Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat
Recent studies in prehypertensive spontaneously hypertensive rats (SHR) have shown larger calcium transients and reduced norepinephrine transporter (NET) activity in cultured stellate neurons compared with Wistar-Kyoto (WKY) controls, although the functional significance of these results is unknown....
| Автори: | , , , , , |
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| Формат: | Journal article |
| Мова: | English |
| Опубліковано: |
American Physiological Society
2013
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| _version_ | 1826276568485330944 |
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| author | Shanks, J Herring, N Manou-Stathopoulou, S Lu, C Li, D Paterson, D |
| author_facet | Shanks, J Herring, N Manou-Stathopoulou, S Lu, C Li, D Paterson, D |
| author_sort | Shanks, J |
| collection | OXFORD |
| description | Recent studies in prehypertensive spontaneously hypertensive rats (SHR) have shown larger calcium transients and reduced norepinephrine transporter (NET) activity in cultured stellate neurons compared with Wistar-Kyoto (WKY) controls, although the functional significance of these results is unknown. We hypothesized that peripheral sympathetic responsiveness in the SHR at 4 wk of age would be exaggerated compared with the WKY. In vivo arterial pressure (under 2% isoflurane) was similar in SHRs (88 ± 2/50 ± 3 mmHg, n = 18) compared with WKYs (88 ± 3/49 ± 4 mmHg, n = 20). However, a small but significant (P < 0.05) tachycardia was observed in the young SHR despite the heart rate response to vagus stimulation (3 and 5 Hz) in vivo being similar (SHR: n = 12, WKY: n = 10). In isolated atrial preparations there was a significantly greater tachycardia during right stellate stimulation (5 and 7 Hz) in SHRs (n = 19) compared with WKYs (n = 16) but not in response to exogenous NE (0.025–5 μM, SHR: n = 10, WKY: n = 10). There was also a significantly greater release of [3H]NE to field stimulation (5 Hz) of atria in the SHR (SHR: n = 17, WKY: n = 16). Additionally, plasma levels of neuropeptide Y sampled from the right atria in vivo were also higher in the SHR (ELISA, n = 12 for both groups). The difference in [3H]NE release between SHR and WKY could be normalized by the NET inhibitor desipramine (1 μM, SHR: n = 10, WKY: n = 8) but not the α2-receptor antagonist yohimbine (1 μM, SHR: n = 7, WKY: n = 8). Increased cardiac sympathetic neurotransmission driven by larger neuronal calcium transients and reduced NE reuptake translates into enhanced cardiac sympathetic responsiveness at the end organ in prehypertensive SHRs. |
| first_indexed | 2024-03-06T23:15:55Z |
| format | Journal article |
| id | oxford-uuid:671ea6b9-b83d-42a5-92d0-13365ae8c63f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T23:15:55Z |
| publishDate | 2013 |
| publisher | American Physiological Society |
| record_format | dspace |
| spelling | oxford-uuid:671ea6b9-b83d-42a5-92d0-13365ae8c63f2022-03-26T18:36:17ZCardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive ratJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:671ea6b9-b83d-42a5-92d0-13365ae8c63fEnglishSymplectic Elements at OxfordAmerican Physiological Society2013Shanks, JHerring, NManou-Stathopoulou, SLu, CLi, DPaterson, DRecent studies in prehypertensive spontaneously hypertensive rats (SHR) have shown larger calcium transients and reduced norepinephrine transporter (NET) activity in cultured stellate neurons compared with Wistar-Kyoto (WKY) controls, although the functional significance of these results is unknown. We hypothesized that peripheral sympathetic responsiveness in the SHR at 4 wk of age would be exaggerated compared with the WKY. In vivo arterial pressure (under 2% isoflurane) was similar in SHRs (88 ± 2/50 ± 3 mmHg, n = 18) compared with WKYs (88 ± 3/49 ± 4 mmHg, n = 20). However, a small but significant (P < 0.05) tachycardia was observed in the young SHR despite the heart rate response to vagus stimulation (3 and 5 Hz) in vivo being similar (SHR: n = 12, WKY: n = 10). In isolated atrial preparations there was a significantly greater tachycardia during right stellate stimulation (5 and 7 Hz) in SHRs (n = 19) compared with WKYs (n = 16) but not in response to exogenous NE (0.025–5 μM, SHR: n = 10, WKY: n = 10). There was also a significantly greater release of [3H]NE to field stimulation (5 Hz) of atria in the SHR (SHR: n = 17, WKY: n = 16). Additionally, plasma levels of neuropeptide Y sampled from the right atria in vivo were also higher in the SHR (ELISA, n = 12 for both groups). The difference in [3H]NE release between SHR and WKY could be normalized by the NET inhibitor desipramine (1 μM, SHR: n = 10, WKY: n = 8) but not the α2-receptor antagonist yohimbine (1 μM, SHR: n = 7, WKY: n = 8). Increased cardiac sympathetic neurotransmission driven by larger neuronal calcium transients and reduced NE reuptake translates into enhanced cardiac sympathetic responsiveness at the end organ in prehypertensive SHRs. |
| spellingShingle | Shanks, J Herring, N Manou-Stathopoulou, S Lu, C Li, D Paterson, D Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
| title | Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
| title_full | Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
| title_fullStr | Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
| title_full_unstemmed | Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
| title_short | Cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
| title_sort | cardiac sympathetic dysfunction in the prehypertensive spontaneously hypertensive rat |
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