Dietary sodium intake: Influence on calcium channels and urinary calcium excretion in spontaneously hypertensive rats

Galletti, Ferruccio; Rutledge, A.; Triggle, David J.

doi:10.1016/0006-2952(91)90193-9

Cited by 10 publications

(6 citation statements)

References 22 publications

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“…In the present study, SHR rats were heavier than WKY rats, in agreement with the findings of several other studies (Schedl et al 1984;Hatton et al 1989;Pörsti, 1992). However, other studies have reported that WKY rats were heavier than SHR rats (Lau et al 1984;Izawa et al 1985;Galletti et al 1991;Touyz & Milne, 1999;Pezeshk & Dalhouse, 2000;Vasedv et al 2000). The reasons for this discrepancy between studies are not clear.…”

Section: Effect Of Dietary Intervention To Stop Hypertension-type Diesupporting

confidence: 93%

The effect of nutrient profiles of the Dietary Approaches to Stop Hypertension (DASH) diets on blood pressure and bone metabolism and composition in normotensive and hypertensive rats

Doyle

Cashman

2003

Br J Nutr

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Hypertension has been associated with abnormalities of Ca and bone metabolism. Consequently, dietary strategies aimed at reducing blood pressure may also benefit bone health; however, this issue has received little attention. Therefore, the objective of the present study was to investigate the effect of two antihypertensive-type diets on blood pressure and bone metabolism and composition in normotensive (Wistar-Kyoto NHsd, WKY) and hypertensive (spontaneously hypertensive NHsd, SHR) rats. Thirty WKY and thirty SHR male rats, 14 weeks old, were separately randomized by weight into three groups of ten rats each. One group from each strain was given a control diet while the other two groups were fed two anti-hypertensive (high fruit and vegetable (F/V) and high fruit and vegetable and low-fat dairy produce (combination)) diets for 8 weeks. SHR rats were significantly (P,0·01) heavier than WKY rats. Blood pressure and femoral length, width, dry weight, ash, Ca, Mg, P and bone mineral mass were significantly (P, 0·0001) greater in SHR than WKY rats, but were unaffected by diet, irrespective of strain. While markers of bone formation (serum osteocalcin) and bone resorption (urinary pyridinoline and deoxypyridinoline) were similar in both strains, these markers were significantly (P, 0·05) lower (28 -31, 16 -23, 31 -33 % respectively) in the SHR rats fed the combination diet relative to those fed the control and F/V diets. Bone turnover in WKY rats was unaffected by diet. In conclusion, these findings suggest that the combination diet may benefit bone metabolism in hypertensive animals. However, as blood pressure was unaffected by this diet, the mechanism by which it reduced bone turnover requires further investigation.

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Section: Effect Of Dietary Intervention To Stop Hypertension-type Diesupporting

confidence: 93%

The effect of nutrient profiles of the Dietary Approaches to Stop Hypertension (DASH) diets on blood pressure and bone metabolism and composition in normotensive and hypertensive rats

Doyle

Cashman

2003

Br J Nutr

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“…The relationship between calcium intake and sodium intake has been investigated in detail, in part because of the known link between calcium and sodium excretion (e.g., Refs. 34, 99,148,215), and in part because of the involvement of both calcium and sodium in hypertension (see reviews in Refs. 115,186,231,276).…”

Section: Sodiummentioning

confidence: 99%

Calcium: Taste, Intake, and Appetite

Tordoff

2001

Physiological Reviews

159

106

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This review summarizes research on sensory and behavioral aspects of calcium homeostasis. These are fragmented fields, with essentially independent lines of research involving gustatory electrophysiology in amphibians, ethological studies in wild birds, nutritional studies in poultry, and experimental behavioral studies focused primarily on characterizing the specificity of the appetite in rats. Recently, investigators have begun to examine potential physiological mechanisms underlying calcium intake and appetite. These include changes in the taste perception of calcium, signals related to blood calcium concentrations, and actions of the primary hormones of calcium homeostasis: parathyroid hormone, calcitonin, and 1,25-dihydroxyvitamin D. Other influences on calcium intake include reproductive and adrenal hormones and learning. The possibility that a calcium appetite exists in humans is discussed. The broad range of observations documenting the existence of a behavioral limb of calcium homeostasis provides a strong foundation for future genetic and physiological analyses of this behavior.

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“…In adult SHR, high salt intake increases cardiac dihydropyridine binding sites. 19 Further studies are needed to examine whether in SHR high salt intake also increases brain binding sites for dihydropyridines, leading to enhanced responses to intracerebroventricular nifedipine.…”

Section: Discussionmentioning

confidence: 99%

Sympathoinhibitory Effects of Central Nifedipine in Spontaneously Hypertensive Rats on High Versus Regular Sodium Intake

Huang¹,

Leenen²

1999

Hypertension

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Abstract-The putative central sympathoinhibitory actions of the dihydropyridine calcium antagonist nifedipine and the effect of dietary sodium on these actions were investigated in spontaneously hypertensive rats (SHR). Regular or high dietary salt was administered from 4 to 8 weeks of age. At 8 weeks, blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity were recorded in conscious rats at rest as well as in response to intravenous (50 g/kg) and intracerebroventricular (5 and 50 g/kg) injections of nifedipine and intracerebroventricular injections of vehicle. Resting mean arterial pressure was higher in SHR on high versus regular salt (159Ϯ3 versus 135Ϯ4 mm Hg; PϽ0.05). Nifedipine administered intracerebroventricularly decreased BP as well as renal sympathetic nerve activity and HR in a dose-related manner. The responses reached their peak at 3 to 5 minutes and lasted Ϸ30 minutes. Peak decreases in BP, renal sympathetic nerve activity, and HR in response to both doses of nifedipine were significantly larger in SHR on high versus regular salt. Nifedipine administered intravenously also decreased BP but, in contrast, caused (reflex) increases in renal sympathetic nerve activity and HR. On both diets, intracerebroventricular vehicle did not affect mean arterial pressure, renal sympathetic nerve activity, or HR. These data indicate that in contrast to its peripheral vasodilator effect, centrally administered nifedipine may decrease sympathetic outflow and therefore BP and HR. The enhanced sympathoinhibitory and depressor responses to nifedipine in SHR on high versus regular salt suggest that the sympathetic hyperactivity induced by high salt intake is dependent on neuronal calcium influx via L-type channels. (Hypertension. 1999;33:32-35.)Key Words: nifedipine Ⅲ dihydropyridines Ⅲ nervous system, sympathetic Ⅲ hypertension Ⅲ rats, inbred SHR Ⅲ sodium, dietary A n increase in Ca 2ϩ influx triggers a variety of cellular functions, such as increased cardiac and smooth muscle contractility, endocrine gland secretion, and neurotransmitter release. 1 Dihydropyridines such as nifedipine inhibit Ca 2ϩ influx through voltage-sensitive calcium channels. 2 The effects of calcium antagonists on sympathetic activity have thus far been related mainly to reflex responses after rapid lowering of blood pressure (BP) induced by rapidly acting calcium antagonists 3 and perhaps presynaptic effects. 4 Although receptors for calcium antagonists 5 as well as calcium antagonist-sensitive calcium channels 6 have been demonstrated in the brain, little is known regarding direct central effects of Ca 2ϩ antagonists on sympathetic activity and central control of circulation.In vitro, dihydropyridine-sensitive Ca 2ϩ channels exist in rat hypothalamus. 6 The stimulus-induced high-frequency activity in brain cells is carried by L-type but not T-type Ca 2ϩ channels, 7 and a dihydropyridine such as nifedipine is a potent L-but not T-type channel antagonist. 8 Although centrally administered calcium antagonists have been reported ...

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Dietary sodium intake: Influence on calcium channels and urinary calcium excretion in spontaneously hypertensive rats

Cited by 10 publications

References 22 publications

The effect of nutrient profiles of the Dietary Approaches to Stop Hypertension (DASH) diets on blood pressure and bone metabolism and composition in normotensive and hypertensive rats

The effect of nutrient profiles of the Dietary Approaches to Stop Hypertension (DASH) diets on blood pressure and bone metabolism and composition in normotensive and hypertensive rats

Calcium: Taste, Intake, and Appetite

Sympathoinhibitory Effects of Central Nifedipine in Spontaneously Hypertensive Rats on High Versus Regular Sodium Intake

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