Free cytosolic calcium in renal proximal tubules from the spontaneously hypertensive rat.

Llibre, J.; LaPointe, Michael S.; Batlle, Daniel

doi:10.1161/01.hyp.12.4.399

Cited by 13 publications

(4 citation statements)

References 35 publications

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“…4 Rats less than 5 weeks of age were chosen for study because systolic blood pressure in the SHR at this age is not yet higher than that of age-matched WKY rats. 21 Before each experiment, the systolic blood pressure was measured by the awake tail-cuff method as previously described. 21 Rats were then anesthetized by an intraperitoneal injection of phenobarbital (5 mg/100 g body wt), and the chest cavity was opened by cutting the ribs along the sternum.…”

Section: Methodsmentioning

confidence: 99%

“…21 Before each experiment, the systolic blood pressure was measured by the awake tail-cuff method as previously described. 21 Rats were then anesthetized by an intraperitoneal injection of phenobarbital (5 mg/100 g body wt), and the chest cavity was opened by cutting the ribs along the sternum. The thymus was removed with fine forceps and cleared of blood vessels.…”

Section: Methodsmentioning

confidence: 99%

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Reduced intracellular pH in lymphocytes from the spontaneously hypertensive rat.

1990

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This study was designed to determine the cytoplasmic pH (pH,) profile of lymphocytes from a rat model of genetic hypertension that is well suited for study before and after the development of spontaneous hypertension. For this purpose, pHj was measured in thymic lymphocytes obtained from spontaneously hypertensive rats (SHR) and from age-matched Wistar-Kyoto (WKY) control rats using 2',7'-bis carboxyethyl-5,6-carboxyfluorescein (BCECF), a pHsensitive fluorescence probe. At the age of 16-20 weeks, pH, of lymphocytes suspended in a HCOj-free HEPES-buffered solution, was markedly lower in the SHR than in the WKY rats (7.07±0.02,7i=16 and 7.22±0.01, n=15, respectively,p<0.001), whereas systolic blood pressure was higher in SHR than in WKY rats (175±5.0 and 105±3.0 mm Hg, respectively,p<0.001). In rats less than 5 weeks of age, pH, was also lower in SHR than in WKY rat lymphocytes (7.12±0.04, n = l l and 7.23±0.04, n = l l , respectively, p<0.05), although at this age systolic blood pressure was not different between the two groups (87±4.0 and 85±3.0 mm Hg, respectively). In lymphocytes suspended in a more physiological HCO 3 /CO 2 -buffered solution, pHj was again lower in the adult SHR than in the WKY rat (7.18±0.02, n=U and 7.31 ±0.02, n=16, respectively,p<0.001). Under this condition, blockade of Na + -H + exchange by a specific inhibitor, ethyl-isopropyl-amiloride (EIPA), or by exposure to Na + -free media resulted in intracellular acidification in both SHR and WKY rat lymphocytes. The difference in pH ; between SHR and WKY rat lymphocytes persisted after blockade of the Na + -H + exchanger by either EIPA (7.09 ±0.04 vs. 7.20+0.03, p< 0.05) or by removal of external Na + (7.04 ±0.05 vs. 7.19±0.02,/;<0.005). Our data show that reduced pH, is a feature of lymphocytes from the SHR that is apparent before and after the development of hypertension. Persistence of reduced pHj in SHR cells, as compared with WKY rat cells, after Na + -H + blockade suggests that a primary abnormality in the activity of the Na + -H + exchanger is unlikely to account for the observed reduction in steady-state pH : of SHR cells. This alteration in pHj regulation persisted after removal of external Na + and was seen in the presence and in the absence of external HCO 3 , indicating that a sodium-independent, bicarbonate-independent mechanism of cytoplasmic acid accumulation accounts for the observed difference in pH,. (Hypertension 1990;15:97-103)

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Reduced intracellular pH in lymphocytes from the spontaneously hypertensive rat.

1990

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“…Of particular importance is that younger rats, in general, exist in a healthier metabolic state. For example, 4-wk-old Wistar control rats exhibit lower blood pressures relative to their 20-wk-old counterparts (31) and glucose tolerance has been shown to be lower in 28-wk-old vs. 8-wk-old rats (19). As espoused in an AHA Scientific Statement (5), a new sense of urgency for primordial and primary prevention strategies has led to investigations for biomarkers and mechanisms that precede the development of the metabolic syndrome and occur during childhood.…”

Section: Discussionmentioning

confidence: 99%

Early depression of Ankrd2 and Csrp3 mRNAs in the polyribosomal and whole tissue fractions in skeletal muscle with decreased voluntary running

Roberts

Childs

Brown

et al. 2012

Journal of Applied Physiology

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The wheel-lock (WL) model for depressed ambulatory activity in rats has shown metabolic maladies ensuing within 53-173 h after WL begins. We sought to determine if WL beginning after 21-23 days of voluntary running in growing female Wistar rats affected the mRNA profile in the polyribosomal fraction from plantaris muscle shortly following WL. In experiment 1, WL occurred at 0200 and muscles were harvested at 0700 daily at 5 h (WL5h, n = 4), 29 h (WL29h, n = 4), or 53 h (WL53h, n = 4) after WL. Affymetrix Rat Gene 1.0 ST Arrays were used to test the initial question as to whether WL affects mRNA occupancy on skeletal muscle polyribosomes. Using a false discovery rate of 15%, no changes in mRNAs in the polyribosomal fraction were observed at WL29h and eight mRNAs (of over 8,200 identified targets) were altered at WL53h compared with WL5h. Interestingly, two of the six downregulated genes included ankyrin repeat domain 2 (Ankrd2) and cysteine-rich protein 3/muscle LIM protein (Csrp3), both of which encode mechanical stretch sensors and RT-PCR verified their WL-induced decline. In experiment 2, whole muscle mRNA and protein levels were analyzed for Ankrd2 and Csrp3 from the muscles of WL5h (4 original samples + 2 new), WL29h (4 original), WL53h (4 original + 2 new), as well as WL173 h (n = 6 new) and animals that never ran (SED, 4-5 new). Relative to WL5h controls, whole tissue Ankrd2 and Csrp3 mRNAs were lower (P < 0.05) at WL53h, WL173h, and SED; Ankrd2 protein tended to decrease at WL53h (P = 0.054) and Csrp3 protein was less in WL173h and SED rats (P < 0.05). In summary, unique early declines in Ankrd2 and Csrp3 mRNAs were identified with removal of voluntary running, which was subsequently followed by declines in Csrp3 protein levels during longer periods of wheel lock.

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“…Differences in blood pressure can usually be discerned between SHR and WKY rats after 5 weeks of age, with frank hypertension developing after 10 or 12 weeks of age. 36 In this study we used young animals with early hypertension. In older animals involution of the thymus gland starts occurring, limiting the number of cells that can be harvested.…”

Section: Preparation Of Lymphocytesmentioning

confidence: 99%

Regulation of intracellular pH in the spontaneously hypertensive rat. Role of bicarbonate-dependent transporters.

Redón

Batlle

1994

Hypertension

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Previous studies that have evaluated the Na + -H + antiporter in cells from hypertensive subjects were generally performed under conditions in which HCO 3 -CO 2 , the physiological buffer system, was absent from the assay media. The objective of this study was to evaluate the activity of the Na + -H + antiporter and that of the Na + -dependent and Na + -independent Cr-HCO 3 " exchangers in cells assayed in the presence of HCO3-CO2 in the media. Lymphocytes from 6-to 8-week-old spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) rats were obtained from the thymus gland and assayed immediately after isolation. The activity of the Na + -H + antiporter after stimulation by cell acidification (pH, approximately 6.4) was similar in SHR and WKY rats (18.67+1.03 and 16.12±0.92 mmol H + /L per minute, respectively). Recovery from cell alkalinization was effected by an Na + -independent C1~-HCO 3~ exchanger, with maximal activity at an alkaline pH, (approximately 7.7). The stimulated activity of this Na + -independent Cr-HCO 3 " exchanger was also not different between SHR and WKY cells (2.65±0.25 and 2.55±0.32 mmol H + /Lper minute, respectively). Acute chloride removal produced a rise in pH, that was Na + -dependent and sensitive to 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) but resistant to ethylisopropylamiloride (EIPA), reflecting the activity of an Na + -dependent C1~-HCO 3~ ex-O ver the last several years the investigation of intracellular proton concentration and the Na + -H + antiporter in experimental 16 and clinical 7 " 14 hypertension has received increasing attention. Previous studies that have evaluated the Na + -H + antiporter in cells from hypertensive subjects were performed under conditions in which bicarbonate-carbon dioxide (HCO 3 -CO 2 ), the physiological buffer system, was absent from the assay media. This, by design, results in an overestimation of the role of the Na + -H + antiporter in the regulation of intracellular pH (pH|) and ignores the existence of other HCO 3~-dependent transporters that contribute not only to the regulation of pH| 15 -17 but also to the regulation of cell volume, 1819 cell growth, 2021 and intracellular sodium. 22 Alterations in the control of any or all of these processes could in various ways be involved in the pathogenesis of hypertension. 2 - 3910 -23 Received September 10, 1993; accepted in revised form December 21, 1993.From Northwestern University Medical School and Lakeside Veterans Administration Hospital, Chicago, Illinois.Correspondence to Daniel Batlle, MD, Division of Nephrology and Hypertension, Northwestern University Medical School, 310 E Superior, Morton Bldg 3-615, Chicago, IL 60611.changer. Unlike the Na + -H + exchanger and the Na + -independent C1"-HCO 3 " exchanger, which had their highest activities at extremes of pH, (low pH|, Na + -H + exchanger, and high pH, Na + -independent C1"-HCO 3 " exchanger), the Na + -dependent G~-HCO 3~ exchanger had its maximal activity near steady-state pH, (approximately...

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Free cytosolic calcium in renal proximal tubules from the spontaneously hypertensive rat.

Cited by 13 publications

References 35 publications

Reduced intracellular pH in lymphocytes from the spontaneously hypertensive rat.

Reduced intracellular pH in lymphocytes from the spontaneously hypertensive rat.

Early depression of Ankrd2 and Csrp3 mRNAs in the polyribosomal and whole tissue fractions in skeletal muscle with decreased voluntary running

Regulation of intracellular pH in the spontaneously hypertensive rat. Role of bicarbonate-dependent transporters.

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