Differential brain atrial natriuretic peptide expression co-segregates with occurrence of early stroke in the stroke-prone phenotype of the spontaneously hypertensive rat

Neuronal and glial cultures from the hypothalamic-brain stem areas of 1-day-old normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SH) rat brains stained positively with atrial natriuretic peptide (ANP)-specific antibodies. The endogenous levels of the ANP immunoreactivity in WKY neuronal and glial cultures were 17.0 +/- 2.2 and 14.3 +/- 2.7 pg/mg, respectively. Comparable neuronal and glial cultures from SH rat brains contained a 48 to 70% decrease in the endogenous ANP immunoreactivity levels. Culture media from both brain cell types also contained ANP immunoreactivity, the levels of which are significantly higher than those found in the cells. However, similar to endogenous levels, the media levels of immunoreactive ANP in SH neuronal and glial cultures were significantly reduced compared with WKY brain cultures. These observations demonstrate that endogenous ANP-like immunoreactivity is found in neuronal and glial cells and is released into the media. The levels of peptide are reduced in cultures of SH compared with WKY cultures, suggesting a genetically controlled difference between the hypertensive and normotensive rat strains long before hypertension develops.

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Light and electron microscopic localization of atrial natriuretic peptide in the heart of spontaneously hypertensive rat.

Journal of Histochemistry & Cytochemistry ◽

10.1177/36.10.2971091 ◽

1988 ◽

Vol 36 (10) ◽

pp. 1239-1249 ◽

Cited By ~ 17

Author(s):

J A Gu ◽

L Gonzalez-Lavin

Keyword(s):

Atrial Natriuretic Peptide ◽

Natriuretic Peptide ◽

Spontaneously Hypertensive Rat ◽

Peptide Hormone ◽

Electron Microscopic Level ◽

Hypertensive Rats ◽

Electron Microscopic ◽

Spontaneously Hypertensive ◽

Specific Granules ◽

Atrial Natriuretic

Atrial natriuretic peptide (ANP) is a newly discovered peptide hormone present mainly in the atria. We investigated the occurrence and distribution of ANP immunoreactivity in the myocardiocytes of the ventricles of spontaneously hypertensive rats by use of immunocytochemistry at both light and electron microscopic level. ANP immunoreactivity was found in the specific granules in the cytoplasm of the cardiocytes in the subendocardium and the myocardium of the ventricles, as well as in the atria. The specific granules found in the ventricles of hypertensive rats were similar in size, shape, and ANP immunoreactive content to those in the atria. The abundance of ANP immunoreactivity in the left ventricle is greater than that in the right, and appears to increase with increasing severity of hypertension. Conversely, the overall content of ANP in the atria of hypertensive rats was decreased when compared with that in age-matched normotensive rats. The present findings indicate that ventricles may become a major source for ANP synthesis and release during hypertension, and may play important roles in cardiac endocrine pathology and cardiac hypertrophy.

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