer and epithelial cell layer in the esophagus and intestine. The endothelin-1-like substance shown to occur in N. diversicolor appears to function as a neurotransmitter or neuromodulator.     

Immunoreactive atrial natriuretic peptide in the fish heart and blood plasma examined by electron microscopy,immunohistochemistry and radioimmunoassay

Summary The immunoreactivity of atrial natriuretic peptide and ultrastructure of cardiocytes were examined in 5 species each of freshwater and seawater teleosts, as well as in 2 species each of elasmobranchs and cyclostomes. Immunoreactivity was strong in the atria of Cyprinus carpio, Anguilla japonica and Conger myriaster, rather weak in atria of Channa maculata, Lepomis macrochirus, Salmo gairdneri, Oplegnathus fasciatus and Eptatretus burgeri, very weak in atria of Pagrus major, Trachurus japonicus and Triakis scyllia, and not detectable in atria of Hexagrammos otakii, Narke japonica and Lampetra japonica. The immunoreactivity of the atrial cardiocytes was generally stronger in freshwater than seawater fish. Ventricular immunoreactivity was detected only in 7 species, always being weaker than that observed in the atrium. Ultrastructurally, however, secretory granules were found in atria and ventricles of all species examined, being more frequent in the former than the latter. By radioimmunoassay, immunoreactive ANP was detected in the extracts of blood plasma and both atrial and ventricular tissues of all species examined. There were no statistically significant differences in the values between freshwater and seawater species.     

Floristic study of <Emphasis Type="Italic">Geastrum</Emphasis> in Japan: three new records for Japanese mycobiota and reexamination of the authentic specimen of <Emphasis Type="Italic">Geastrum minus</Emphasis> reported by Sanshi Imai

Geastrum berkeleyi, G. fornicatum, and G. minimum are newly recorded from Japan. A peristome of G. fornicatum has hitherto been described as indistinct, whereas the Japanese specimens have a well-delimited, fibrillose peristome. Geastrum minus, reported for the first time from Japan by Sanshi Imai, represents G. quadrifidum. Macroscopic and microscopic features of those four taxa are described and illustrated based on Japanese specimens.     

<Emphasis Type="Italic">Pluteus magnus</Emphasis> and <Emphasis Type="Italic">Pluteus podospileus</Emphasis> f. <Emphasis Type="Italic">podospileus</Emphasis>, two agaric species new to Japan

Two taxa of the genus Pluteus, i.e., Pluteus magnus and Pluteus podospileus f. podospileus, are newly recorded from Japan. The macroscopic and microscopic features of these two species are described and illustrated.     

A lycoperdaceous fungus, Arachnion album (Agaricales, Arachniaceae), newly found in Japan

Arachnion album was collected in Osaka and Hyogo Prefectures, western Honshu, Japan. This is a new record of this genus for Japan. Macro- and microscopic features of the species are described and illustrated based on the Japanese specimens, and comparisons with some related taxa of A. album are given.     

The Drosophila TRPA channel, Painless, regulates sexual receptivity in virgin females

Transient receptor potential (TRP) channels play crucial roles in sensory perception. Expression of the Drosophila painless ( pain ) gene, a homolog of the mammalian TRPA1/ANKTM1 gene, in the peripheral nervous system is required for avoidance behavior of noxious heat or wasabi. In this study, we report a novel role of the Pain TRP channel expressed in the nervous system in the sexual receptivity in Drosophila virgin females. Compared with wild-type females, pain mutant females copulated with wild-type males significantly earlier. Wild-type males showed comparable courtship latency and courtship index toward wild-type and pain mutant females. Therefore, the early copulation observed in wild-type male and pain mutant female pairs is the result of enhanced sexual receptivity in pain mutant females. Involvement of pain in enhanced female sexual receptivity was confirmed by rescue experiments in which expression of a pain transgene in a pain mutant background restored the female sexual receptivity to the wild-type level. Targeted expression of pain RNA interference (RNAi) in putative cholinergic or GABAergic neurons phenocopied the mutant phenotype of pain females. However, target expression of pain RNAi in dopaminergic neurons did not affect female sexual receptivity. In addition, conditional suppression of neurotransmission in putative GABAergic neurons resulted in a similar enhanced sexual receptivity. Our results suggest that Pain TRP channels expressed in cholinergic and/or GABAergic neurons are involved in female sexual receptivity.     

miR-200b precursor can ameliorate renal tubulointerstitial fibrosis

Members of the miR-200 family of micro RNAs (miRNAs) have been shown to inhibit epithelial-mesenchymal transition (EMT). EMT of tubular epithelial cells is the mechanism by which renal fibroblasts are generated. Here we show that miR-200 family members inhibit transforming growth factor-beta (TGF-beta)-induced EMT of tubular cells. Unilateral ureter obstruction (UUO) is a common model of EMT of tubular cells and subsequent tubulointerstitial fibrosis. In order to examine the role of miR-200 family members in tubulointerstitial fibrosis, their expression was investigated in the kidneys of UUO mice. The expression of miR-200 family miRNAs was increased in a time-dependent manner, with induction of miR-200b most pronounced. To clarify the effect of miR-200b on tubulointerstitial fibrosis, we injected miR-200b precursor intravenously. A single injection of 0.5 nM miR-200b precursor was sufficient to inhibit the increase of collagen types I, III and fibronectin in obstructed kidneys, and amelioration of fibrosis was confirmed by observation of the kidneys with Azan staining. miR-200 family members have been previously shown to inhibit EMT by reducing the expression of ZEB-1 and ZEB-2 which are known repressors of E-cadherin. We demonstrated that expression of ZEB-1 and ZEB-2 was increased after ureter obstruction and that administration of the miR-200b precursor reversed this effect. In summary, these results indicate that miR-200 family is up-regulated after ureter obstruction, miR-200b being strongly induced, and that miR-200b ameliorates tubulointerstitial fibrosis in obstructed kidneys. We suggest that members of the miR-200 family, and miR-200b specifically, might constitute novel therapeutic targets in kidney disease.     

Hypothalamic GPR40 Signaling Activated by Free Long Chain Fatty Acids Suppresses CFA-Induced Inflammatory Chronic Pain

GPR40 has been reported to be activated by long-chain fatty acids, such as docosahexaenoic acid (DHA). However, reports studying functional role of GPR40 in the brain are lacking. The present study focused on the relationship between pain regulation and GPR40, investigating the functional roles of hypothalamic GPR40 during chronic pain caused using a complete Freund''s adjuvant (CFA)-induced inflammatory chronic pain mouse model. GPR40 protein expression in the hypothalamus was transiently increased at day 7, but not at days 1, 3 and 14, after CFA injection. GPR40 was co-localized with NeuN, a neuron marker, but not with glial fibrillary acidic protein (GFAP), an astrocyte marker. At day 1 after CFA injection, GFAP protein expression was markedly increased in the hypothalamus. These increases were significantly inhibited by the intracerebroventricular injection of flavopiridol (15 nmol), a cyclin-dependent kinase inhibitor, depending on the decreases in both the increment of GPR40 protein expression and the induction of mechanical allodynia and thermal hyperalgesia at day 7 after CFA injection. Furthermore, the level of DHA in the hypothalamus tissue was significantly increased in a flavopiridol reversible manner at day 1, but not at day 7, after CFA injection. The intracerebroventricular injection of DHA (50 µg) and GW9508 (1.0 µg), a GPR40-selective agonist, significantly reduced mechanical allodynia and thermal hyperalgesia at day 7, but not at day 1, after CFA injection. These effects were inhibited by intracerebroventricular pretreatment with GW1100 (10 µg), a GPR40 antagonist. The protein expression of GPR40 was colocalized with that of β-endorphin and proopiomelanocortin, and a single intracerebroventricular injection of GW9508 (1.0 µg) significantly increased the number of neurons double-stained for c-Fos and proopiomelanocortin in the arcuate nucleus of the hypothalamus. Our findings suggest that hypothalamic GPR40 activated by free long chain fatty acids might have an important role in this pain control system.