DISSOCIATION OF BLOOD PRESSURE AND SYMPATHETIC ACTIVATION OF RENIN RELEASE IN SINOAORTIC-DENERVATED RATS
Authors: Krieger, Marta H; Moreira, Edson D; Oliveira, Edilamar M; Oliveira, Vera LL; Krieger, Eduardo M; Krieger, Jose E
Source: Clinical and Experimental Pharmacology and Physiology, Volume 33, Numbers 5-6, May/June 2006 , pp. 471-476(6)
Publisher: Blackwell Publishing
Key:
- Free Content
- New Content
- Subscribed Content
- Free Trial Content
- Free Content
- New Content
- Subscribed Content
- Free Trial Content
Abstract:
SUMMARY • 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. • 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. • 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). • 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). • 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. • These results show that an elevation in BP appears to offset increased renal sympathetic discharge with no change in PRA.Keywords: neurogenic hypertension; plasma renin activity; renin mRNA; sympathetic hyperactivity
Document Type: Research article
DOI: 10.1111/j.1440-1681.2006.04389.x
Key:
- Free Content
- New Content
- Subscribed Content
- Free Trial Content
- Free Content
- New Content
- Subscribed Content
- Free Trial Content
Click here for Page Help