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Cardiac sympathetic overactivity and decreased baroreflex sensitivity in l-NAME hypertensive rats
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| Zeitschriftentitel: | American Journal of Physiology-Heart and Circulatory Physiology |
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| Personen und Körperschaften: | , , , , |
| In: | American Journal of Physiology-Heart and Circulatory Physiology, 280, 2001, 2, S. H844-H850 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Physiological Society
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| Schlagwörter: |
| Zusammenfassung: | <jats:p> The present study evaluated the possible changes in the autonomic control of heart rate in the hypertensive model induced by the inhibition of nitric oxide synthase. Rats were treated with N <jats:sup>G</jats:sup>-nitro-l-arginine methyl ester (l-NAME group) in the drinking water during 7 days, whereas control groups were treated with tap water (control group) or with the N <jats:sup>G</jats:sup>-nitro-d-arginine methyl ester (d-NAME group), an inactive isomer of thel-NAME molecule. The l-NAME group developed hypertension and tachycardia. The sequential blockade of the autonomic influences with propranolol and methylatropine indicated that the intrinsic heart rate did not differ among groups and revealed a sympathetic overactivity in the control of heart rate in thel-NAME group. The spectral density power of heart rate, calculated using fast-Fourier transformation, indicated a reduced variability in the low-frequency band (0.20–0.60 Hz) for thel-NAME group. The baroreflex sensitivity was also attenuated in these animals when compared with the normotensive control or d-NAME group. Overall, these data indicate cardiac sympathetic overactivity associated with a decreased baroreflex sensitivity in l-NAME hypertensive rats. </jats:p> |
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| Umfang: | H844-H850 |
| ISSN: |
0363-6135
1522-1539 |
| DOI: | 10.1152/ajpheart.2001.280.2.h844 |