摘要:

Groups of 15 rats were injected subcutaneously with a microcrystailine suspension of DOCA and given 1% saline as drinking water for periods ranging from 2 to 16 days. Thein vivotransmembrane distribution of Na and K in relation to blood pressure was assessed in terms of plasma [Na] and [K] measured with ion-specific electrodes; smooth muscle cell Na; K and water were measured in the rapidly excised tail artery. A small increase in blood pressure was observed in week 1 of treatment and was followed by an abrupt increase to higher levels at about day 10. Plasma [Na] was elevated and [K] lowered throughout in a new steady state with a reciprocal change of about 1 mmol/l. There were minor changes in intracellular [K] in rapidly excised fresh tail artery samples so that the transmembrane K gradient (EK) was at all times increased by > 10 mV, indicating enhanced Na—K transport. In general, intracellular [Na] was directly and Na gradient inversely related to blood pressure (P< 0.01).

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Relationships between cytosolic free calcium ([Ca2+]i) in platelets, indices of systemic calcium metabolism and blood pressure were examined in 86 subjects; 29 patients with untreated and 29 patients with treated essential hypertension, six patients with borderline hypertension and 22 healthy reference subjects. In order to analyse interactions between the variables, multivariate statistical analyses were employed.The patients with untreated hypertension had higher [Ca2+]ivalues in non-activated platelets (P= 0.04) and lower levels of plasma ionized calcium (P= 0.02) than the reference subjects. In multivariate models analysing platelet [Ca2+]imean blood pressure (MBP), plasma ionized calcium, serum parathyroid hormone (PTH) and body mass index (BMI), the relationship between platelet [Ca2+]iand blood pressure was attenuated (P= 0.13), whereas the inverse relationships between plasma ionized calcium and MBP (P= 0.01) and between platelet [Ca2+]iand serum PTH (P= 0.06) seen in univariate analyses persisted.According to the multivariate models the [Ca2+]ivalue explained only 5% of the MBP variability. Thus, the data from this investigation do not support a close relationship between basal platelet [Ca2+]iand blood pressure. The inverse relationship between plasma ionized calcium and blood pressure, independent of platelet [Ca2+]iand serum PTH, suggests a direct interaction between plasma ionized calcium and blood pressure regulation.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

We studied the density of the angiotensin II (Ang II) binding site in discrete brain nuclei of 4-week-old and 14-week-old spontaneously hypertensive rats (SHR) and agematched normotensive Wistar-Kyoto (WKY) control rats by autoradiographic binding techniques. Tissue sections were incubatedin vitrowith 3 nmol/l [125I]Sar1Ang and results were analysed by computerized microdensitometry and by comparison with125I-standards.Both young and adult SHR (aged 4 and 14 weeks, respectively) had significantly higher Ang II binding site concentrations in the median preoptic nucleus (MPO), subfornical organ (SFO), paraventricular nucleus (PVN) and nucleus of the solitary tract (NTS) when compared to age-matched WKY control rats. No significant difference was found between strains in other brain areas such as the olfactory bulb, suprachiasmatic nucleus (SCh), inferior olive (IO) and area postrema (AP).It was observed that the concentration of Ang II binding sites increased with age in PVN of both SHR and WKY, while the number of binding sites in the MPO and IO decreased with age.In SHR, alteration in Ang II binding is restricted to brain nuclei involved in the central pressor action of Ang II and seems to be related to the development and maintenance of spontaneous hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID