Discovery of Endocotyle incana and Spelotrema pseudogonotyla (Digenea: Microphallidae) from Scolopacid Migratory Birds in Korea

Migratory birds have been suspected as playing a central role in transmission of various trematodes, but few surveys have been undertaken in the Republic of Korea. In the present study, we describe new fauna of microphallid flukes in Korea. Two species of microphallids were found in the intestines of 2 migratory bird species, namely the red necked stints (Calidris ruficollis) and the terek sandpiper (Xenus cinereus), in a coastal area of Gunsan-si, Jeollabuk-do. The microphallids recovered from the latter were 451 microm in length and 217 microm in width, and the eggs were very small, 13 microm by 8 microm. They had the characteristic extracecal vitellaria intruding into the median posttesticular area, belonging to Endocotyle incana. Another microphallids were discovered from both migratory birds, 417 microm in length and 249 microm in width. The cirrus was projecting into the genital atrium in form of male papilla, and bounded by a muscular flap, termed pseudogonotyl. They were identified as Spelotrema pseudogonotyla in consideration of the distinctive male papilla and pseudogonotyl. Besides these flukes, Maritrema obstipum and Gynaecotyla squatarolae also were recovered. This paper is in fact the first report on the presence of Spelotrema and Endocotyle in Korea.

Influence of GABAergic Receptors on Catecholamine Secretion in the Isolated Rat Adrenal Glands

BACKGROUND: The influence of gamma-aminobutyric acid(GABA), which is well-known as a major inhibitory neurotransmitter in central nervous system, on secretion of catecholamines(CA) was investigated in the isolated perfused rat adrenal gland. METHODS: Mature male Sprague-Dawley rats were anesthetized with ether. Ther adrenal gland was isolated by the methods f Wakade. A cannula used for perfusion of the adrenal gladn was inserted into the distal end of the renal vein. The adrenal gland, along with ligated blood vessels and the cannula, was carefully removed from the animal and placed on a platform of a leucite chamber. RESULTS: GABA given into an adrenal vein of the rat produced markedly secretion of CA from the adrenal gland. Tachyphylaxis to the relesing effect of CA evoked by GABA was observed. The secretory effect of CA evoked by GABA was attenuated singnificantly by pretreatment with mecamylamine or atropine. Ouabain inhibited greatly the secretory response of GABA. When omitting the external potassium ion, the basal release of CA was increased. During this period GABA no longer revealed the increase in CA release. CA secretion evoked by GABA was blocked significantly by perfusion of calcium-free Krebs solution containing 5mMEGTA for 30-min. Pretreatment with bicuculline or picrotoxin inhibited CA secretion evoked by GABA as well as ACh. ACh-evoked CA release was potentiated by GABA infusion(400ug/30min). CONCLUSION: The experimental findings suggest that GABA causes the secretory effect of CA in a fashion of external calcium and potassium iosn-dependence, and that this releasing effect of CA induced by GABA may be exterted by stimulation of GABAergic A-reccptors located on adrenomedullary chromaffine cell, which is likely associated with cholinergic receptor activation evoked CA secretion.

A Study on the Role of Catecholamine in Reperfusion Damage of Ischemic Heart in Rat : Effect on Xanthine Oxidase Conversion

The present study was performed to investigate the role catecholamine in the genesis of reperfusion injury of ischemic heart. The possible involvement of catecholamine in the xanthine oxidase-linked production of oxygen free radicals was studied. langendorff preparations of rat hearts were made ischemic for 60 min followed by reperfusion. Upon reperfusion norepinephrine(NE) was significantly released into the coronary effluent regardless of oxygenation of the perfusion solution. Both the increased releases of creatine phosphokinase(CPK) and malondialdehyde(MDA) and the production of superoxide anion in the ischemic-reperfused hearts were significantly reduced by the treatment with either reserpine, a catecholamine depletor, or propranolol, a beta-adrenergic receptor blocker. In the reserpinized hearts, infusion of exogenous NE reversed the releases of CPK and MDA and the superoxide anion production to the original higher levels. The releases of CPK and MDA as well as the production of superoxide anion induced by NE in the reserpinized hearts were significantly depressed either by allopurinol, a specific competitive inhibior of xanthine oxidase(XOD), or by the calcium removal from the perfusion solution. Compared with the XOD activity of control ischemic hearts, that of the hearts treated with reserpine or propranolol showed lower activity in the oxygen radical producing 0-form and higher activity in D/0-form. In the reserpinized ischemic hearts, infusion of exogenous NE increased 0-form, but decreased D/0-form of XOD. The changes in XOD activities induced by exogenous NE was prevented by phenylmethylsulfonyl fluoride(a serine protease inhibitor) and pimoxide(a calmodulin inhibitor) as well as by calcium removal from the perfusion solution. It is suggested from the results that in the inchemic-reperfused heart of rat catecholamine participates in D/0 to 0-form conversion of XOD by promoting the calcium-calmodulin-dependent proteolysis and plays a contributing role in the production of oxygen free radical.