Effect of Chronic Intermittent Hypoxia on Angiotensin II Receptors in the Central Nervous System
| Autor: | Morgan Rothman, Ann Mitzey, John M. Dopp, Robert C. Speth, Barbara J. Morgan, Nicole Schrimpf, Mark S. Brownfield |
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| Rok vydání: | 2018 |
| Předmět: |
medicine.medical_specialty
Sympathetic nervous system Angiotensin receptor Physiology Chemistry Central nervous system Intermittent hypoxia General Medicine Rostral ventrolateral medulla 030204 cardiovascular system & hematology Angiotensin II 03 medical and health sciences 0302 clinical medicine medicine.anatomical_structure Endocrinology Hypothalamus Internal medicine Internal Medicine medicine 030212 general & internal medicine Receptor |
| Zdroj: | Clinical and Experimental Hypertension. 41:130-136 |
| ISSN: | 1525-6006 1064-1963 |
| Popis: | Chronic intermittent hypoxia (CIH) increases basal sympathetic nervous system activity, augments chemoreflex-induced sympathoexcitation, and raises blood pressure. All effects are attenuated by systemic or intracerebroventricular administration of angiotensin II type 1 receptor (AT1R) antagonists. This study aimed to quantify the effects of CIH on AT1R- and AT2R-like immunoreactivity in the rostroventrolateral medulla (RVLM) and paraventricular nucleus of the hypothalamus (PVN), central regions that are important components of the extended chemoreflex pathway. Eighteen Sprague-Dawley rats were exposed to intermittent hypoxia (FIO2 = 0.10, 1 min at 4-min intervals) for 10 hr/day for 1, 5, 10, or 21 days. After exposure, rats were deeply anesthetized and transcardially perfused with phosphate buffered saline (PBS) followed by 4% paraformaldehyde in PBS. Brains were removed and sectioned coronally into 50 µm slices. Immunohistochemistry was used to quantify AT1R and AT2R in the RVLM and the PVN. In the RVLM, CIH significantly increased the AT1R-like immunoreactivity, but did not alter AT2R immunoreactivity, thereby augmenting the AT1R:AT2R ratio in this nucleus. In the PVN, CIH had no effect on immunoreactivity of either receptor subtype. The current findings provide mechanistic insight into increased basal sympathetic outflow, enhanced chemoreflex sensitivity, and blood pressure elevation observed in rodents exposed to CIH. |
| Databáze: | OpenAIRE |
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