caa a22 4500 46907888X CHVBK 20180323132943.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00175478 doi (NATIONALLICENCE)springer-10.1007/BF00175478 The effect of high calcium intake on Ca2+ ATPase and the tissue Na:K ratio in spontaneously hypertensive rats [Elektronische Daten] [Heikki Wuorela, Pertti Arvola, Ilkka Pörsti, Elise Siltaloppi, Pekka Säynävälammi, Heikki Vapaatalo] Summary: The effects of oral calcium loading on the development of hypertension were studied in spontaneously hypertensive rats (SHR). Forty-eight male SHR were divided into four groups according to treatment: control, calcium, deoxycorticosterone (DOC) and DOC+calcium. Both calcium groups received ad libitum 1.5% CaCl2 as drinking fluid. The DOC animals were injected with a mineralocorticoid, deoxycorticosterone trimethylacetate, 25 mg/kg, s. c., once a week. Systolic blood pressure (BP) was measured once a week by the tail cuff method. During the nine-week study, the development of hypertension was enhanced in the DOC group, while in the calcium group a blood pressure-lowering effect was observed when compared to the controls. Calcium also abolished the hypertensive effect of DOC. The maximal velocity of calcium transport was higher in "insideout”-vesicles of red blood cells as compared to controls in both calcium-supplemented groups. DOC treatment resulted in elevated sodium and potassium contents in tail artery tissue, while the effect of the combination of DOC+calcium was equal to controls. On the other hand, the tissue Na:K ratio was decreased in both tail artery wall and heart in the calcium group. Calcium treatment diminished the excretion of phosphate in both groups, while the plasma phosphate concentration was lowered in the calcium group. In mesenteric arterial rings, DOC impaired nitro-prusside-induced relaxation, while the relaxation was enhanced compared to control in both the calcium and DOC+calcium groups. As a summary, it can be assumed that in the calcium group, a higher rate of calcium extrusion via Ca2+ ATPase together with a reduction in the tissue Na:K ratio, possibly reflecting a change in Na+K+ ATPase activity, partially explain the beneficial effects of high calcium intake in blood pressure. The combination DOC+calcium, in turn, seems to oppose the effects of DOC on blood pressure via higher rate of calcium extrusion and by returning the tissue sodium and potassium contents to the control level. Springer-Verlag, 1992 Blood pressure nationallicence Ca2+ATPase nationallicence Dietary calcium loading nationallicence Na:K ratio nationallicence Spontaneously hypertensive rats nationallicence Wuorela Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Arvola Pertti Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Pörsti Ilkka Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Siltaloppi Elise Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Säynävälammi Pekka Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Vapaatalo Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/1(1992-01-01), 117-122 0028-1298 345:1<117 1992 345 210 https://doi.org/10.1007/BF00175478 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00175478 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wuorela Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Arvola Pertti Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Pörsti Ilkka Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Siltaloppi Elise Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Säynävälammi Pekka Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Vapaatalo Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/1(1992-01-01), 117-122 0028-1298 345:1<117 1992 345 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer