• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.161-166
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• 1990

Infusion of bradykinin (BK) into the renal arteries increases sodium excretion. However, it is not clear whether natriuresis results from the renal hemodynamic effects or from the direct effect on renal tubular sodium transport. Therefore, we examined the effects of BK on the transport-dependent oxygen consumption in the distal tubule (DT) and cortical collecting tubule (CCT) of deoxycorticosterone-treated rats. BK inhibited oxygen consumption in a dose-dependent way with a maximal reduction at $0.1\;{\mu}M$ BK. The inhibitory effect of BK was not present in the absence of sodium or in the presence of ouabain (1 mM). These data imply that the inhibitory effect of BK is restricted to the sodium transport-dependent oxygen consumption. We also investigated the relationship between the effect of BK on oxygen consumption and arachidonic acid metabolism. Mepacrine $(10\;{\mu}M)$, an inhibitor of membrane phospholipases, prevented the inhibitory effect of BK, but indomethacin (0.5 mM) didn't. These results suggest that BK decreases the sodium transport-related oxygen consumption in the rat DT and/or CCT, and that it may be mediated by products of enzymes other than cyclooxygenase.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.5
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• pp.565-572
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• 1997

In the freshly isolated rat nephron, the effect of endothelin-1, -2 and -3 (ET-1, -2 and -3) on cytosolic free calcium concentration ($[Ca^{2+}]_i$) was determined using the fluorescent indicator Fura-2/AM. $[Ca^{2+}]_i$ increase was investigated in 9 parts of the single nephron including glomerulus (Glm), $S_1,\;S_2,\;S_3$, cortical and medullary thick ascending limb and cortical (CCT) and outer medullary collecting tubule (OMCT). Endothelins increased $[Ca^{2+}]_i$ in Glm (ET-1; $127{\pm}17%$, ET-2; $93{\pm}5%$, ET-3; $169{\pm}17%$), CCT (ET-1; $30{\pm}6%$, ET-2; $38{\pm}19%$, ET-3; $158{\pm}18%$) and OMCT (ET-1; $197{\pm}11%$, ET-2; $195{\pm}11%$, ET-3; $215{\pm}37%$) at 10-7 M. In OMCT, ET-1 and ET-2 increased $[Ca^{2+}]_i$ in a dose-dependent manner ($10^{-10}{\sim}10^{-6}$ M). To the contrary, ET-3-induced $[Ca^{2+}]_i$ rise was begun from $10^{-12}$ M. BQ-123Na, an antagonist of ETA receptor, at $10^{-4}$ M inhibited about 30% of $[Ca^{2+}]_i$ rise induced by ET-1 and -3. Binding experiments using $[^{125}I]ET-3$ showed the existence of $ET_B$ receptor in OMCT. This binding was replaced by ET-1, ET-2 or ET-3 by the almost same degree but not by angiotensin II or vasopressin.

• Applied Microscopy
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• v.38 no.2
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• pp.141-148
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• 2008

Nitric oxide (NO) is an important regulator of renal blood flow, glomerular hemodynamics, and tubule transport processes in the kidney. There is also evidence that NO is involved in cell cycle regulation and mitotic division. During development the nNOS expression pattern differs from that observed in adult animals. However, little is known about temporal and spatial patterns of nNOS expression in the developing kidney. The purpose of this study was to establish the time of expression and the distribution of nNOS in the developing rat kidney. Kidneys from 14-, 16-, 17-, 18-, and 20-day-old fetuses, 1-, 4-, 7-, 14-, and 21-day-old pups, and adult animals were preserved and processed for immunohistochemistry. In the adult kidney, nNOS was detected in the parietal epithelium of Bowman s capsule, macula densa, descending thin limb and inner medullary collecting duct. nNOS immunoreactivity appeared first in the distal tubule anlage at 15 days of gestation, and in all epithelial cells of developing thick ascending limbs (TAL) as well as macula densa of 17- and 18-day-old fetuses. From 20 days of gestation to 14 days after birth, nNOS was expressed in the newly formed cortical TAL, which are located in the medullary ray, whereas in mature TAL of juxtamedullary nephrons, nNOS immunolabeling gradually decreased in intensity and became restricted to the macula densa. In inner medullary collecting ducts, nNOS immunoreactivity appeared first at 7 days after birth in the papillary tip and gradually ascended to the border between outer and inner medulla. In the descending thin limb and parietal epithelium of Bowman's capsule, weak nNOS immunoreactivity was observed at 14 days after birth and labeling gradually increased to adult levels at 21 days after birth. These results suggest that differential expression of nNOS in the developing kidney is an important physiological regulator of renal function during kidney maturation.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.171-187
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• 1998

Garlic occupies a special position among the many foods of vegetable origin because it is the sole food for Koreans during the their lives. And vitamin A has been ingested by forms of food or additives. Cadmium has been described as one of the most dangerous trace elements in the food and environment of man and livestocks. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of cadmium-induced changes in gene expression , ie. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and damage for food hygiene. He acute and chronic combine effects of cadmium (Cd, CdCl2 20mg/kg), garlic oil(Dds: diallyl disulfide 50mg/kg, 3 times a week) and vitamin A(Ra: retinol acetate 50,000 IU/kg, 3 times a week) on Wistar male rats were evaluated concerning cadmium contents, tissues enzyme activity, HSP expression histopathological and electron microscopical examinations. The results of the study are as follows ; 1. Less cadmium was absorbed through the digestive tracts, but the ratio of contents in tissue were not changed by the simultaneous adminstration of diallyl disufide or retinol acetate. 2. ALT(alanine aminotransferase) , AST(aspartate aminotransferase), glucose, BUN (blood urea nitrogen), creatinine, the key indices of the clinical changes in hepatic and renal function were significantly hanged by the cadmium treatment after 1 week in liver, after 4 weeks in kidney. 3. Histopathological changes in cadmium treated rats were appeared at 8 weeks age treatment in kidneys. Homogenous eosinophilic material was accumulated in cortical and collecting tubular lumens at 16 weeks. Degenerated or necrotized tubular cells were observed in cortex and medulla. Degenerated seminiferous tubules and homogeneous eosinophilic material was seen in interstitial tissue of rat treated with cadmium for 16 weeks. Calcium deposits were seen in degenerated seminiferous tubules and the tubules showed severe calcification of rat treated with cadmium for 16 weeks. Electron microscope changes in kidney were observed in rats treated with CdCl2 20 mg/kg. Proximal convoluted tubule cells showed selling of cytoplasm and narrow lumen. Capillary endothelial cells showed cytoplasmic vacuoles and swelling. Degenerated epithelial cells were accumulated in tubular lumen of kidney. 4. Enhanced synthesis of 70 KDa relateve molecular mass proteins were detected in 2 hours after cadmium, exposure, with maximum activity occurring at 8~48 hours. Induction of HSP 70 was evident at proximal tubules and glomeruli in kidney. Testicular cells produced enough HSP to be detected normally. From the above results, it could be concluded that HSP70 induction by the cadmium treatment was a rapid reaction to indicated the exposure of xenobiotics, and retinol acetate reduced the cadmium induced nephrotoxicity.