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Fardin NM, Antonio EL, Montemor JAS, da Veiga GL, Tucci PJF, Campos RR. Digitoxin improves cardiovascular autonomic control in rats with heart failure. Can J Physiol Pharmacol 2016; 94:643-50. [DOI: 10.1139/cjpp-2015-0354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of chronic treatment with digitoxin on arterial baroreceptor sensitivity for heart rate (HR) and renal sympathetic nerve activity (rSNA) control, cardiopulmonary reflex, and autonomic HR control in an animal model of heart failure (HF) were evaluated. Wistar rats were treated with digitoxin, which was administered in their daily feed (1 mg/kg per day) for 60 days. The following 3 experimental groups were evaluated: sham, HF, and HF treated with digitoxin (HF + DIG). We observed an increase in rSNA in the HF group (190 ± 29 pps, n = 5) compared with the sham group (98 ± 14 pps, n = 5). Digitoxin treatment prevented an increase in rSNA (98 ± 14 pps, n = 7). Therefore, arterial baroreceptor sensitivity was decreased in the HF group (−1.24 ± 0.07 bpm/mm Hg, n = 8) compared with the sham group (−2.27 ± 0.23 bpm/mm Hg, n = 6). Digitoxin did not alter arterial baroreceptor sensitivity in the HF + DIG group. Finally, the HF group showed an increased low frequency band (LFb: 23 ± 5 ms2, n = 8) and a decreased high frequency band (HFb: 77 ± 5 ms2, n = 8) compared with the sham group (LFb: 14 ± 3 ms2; HFb: 86 ± 3 ms2, n = 9); the HF+DIG group exhibited normalized parameters (LFb: 15 ± 3 ms2; HFb: 85 ± 3 ms2, n = 9). In conclusion, the benefits of decreasing rSNA are not directly related to improvements in peripheral cardiovascular reflexes; such occurrences are due in part to changes in the central nuclei of the brain responsible for autonomic cardiovascular control.
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Affiliation(s)
- Núbia Mantovan Fardin
- Cardiovascular Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, CEP 04023-060, São Paulo, SP, Brazil
| | - Ednei Luiz Antonio
- Cardiology Division, Department of Medicine, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | | | - Glaucia Luciano da Veiga
- Cardiovascular Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, CEP 04023-060, São Paulo, SP, Brazil
| | - Paulo José Ferreira Tucci
- Cardiology Division, Department of Medicine, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Ruy R. Campos
- Cardiovascular Division, Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, CEP 04023-060, São Paulo, SP, Brazil
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