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Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat
Experiments were designed to test the hypothesis that median preoptic (MnPO) neurons are necessary for the full hypertensive response to chronic angiotensin II (AngII) in rats consuming a high salt diet. The MnPO is implicated in many of the physiologic actions of AngII, primarily acting as a downst...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788964/ https://www.ncbi.nlm.nih.gov/pubmed/36564179 http://dx.doi.org/10.14814/phy2.15551 |
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author | Collister, John P. Ployngam, Trasida Ariza‐Guzman, Pilar A. Osborn, John W. |
author_facet | Collister, John P. Ployngam, Trasida Ariza‐Guzman, Pilar A. Osborn, John W. |
author_sort | Collister, John P. |
collection | PubMed |
description | Experiments were designed to test the hypothesis that median preoptic (MnPO) neurons are necessary for the full hypertensive response to chronic angiotensin II (AngII) in rats consuming a high salt diet. The MnPO is implicated in many of the physiologic actions of AngII, primarily acting as a downstream nucleus to AngII binding at circumventricular organs such as the organum vasculosum of the lamina terminalis (OVLT). We have previously shown a prominent effect of lesion of the OVLT on the chronic hypertensive effects of AngII in rats consuming high salt. Additionally, we have shown that lesion of the MnPO attenuated the hypertensive response to chronic intravenous infusion of AngII in rats. However, whether MnPO neurons or fibers of passage contribute to this response is not clear. Male Sprague Dawley rats were randomly assigned to either sham (SHAM; n = 8) or ibotenic acid lesion of the MnPO (MnPOx; n = 6). In the MnPOx group, 200 nl of ibotenic acid in phosphate buffer saline (5 μg/μl) was injected into each of 3 predetermined coordinates targeted at the entire MnPO. After a week of recovery, rats were instrumented with radiotelemetric pressure transducers, provided 2.0% NaCl diet and distilled water ad libitum and given another week to recover. After 3 days of baseline measurements, osmotic minipumps were implanted subcutaneously in all rats for administration of AngII at a rate of 150 ng/kg/min. Blood pressure measurements were made for 14 days after minipump implantation. By day 7 of AngII treatment, blood pressure responses appeared to plateau in both groups while the hypertensive response was markedly attenuated in MnPOx rats (MnPOx, 122 ± 6 mmHg; SHAM, 143 ± 8 mmHg). These results support the hypothesis that neurons of the MnPO are involved in the central pathway mediating the chronic hypertensive effects of AngII in rats consuming a high salt diet. |
format | Online Article Text |
id | pubmed-9788964 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-97889642022-12-28 Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat Collister, John P. Ployngam, Trasida Ariza‐Guzman, Pilar A. Osborn, John W. Physiol Rep Original Articles Experiments were designed to test the hypothesis that median preoptic (MnPO) neurons are necessary for the full hypertensive response to chronic angiotensin II (AngII) in rats consuming a high salt diet. The MnPO is implicated in many of the physiologic actions of AngII, primarily acting as a downstream nucleus to AngII binding at circumventricular organs such as the organum vasculosum of the lamina terminalis (OVLT). We have previously shown a prominent effect of lesion of the OVLT on the chronic hypertensive effects of AngII in rats consuming high salt. Additionally, we have shown that lesion of the MnPO attenuated the hypertensive response to chronic intravenous infusion of AngII in rats. However, whether MnPO neurons or fibers of passage contribute to this response is not clear. Male Sprague Dawley rats were randomly assigned to either sham (SHAM; n = 8) or ibotenic acid lesion of the MnPO (MnPOx; n = 6). In the MnPOx group, 200 nl of ibotenic acid in phosphate buffer saline (5 μg/μl) was injected into each of 3 predetermined coordinates targeted at the entire MnPO. After a week of recovery, rats were instrumented with radiotelemetric pressure transducers, provided 2.0% NaCl diet and distilled water ad libitum and given another week to recover. After 3 days of baseline measurements, osmotic minipumps were implanted subcutaneously in all rats for administration of AngII at a rate of 150 ng/kg/min. Blood pressure measurements were made for 14 days after minipump implantation. By day 7 of AngII treatment, blood pressure responses appeared to plateau in both groups while the hypertensive response was markedly attenuated in MnPOx rats (MnPOx, 122 ± 6 mmHg; SHAM, 143 ± 8 mmHg). These results support the hypothesis that neurons of the MnPO are involved in the central pathway mediating the chronic hypertensive effects of AngII in rats consuming a high salt diet. John Wiley and Sons Inc. 2022-12-23 /pmc/articles/PMC9788964/ /pubmed/36564179 http://dx.doi.org/10.14814/phy2.15551 Text en © 2022 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Articles Collister, John P. Ployngam, Trasida Ariza‐Guzman, Pilar A. Osborn, John W. Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat |
title | Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat |
title_full | Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat |
title_fullStr | Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat |
title_full_unstemmed | Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat |
title_short | Neurons of the median preoptic nucleus contribute to chronic angiotensin II‐salt induced hypertension in the rat |
title_sort | neurons of the median preoptic nucleus contribute to chronic angiotensin ii‐salt induced hypertension in the rat |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788964/ https://www.ncbi.nlm.nih.gov/pubmed/36564179 http://dx.doi.org/10.14814/phy2.15551 |
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