Produção Nacional
Revisado por pares
DISSOCIATION OF BLOOD PRESSURE AND SYMPATHETIC ACTIVATION OF RENIN RELEASE IN SINOAORTIC‐DENERVATED RATS
2006; Wiley; Volume: 33; Issue: 5-6 Linguagem: Inglês
10.1111/j.1440-1681.2006.04389.x
ISSN1440-1681
AutoresMarta Helena Krieger, Edson Duarte Moreira, Edilamar Menezes de Oliveira, V L Oliveira, Eduardo Moacyr Krieger, José Eduardo Krieger,
Tópico(s)Regulation of Appetite and Obesity
Resumo1 Blood pressure (BP) and heart rate (HR) increase 6 and 24 h after sinoaortic baroreceptor denervation (SAD), whereas plasma renin activity (PRA) and renal renin mRNA levels remain unchanged. We postulated that a simultaneous rise in BP could offset the expected activation of renin associated with an increased renal sympathetic discharge secondary to SAD. 2 To test this hypothesis, the increase in BP associated with the onset of SAD was prevented by a continuous infusion of sodium nitroprusside (SNP; 30 mg/kg per h). Changes were measured in five groups of conscious adult male Wistar rats: (i) sham; (ii) SAD; (iii) SAD rats in which the BP was prevented from increasing by infusion of SNP; (iv) sham rats in which the BP was increased by 30% by infusion of phenylephrine (PE; 1.5–2.0 mL/h); and (v) SNP + PE for 3 h by infusion as above. 3 As expected, BP and heart rate (HR) increased significantly following SAD compared with sham rats (152 ± 4 vs 116 ± 3 mmHg, respectively, for BP and 503 ± 6 vs 345 ± 13 b.p.m., respectively for HR; n = 5; P < 0.05) but remained unchanged when SNP was infused for 3 h (106 ± 1 mmHg and 455 ± 9 b.p.m., respectively; n = 5; P < 0.05). 4 Similarly, BP and HR increased with PE infusion compared with PE + SNP (138 ± 9.9 vs 113 ± 2.3 mmHg for BP, respectively, and 325 ± 9 vs 423 ± 18 b.p.m. for HR, respectively; n = 5; P < 0.05). 5 Plasma renin activity remained unchanged in SAD compared with sham rats (1.67 ± 0.35 vs 1.05 ± 0.17 ng angiotensin (Ang) I/mL per h), but increased significantly when hypertension was prevented (5.86 ± 0.77 ng AngI/mL per h; n = 5; P < 0.05). Renin mRNA levels in the kidneys were unchanged in all groups. 6 These results show that an elevation in BP appears to offset increased renal sympathetic discharge with no change in PRA.
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