Catecholamines, angiotensin II and sodium concentrations in cerebrospinal fluid in young men with borderline hypertension

Elevated cerebrospinal fluid sodium in hypertensive human subjects with a family history of Alzheimer's disease

High salt (sodium) intake leads to the development of hypertension despite the fact that plasma sodium concentration ([Na⁺]) is usually normal in hypertensive human patients. Increased cerebrospinal fluid (CSF) sodium contributes to elevated sympathetic activity and high blood pressure (BP) in rodent models of hypertension. However, whether there is an increased accumulation of sodium in the CSF of humans with chronic hypertension is not well defined. Here, we investigated CSF [Na⁺] from hypertensive and normotensive human subjects with family histories of Alzheimer's disease in samples collected in a clinical trial, as spinal tap is not a routine clinical procedure for hypertensive patients. The [Na⁺] and osmolality in plasma and CSF were measured by flame photometry. Daytime ambulatory BP was monitored while individuals were awake. Participants were deidentified and data were analyzed in conjunction with a retrospective analysis of patient history and diagnosis. We found that CSF [Na⁺] was significantly higher in participants with high BP compared with normotensive participants; there was no difference in plasma [Na⁺], or plasma and CSF osmolality between groups. Subsequent multiple linear regression analyses controlling for age, sex, race, and body mass index revealed a significant positive correlation between CSF [Na⁺] and BP but showed no correlation between plasma [Na⁺] and BP. In sum, CSF [Na⁺] was higher in chronic hypertensive individuals and may play a key role in the pathogenesis of human hypertension. Collectively, our findings provide evidence for the clinical significance of CSF [Na⁺] in chronic hypertension in humans.

Chromogranin A immunoreactivity in human cerebrospinal fluid: properties, relationship to noradrenergic neuronal activity, and variation in neurologic disease

Although measurement of chromogranin A in the bloodstream is of value in sympathoadrenal investigations, little is systematically known about chromogranin A in cerebrospinal fluid, despite substantial knowledge about its occurrence and distribution in brain. We therefore applied a homologous human chromogranin A radioimmunoassay to cerebrospinal fluid, in order to evaluate the properties and stability of cerebrospinal fluid chomogranin A, as well as its relationship to central noradrenergic neuronal activity, to peripheral (plasma) chromogranin A, and to disease states such as hypertension, renal failure and Parkinsonism. Authentic, physically stable chromogranin A immunoreactivity was found in cerebrospinal fluid (at 37-146 ng/ml; mean, 87.0 +/- 6.0 ng/ml in healthy subjects), and several lines of evidence (including 3.39 +/- 0.27-fold higher chromogranin A in cerebrospinal fluid than in plasma) indicated that it originated from a local central nervous system source, rather than the periphery. Cerebrospinal fluid chromogranin A values were not influenced by administration of effective antihypertensive doses of clonidine or propranolol, and were not related to the cerebrospinal fluid concentrations of norepinephrine, methoxyhydroxyphenylglycol, or dopamine-beta-hydroxylase; thus, cerebrospinal fluid chromogranin A was not closely linked to biochemical or pharmacologic indices of central noradrenergic neuronal activity. Cerebrospinal fluid chromogranin A was not changed (P > 0.1) in essential hypertension (84.2 +/- 14.0 ng/ml) or renal failure (72.2 +/- 13.4 ng/ml), despite a marked (7.1-fold; P < 0.001) increase in plasma chromogranin A in renal failure, and a modest (1.5-fold; P = 0.004) increase in plasma chromogranin A in essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma catecholamine responses during a personalized physical stress as a dynamic characterization of essential hypertension

High performance liquid chromatography (HPLC) with electrochemical detection proves to be a reliable method for determination of plasma catecholamines (CA) to assess the possible role of the sympathetic nervous system (SNS) in essential hypertension (EH). The present investigation in a group of 15 normotensive (N) and 13 stable EH patients, homogeneous for age and duration of hypertension, was carried out without treatment in the supine position, up-right position and during a personalized bicycle exercise. Mean blood pressure, mean heart rate, plasma renin activity and plasma aldosterone were also evaluated at the various exertion phases. Norepinephrine (NE) and epinephrine (E) showed a progressive increase in N and in EH patients, reaching the highest values at maximum effort. However, EH patients showed higher E plasma levels than N before maximum effort. Dopamine (DA) reached the highest values in N at maximum effort and in EH patients at recovery time. These findings allow us to foresee the possibility of a better characterization of the SNS role in EH.

Atrial natriuretic peptide, angiotensin, norepinephrine and electrolyte in cerebrospinal fluid of essential hypertension

We determined concentrations of atrial natriuretic peptide (ANP), angiotensin (Ang), norepinephrine (NE) and electrolyte in plasma and cerebrospinal fluid (CSF) to study possible roles of these substances within the brain in human hypertension. Blood and CSF samples were obtained from 10 patients with mild to moderate essential hypertension (EHT) aged 40-65 y and 10 age-matched normotensive subjects (NT) on a regular salt diet (8 g/day). Levels of ANP, NE, Na, K, Ca and Cl in CSF and plasma were comparable between EHT and NT. Plasma renin activity, plasma and CSF Ang II were lower in EHT than NT. CSF Ang III tended to be lower in EHT. There was no correlation between CSF and plasma ANP, or between CSF and plasma Ang II. Our results indicate that CSF levels of ANP may not be altered in middle aged patients with mild to moderate hypertension. It is also suggested that Ang II, NE and sodium in the central nervous system may not have important roles in hypertension of those patients.