An aldosterone-related system in the ventrolateral medulla oblongata of spontaneously hypertensive and Wistar-Kyoto rats

Natasha N. Kumar, Ann K. Goodchild, Qun Li, Paul M. Pilowsky

Research output: Contribution to journalArticleResearchpeer-review

Abstract

1. The actions of aldosterone include mediation of vasoconstriction, vascular fibrosis, endothelial dysfunction and sodium retention. These actions can contribute to hypertension. Recent studies implicate an abnormal aldosterone hormonal system in the brain in hypertension. However, the study of central aldosterone actions is still in its infancy, as the exact location and abundance of its components in the brain are uncertain. 2. We aimed to detect components of the aldosterone cascade in the regions of the ventrolateral medulla oblongata (VLM)-containing neurons that regulate blood pressure and to see whether there are quantitative differences in these components between the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat models. Tissues from four regions of the brainstem, namely, the rostral and caudal ventrolateral medulla (RVLM and CVLM, respectively), rostral pressor area and caudal pressor area, were examined. We measured mRNA expression of aldosterone synthase, mineralocorticoid receptor (MR1), 12-lipoxygenase (12-LO), serum- and glucocorticoid- inducible kinase and K-ras in male rats. Gene expression levels were measured using real-time reverse transcription-polymerase chain reaction. 3. We detected all aldosterone components in all regions of the VLM. The K-ras levels were not significantly different in any of the regions. Expression of MR1 mRNA was lower in the RVLM of SHR (n = 5) compared with WKY rats (n = 5; t = 4.590; P = 0.002) and 12-LO mRNA levels were lower in the CVLM in SHR (n = 6) compared with WKY rats (n = 7; P = 0.04). Thus, we have shown for the first time that components of the aldosterone cascade are present in the VLM. Our results suggest that there may be a differential gene expression profile in the brainstem for genetic hypertension.

LanguageEnglish
Pages71-75
Number of pages5
JournalClinical and Experimental Pharmacology and Physiology
Volume33
Issue number1-2
DOIs
Publication statusPublished - Jan 2006

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Medulla Oblongata
Inbred WKY Rats
Aldosterone
Inbred SHR Rats
Arachidonate 12-Lipoxygenase
Hypertension
Messenger RNA
Brain Stem
Cytochrome P-450 CYP11B2
Mineralocorticoid Receptors
Brain
Vasoconstriction
Transcriptome
Glucocorticoids
Reverse Transcription
Blood Vessels
Fibrosis
Sodium
Blood Pressure
Gene Expression

Cite this

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title = "An aldosterone-related system in the ventrolateral medulla oblongata of spontaneously hypertensive and Wistar-Kyoto rats",
abstract = "1. The actions of aldosterone include mediation of vasoconstriction, vascular fibrosis, endothelial dysfunction and sodium retention. These actions can contribute to hypertension. Recent studies implicate an abnormal aldosterone hormonal system in the brain in hypertension. However, the study of central aldosterone actions is still in its infancy, as the exact location and abundance of its components in the brain are uncertain. 2. We aimed to detect components of the aldosterone cascade in the regions of the ventrolateral medulla oblongata (VLM)-containing neurons that regulate blood pressure and to see whether there are quantitative differences in these components between the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat models. Tissues from four regions of the brainstem, namely, the rostral and caudal ventrolateral medulla (RVLM and CVLM, respectively), rostral pressor area and caudal pressor area, were examined. We measured mRNA expression of aldosterone synthase, mineralocorticoid receptor (MR1), 12-lipoxygenase (12-LO), serum- and glucocorticoid- inducible kinase and K-ras in male rats. Gene expression levels were measured using real-time reverse transcription-polymerase chain reaction. 3. We detected all aldosterone components in all regions of the VLM. The K-ras levels were not significantly different in any of the regions. Expression of MR1 mRNA was lower in the RVLM of SHR (n = 5) compared with WKY rats (n = 5; t = 4.590; P = 0.002) and 12-LO mRNA levels were lower in the CVLM in SHR (n = 6) compared with WKY rats (n = 7; P = 0.04). Thus, we have shown for the first time that components of the aldosterone cascade are present in the VLM. Our results suggest that there may be a differential gene expression profile in the brainstem for genetic hypertension.",
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An aldosterone-related system in the ventrolateral medulla oblongata of spontaneously hypertensive and Wistar-Kyoto rats. / Kumar, Natasha N.; Goodchild, Ann K.; Li, Qun; Pilowsky, Paul M.

In: Clinical and Experimental Pharmacology and Physiology, Vol. 33, No. 1-2, 01.2006, p. 71-75.

Research output: Contribution to journalArticleResearchpeer-review

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