bluuebunny/crossref_metadata_2025_split huggingface dataset:
AUGMENTED Ca2+ MOBILIZATION IS A HYPERTENSIVE TRAIT DISCRIMINATED FROM A ‘MAJOR GENE’ IN BACKCROSS ANALYSIS BETWEEN SHR AND DONRYU RATS
Authors: Ohno Yoichi , Suzuki Hiromichi , Matsuo Koichi , Tanase Hisao , Takano Toshiya , Saruta Takao 
Published: June 2007

Summary1. Blood pressure and Ca2+ mobilization were significantly greater in SHR than in Donryu and F1 rats.2. Backcross linkage analysis between spontaneously hypertensive rats and normotensive Donryu rats was performed to dissect polygenic hypertensive traits and to detect the existence of a single ‘major gene’.3. Cluster and discriminant analysis of a scattergram of blood pressure versus Ca2+ mobilization classified the back‐crossed rats into two groups. The two groups were referred to the higher group and the lower group with regard to their relative blood pressure values.4. Blood pressure was correlated with Ca2+ mobilization in each group; the correlation coefficients were 0.41 for the higher group (P < 0.01) and 0.71 for the lower group (P < 0.0001).
DIFFERENCES IN THE CHARACTERIZATION OF THE Ca2+ CURRENT IN VENTRICULAR MYOCYTES BETWEEN SPONTANEOUSLY HYPERTENSIVE RATS AND NORMOTENSIVE RATS
Authors: Nakata Tomoe , Sato Sadayuki , Hachisu Mitsugu , Tsutsumi Takeshi , Osada Hirofumi 
Published: June 2007

Summary1. The slow inward Ca2+ current elicited at the membrane potential ‐ 30 mV in SHR and normotensive Wistar rats (WR) with voltage‐clamp recording was examined for this study.2. The maximal Ca2+ current of WR in the current‐voltage relationship showed the unified membrane potential of + 10 mV and the amplitude was −1.2 ± 0.2PA. In the case of SHR, however, the maximal Ca2+ current showed a lower and variable membrane potential between 0 and −20 mV. The amplitudes were −1.7 ± 0.9 pA at 0mV, −2.1 ± 0.8 pA at −10mV and −4.4 ± 0.3 pA at −20mV.3. From the cell‐attached patch‐clamp recording, the conductance of unitary Ca2+ current and the slope value were the same in SHR and in WR. From the open‐time histogram of the Ca2+ channel, the open state probability in SHR increased and the time constant from the exponential curve became slightly extended in SHR.4. L‐isoproterenol at 10‐6mol/L increased the Ca2+ current in SHR and WR. The increased ratio of Ca2+ current by I‐isoproterenol was smaller in SHR than that in WR.5. The aspect of 1–4 suggests that the increase in Ca2+ current in SHR obtained by the voltage‐clamp was explained partly by the increase of open‐state probability of unitary Ca2+ channel activity, and that a possibility of Ca+2 channel being activated by phosphorylation through cAMP did not eventuate.
SPIN‐LABELLING STUDY OF BIOMEMBRANES IN SPONTANEOUSLY HYPERTENSIVE RATS: CALCIUM‐ AND CALMODULIN‐DEPENDENT REGULATION
Authors: Tsuda Kazushi , Minatogawa Yohsuke , Iwahashi Hideo , Nishio Ichiro , Kido Ryo , Masuyama Yoshiaki 
Published: June 2007

Summary1. The present study was performed to investigate alterations in membrane characteristics of spontaneously hypertensive rats (SHR) by using an electron paramagnetic resonance (EPR) and spin‐labelling methods.2. Washed erythrocytes from SHR were examined and compared with erythrocytes from age‐matched normotensive Wistar‐Kyoto (WKY) rats.3. The values of outer hyperfine splitting (2T'll) and that of the order parameter (S) obtained from EPR spectra for a spin label agent (5‐nitroxide stearate) were significantly higher in the erythrocytes of SHR than in those of WKY rats.4. When calcium (Ca2+) was loaded to erythrocytes with a Ca2+ ionophore (A 23187), the order parameter (S) of the EPR spectra showed a greater increase in SHR than in WKY rats. Furthermore, the Ca2+‐induced change in the order parameter (S) of SHR was significantly antagonized by pretreatment of the Ca2+ antagonists (verapamil, diltiazem) and a calmodulin antagonist (W‐7).5. The results show that the erythrocyte membranes of SHR tolerated different spin motions from those of normotensive WKY rats in the EPR study, which might be associated with the idea that the membrane fluidity might be lower in SHR. Furthermore, the data suggest that Ca2+‐calmodulin antagonists may ameliorate the Ca2+‐induced changes in membrane functions in hypertension.
REGULATION OF VASCULAR CONTRACTION BY IONIC MATRIX SURFACES OF THE SMOOTH MUSCLE CELL: CHANGES IN SHR?
Authors: Kravtsov G. M. , Kwan C. Y. 
Published: June 2007

Summary1. KCl‐induced contractions in aortic rings of spontaneously hypertensive rats (SHR) and two normotensive strains, Sprague‐Dawley (SD) and Wistar‐Kyoto (WKY) rats, were studied.2. The contraction elicited by isotonic Na‐free, KCl solution containing 2.5mmol/L Ca and 1 mmol/L Mg was concentration‐dependently inhibited by Na and K. Maximal inhibition was induced by 20 mmol/L NaCl in WKY and SHR (65 and 85%, respectively) and by 60 rnmol/L NaCl in SD (50%). KCl (10–40 mmol/L) had no effect on SD but produced almost full relaxation in WKY and about 50% relaxation in SHR.3. Isotonic Ca‐free, Na‐free high Mg (2 mmol/L), K‐solution caused strong phasic contractions in WKY and SHR, but weak responses in SD.4. Aortic rings of SD, WKY and SHR developed strong, sustained and reproducible contractions in isotonic Ca‐free, Na‐free, K‐solution containing EDTA, which were fully relaxed by 1.2, 1.6 and 8 mmol/L Na, respectively.5. We suggest that the primary mechanism of KCl‐contraction is potential‐independent competition between monovalent and divalent cations for binding sites on both surfaces of the plasma membrane (e.g. K with Mg and Na with Ca) and that differences in aortic contractility in SHR, WKY and SD merely reflect strain differences in the composition of the ionic matrix, independent of hypertension.
INTESTINAL CALCIUM ABSORPTION AND RESPONSE OF CALCIUM REGULATING HORMONES IN THE STROKE‐PRONE SPONTANEOUSLY HYPERTENSIVE RAT AS A MODEL OF OSTEOPOROSIS
Authors: Fukuda Satoshi , Tsuchikura Satoru , Iida Haruzo , Ikeda Katsumi , Nara Yasuo , Yamori Yukio 
Published: June 2007

Summary1. Because of low levels of serum calcium (Ca) in stroke‐prone spontaneously hypertensive rats (SHRSP), intestinal Ca absorption and urinary Ca excretion were examined.2. SHRSP were observed to have lower intestinal Ca absorption and higher urinary Ca excretion, but with a latent function of intestinal Ca absorption able to respond with calcium regulating hormones to Ca loading in the aged, especially to a new Ca agent as examined in this study.
COMPARISON OF THE EFFECTS OF HYPERCHOLESTEROLAEMIA ON RELAXATION RESPONSES IN AORTAS OF SPONTANEOUSLY HYPERTENSIVE RATS AND DAHL SALT‐SENSITIVE RATS
Authors: Kitagawa S. , Sameshima E. , Yamaguchi Y. , Kwon Y. , Shinozuka K. , Kunitomo M. 
Published: June 2007

Summary1. We investigated the effects of hypercholesterolaemia on relaxation responses in thoracic aortas isolated from two different types of hypertensive rats; spontaneously hypertensive rats (SHR) and Dahl salt‐sensitive rats (DSR).2. All rats fed the high cholesterol diet for 8 weeks showed a significant increase in the serum cholesterol level. The high‐cholesterol diet did not change the blood pressure of SHR, but increased that of hypertensive DSR fed a high‐salt diet.3. In aortas of SHR, the high‐cholesterol diet did not change the endothelium‐dependent and ‐independent relaxation induced by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively.4. In aortas of hypertensive DSR, the high‐cholesterol diet notably reduced the ACh‐induced relaxations and slightly reduced SNP‐induced relaxation.5. These results suggest that hypercholesterolaemia causes greater impairment of endothelium‐dependent relaxation in rat aorta with salt‐induced hypertension than genetic hypertension.
INCREASED IMMUNOREACTIVITIES FOR THE BASIC FIBROBLAST GROWTH FACTOR AND ITS RECEPTOR IN ASTROCYTES AT THE SITE OF CEREBRAL LESIONS AND OEDEMATOUS CHANGE IN SHR
Authors: Kataoka Hideo , Yamada Eiji , Hayase Yoneko , Hazama Fumitada 
Published: June 2007

Summary1. To obtain information about changes of basic fibroblast growth factor (bFGF) in the brain in chronic hypertension, we immunohistochemically studied the distribution and level of bFGF and its receptor in the brain of stroke‐prone spontaneously hypertensive rats (SHRSP).2. In the control normotensive rats, immunoreactivity for bFGF was demonstrated in nerve cells, while there was almost no reactivity in astrocytes.3. In SHRSP, there was a marked immunoreactivity in the densely accumulated reactive cells, particularly astrocytes, in and around cerebral cortical lesions. Slightly increased reaction for bFGF was found in the nerve cells around lesions. Astrocytes in the subcortical white matter on both ipsi‐ and contra‐lateral sides of the cortical lesion also showed immunoreactivity for bFGF. The location of increased bFGF expression in SHRSP corresponded very well with the site of extravasated plasma fluid demonstrated by anti‐fibrinogen antibody. Electron microscopically, bFGF was shown in astrocytes along the rough endoplasmic reticulum suggesting the growth factor to be produced in the cells and not to be taken up from the surroundings. Expression of FGF‐receptor was also demonstrated in reactive astrocytes in the oedematous cortical portion around lesion and in the oedematous subcortical white matter.4. These findings indicate the possibility that oedema and the simultaneously generated free radicals or some extravasated plasma components express bFGF in astrocytes and probably in nerve cells as well as FGF‐receptor in astrocytes, and that the thus expressed bFGF and its receptor play some role in the sequence of developmental events of hypertensive cerebral lesions.
MITOCHONDRIAL ABNORMALITIES IN HYPERTROPHIED MYOCARDIUM OF STROKE‐PRONE SPONTANEOUSLY HYPERTENSIVE RATS
Authors: Tokoro T. , Ito H. , Maenishi O. , Suzuki T. 
Published: June 2007

Summary1. To clarify the pathogenesis of cardiac disorders in SHRSP which showed severe cardiac hypertrophy and myocardial degeneration in the hypertensive stage, restriction fragment length polymorphisms (RFLP) of mitochondrial DNA (mtDNA), and morphological and functional changes of mitochondria were examined.2. Morphologically, the mitochondrial size showed a wider range of distribution in SHRSP both at prehypertensive and hypertensive stage compared to those in age‐matched WKY.3. Isocitrate dehydrogenase (ICDH) activity, but not super‐oxide dismutase (SOD) activity, was higher in the young SHRSP, whereas both enzyme activities were lower in the mature SHRSP than in the age‐matched WKY.4. RFLP analysis by electrophoresis revealed that the loss of two restriction sites for Rsa I in the myocardial mtDNA from the SHRSP, but not in that from the WKY.5. These findings suggest that the structural changes of mtDNA could be related, at least partly, to morphological and functional changes of mitochondria in the SHRSP myocardium.
CHRONIC EXOGENOUS HYPERINSULINAEMIA ACCELERATES THE DEVELOPMENT OF HYPERTENSION IN SPONTANEOUSLY HYPERTENSIVE RATS
Authors: Bursztyn Michael , Ben‐Ishay Drori , Mekler Judith , Raz Itamar 
Published: June 2007

Summary1. An association between hyperinsulinaemia, insulin resistance and hypertension was previously described in spontaneously hypertensive rats (SHR). We therefore tested whether chronic exogenous hyperinsulinaemia, which did not affect blood pressure of normotensive rats, may aggravate hypertension in young SHR.2. Insulin was administered for 4 weeks by a graded increase of a sustained release insulin implant, without carbohydrate supplementation.3. Initial bodyweight of seven SHR and five sham‐implanted control SHR, aged 6–8 weeks, was not different between the groups or by week 4.4. Glucose levels decreased in the treated rats [2‐way anova F (1:10) = 18.7. P < 0.005] and were 7.3 ± 0.1 mmol/L in the controls and 4.4 ± 0.7 mmol/L in the treated SHR, respectively. Insulin levels were comparable at baseline and increased to 1002 ± 978 pmol/L in treated rats at week 4 while remaining 270 ± 78pmol/L in the controls [F (1:10) = 6.1, P < 0.05]. The systolic blood pressure (tail‐cuff) was significantly increased in insulin treated SHR in weeks 1–3 [F (1: 10) = 5.1, P < 0.05] though it was comparable at baseline and week 4.5. In the presence of a hypertensive predisposition, chronic exogenous hyperinsulinaemia accelerates the time course of the development of hypertension without affecting its severity.
ALTERED UTERINE ENVIRONMENT IN THE SPONTANEOUSLY HYPERTENSIVE RAT
Authors: Erkadius E. , Morgan T. O. , Di Nicolantonio R. 
Published: June 2007

Summary1. In order to determine the role of the uterine environment in the development of hypertension in the spontaneously hypertensive rat (SHR) we examined the patterns of fetal and placental growth and the composition of amniotic fluid of SHR and normotensive Wistar‐Kyoto (WKY) rats during the final trimester of pregnancy.2. SHR and WKY embryos and amniotic fluid were collected at days 15 and 20 of pregnancy, and fetal and placental weight and amniotic fluid volume were recorded. The sodium and potassium concentration of amniotic fluid was also measured.3. Fetal and placental weights were significantly lower in SHR compared to WKY at 15 and 20 days of gestation. Amniotic fluid volume was significantly lower in SHR at 15 days, but significantly higher at 20 days. Amniotic fluid sodium concentration was significantly lower in SHR at 15 days but not different at 20 days when compared to WKY. Potassium concentration was lower in SHR at both ages.4. Thus the reduced placental weight early in the gestational period of the SHR may play a role in its underdevelopment in utero and hence its reduced birthweight. The SHR foetus is also bathed in a hypokalaemic amniotic fluid of increased volume. How this might influence fetal development and later blood pressure is unclear. Also whether these changes are of maternal or fetal origin remain to be determined.
PLACENTAL NA+, K+ ACTIVATED ATP‐ASE ACTIVITY IN SHRSP IN CONNECTION WITH PREGNANCY INDUCED HYPERTENSION AND INTRA‐UTERINE GROWTH RETARDATION
Authors: Fuchi Isao , Higashino Hideaki , Noda Kiichiro , Suzuki Aritomo , Matsubara Yoshiharu 
Published: June 2007

Summary1. Placental Na+, K+‐ATPase activities were measured in connection with the active transport of amino acid, intrauterine growth retardation (IUGR) or small for date infants (SFD) in salt‐loaded pregnant SHRSP.2. All parameters such as fetal weight, placental weight and Na+, K+‐ATPase activity in the placental tissue were significantly depressed in SHRSP, especially in the salt‐loaded SHRSP compared with WKY.3. Besides a decrease of blood flow, a decline of Na+, K+‐ATPase activity associated with an active transport of amino acid in the placenta would cause IUGR and SFD in the salt‐loaded pregnant SHRSP.4. Pregnant SHRSP given water containing salt would be a good model for pregnancy induced hypertension in humans.
STUDIES ON PREGNANCY HYPERTENSION AND IUGR‐SFD EFFECTS OF DRUGS ON THE BLOOD VESSELS IN THE PLACENTA OF PREGNANT SHRSP
Authors: Fuchi Isao , Noda Kiichiro , Matsubara Yoshiharu 
Published: June 2007

Summary1. Based upon our previous work, we came to the conclusion that a decrease in placental blood volume was a possible factor behind intrauterine growth retardation (IUGR) in pregnancy‐induced hypertension.2. In a second study, we used an image analysis system to measure cross‐sectional areas and wall thicknesses of central blood vessels of the spiral artery, the so‐called ‘central artery’.3. It was thought that one of the more basic factors behind IUGR in pregnancy‐induced hypertension might possibly be narrowings and spasms of the maternal placental blood vessels.4. In this study, we found that the three drugs we used (MgSO4.7H2O, Solcoseryl and KCl) all resulted in an enlargement of the cross‐sectional areas of the maternal blood vessels, and that MgSO4.7H2O, in particular, also relaxed maternal blood vessel spasms in SHRSP placenta.
ELECTROMYOGRAPHY DATA ON SPONTANEOUSLY HYPERTENSIVE RATS
Authors: Jacupow Eduard Z. , Khasanova Dina R. , Oslopow Vladimir N. , Khasanow Niyaz R. , Ismagilow Maxum F. 
Published: June 2007

Summary1. To investigate the state of nerve‐muscle excitability in 20 spontaneously hypertensive rats and 22 Wistar rats local electromyography was carried out in periods of rest and under the maximum strain of 10 min ischaemia of m.flexor femoris (Trusso's test).2. The electromyography phenomenon found in the SHR group corresponds to typical tetany electromyography correlatives.3. Thus, changes occur to the nerve‐muscle excitability state according to the neurogenic tetany type.
PROPER MEASUREMENT OF BLOOD PRESSURE AND HEART RATE IN SHRSP AND WKY BY AN INDIRECT VOLUME‐OSCILLOMETRIC METHOD
Authors: Higashino H. , Sirneonova K. , Lambev I. , Markov M. , Suzuki A. 
Published: June 2007

Summary1. The effect of environmental temperature on the indirect measurement of rat blood pressure and heart rate was investigated with special reference to the tail arterial blood flow in both strains of SHRSP and WKY.2. Very good correlations (r > 0.82, P < 0.05; t‐test, 10 d.f.) were observed between the two values of systolic blood pressure or heart rate measured by a direct and an indirect method at environmental temperatures between 26 and 38°C in SHRSP, and 34 and 38°C in WKY, respectively.3. When the temperature was elevated by 10°C from 25°C to 35°C, the regional blood flow in the tail artery increased by 52–69%, sufficient to detect a blood flow increase by the indirect method.4. These data showed that the best way to measure the accurate blood pressure and heart rate in both strains of SHRSP and WKY by the indirect volume‐oscillometric method was to hold the rats at 34–36°C for 5 min.
EFFECTS OF NUTRITIONAL FACTORS ON REPRODUCTION, GROWTH, PREWEANING REFLEX DEVELOPMENT AND POSTWEANING LEARNING PERFORMANCE IN SHRSP
Authors: Matsuo T. , Kihara T. , Tanimura T. 
Published: June 2007

Summary1. Dietary high protein intake in stroke‐prone spontaneously hypertensive rats (SHRSP) induces a reduction of blood pressure and decreases the incidence of cerebral lesion. The objective of this investigation was to determine the effects of nutritional factors of dietary high protein on reproduction, growth, pre‐weaning reflex development, postweaning behaviour and learning performance in SHRSP.2. SHRSP were fed on a high protein rat diet (OA2 diet) and a standard rat diet for SHRSP (FSP diet). Rats were mated by brother‐sister combinations and observed on reproductive performance, preweaning reflex development and postweaning learning performance among the 3rd to the 6th generations.3. OA2 showed some advanced responses at the preweaning period compared to FSP in the surface righting, negative geotaxis and mid‐air righting reflexes.4. At the postweaning period, hyperactivity of OA2 was indicated at the open field test. In the ambulatory activity of the circadian rhythm, OA2 was better synchronized with running activity in the light and dark alternation cycle.5. OA2 group indicated the higher postweaning learning performance in the water E, the water multiple T (Biel) and the Morris water‐maze test as well as the acquisition of the conditioned avoidance response test.6. In conclusion, dietary high protein intake in SHRSP produced some advanced effects on preweaning reflex development and postweaning learning performance.
SESAME LIGNANS MODULATE CHOLESTEROL METABOLISM IN THE STROKE‐PRONE SPONTANEOUSLY HYPERTENSIVE RAT
Authors: Ogawa Hiroshi , Sasagawa Sukenari , Murakami Tetsuo , Yoshizumi Hazime 
Published: June 2007

Summary1. Effects of sesamin and episesamin (an epimer of sesamin) on lipid metabolism, in particular cholesterol metabolism, were examined in normocholesterolaemic and hypercholestero‐laemic stroke‐prone spontaneously hypertensive rats (SHRSP).2. In normocholesterolaemic SHRSP fed a regular diet, both sesamin and episesamin significantly increased the concentration of serum total cholesterol, which was due to an increase of high density lipoprotein (HDL) subfraction rich in apoE (apoE‐HDL). In addition, both substances effectively decreased serum very low density lipoprotein (VLDL). In the liver, only episesamin significantly decreased the activity of microsomal acyl‐CoA: cholesterol acyltransferase.3. In hypercholesterolaemic SHRSP fed a high‐fat and high‐cholesterol diet (HFC diet), only episesamin improved serum lipoprotein metabolism with an increase in apoA‐I and a decrease in apoB. In the liver, both sesamin and episesamin significantly suppressed cholesterol accumulation. Interestingly, only episesamin significantly increased the activity of microsomal cholesterol 7α‐hydroxylase.4. These results indicate that sesamin may be effective in preventing cholesterol accumulation in the liver. In comparison with sesamin, episesamin may be effective in the regulation of cholesterol metabolism in the serum and liver.
EFFECT OF LOVASTATIN AND FLUOROMEVALONATE ON PHOSPHATIDYLINOSITOL 3‐KINASE ACTIVITY STIMULATED WITH PDGF
Authors: Iwama A. , Sawamura M. , Nara Y. , Yamori Y. 
Published: June 2007

Summary1. Phosphatidylinositol 3‐kinase (PI3K) appears to have a crucial role in cellular proliferation induced by platelet‐derived growth factor (PDGF). However, the mode of activation of the enzyme has been unclear so far. In the present study, we investigated the effects of a cholesterol lowering drug on [3H]‐thymidine ([3H]‐TdR) incorporation and PI3K activity in cultured vascular smooth muscle cells (VSMC) stimulated with PDGF.2. PDGF stimulated both [3H]‐TdR incorporation and PI3K activity immunoprecipitated with antiphosphotyrosine antibody in a dose dependent manner (EDSO was 4 ng/mL for [3H]‐TdR uptake and 3 ng/mL for PI3K activity). Lovastatin inhibited serum‐stimulated [3H]‐TdR incorporation dose dependently. PI3K activity induced by PDGF was also inhibited in a dose dependent manner; however, its activity was 61% at 10‐6 mol/L, 72% at 10‐5 mol/L and 8% at 10‐4 mol/L of the control value.3. These inhibitory effects of lovastatin were completely abolished by adding 1 mmol/L mevalonic acid (MVA), suggesting that MVA metabolites had some important role on the PI3K activation and cellular proliferation.4. Fluoromevalonate (Fmev), a competitive inhibitor of mevalonate diphosphate (MVA‐PP) decarboxylase, inhibited [3H]‐TdR incorporation at concentrations more than 10‐6 mol/L. Moreover, marked inhibitory effect was observed at concentrations of 10‐7 and 10‐8 mol/L (76% of control). PI3K activity was also reduced by 10‐3 mol/L Fmev (0.2% of control). However, in contrast to [3H]‐TdR uptake, there was no inhibitory effect detected at concentrations up to 10‐4 mol/L.5. These results suggest that PDGF‐stimulated PI3K activity as well as cellular proliferation was modified by protein isoprenylation.
LONG‐TERM THERAPEUTIC EFFECTS OF ACE INHIBITOR AND CALCIUM ANTAGONISTS ON HYPERTENSIVE VASCULAR LESIONS IN M‐SHRSP
Authors: Ohta Yoshio , Chikugo Taka‐aki , Suzuki Tsuneyuki 
Published: June 2007

Summary1. Our results indicate that the drugs used in this study are very effective in malignant hypertension therapy.2. For M‐SHRSP treated with highly effective antihypertensive drugs, if blood pressure remains under 200 mmHg over the long‐term, the structures of the small arteries and/or arterioles stay as well preserved as they do in WKY.3. For M‐SHRSP treated with drugs with a lower antihyper‐tensive effect, the occurrence of cerebrovascular lesions and angionecrosis in the various organs are suppressed significantly, even though blood pressure remains over 250 mmHg over the long‐term. Based upon effect alone, there is no difference between ACEI and a calcium antagonist. However, inhibition of the proliferation of vascular smooth muscle cells is more potent in the former than in the latter.4. These results suggest that ACEI might have the potential to suppress smooth muscle cell proliferation independent of high blood pressure.