• Home
  • Search Results
  • Cardiac autonomic balance in rats submitted to protein restriction after weaning.

Cardiac autonomic balance in rats submitted to protein restriction after weaning.

Clinical and experimental pharmacology & physiology (2010-12-15)
Carlito D D Martins, Deoclécio A Chianca, Luciano G Fernandes
ABSTRACT

1. In the present study, we evaluated the autonomic balance of the heart in protein/energy-undernourished rats. 2. Rats were divided into two groups according to the diet they received after weaning: (i) the control group (n=16), given a 15% protein diet, and (ii) the malnourished group (n=14), fed a 6% protein diet. Cardiovascular recordings were made and, through selective autonomic blockade, the tonic autonomic balance, cardiac autonomic index and the power spectrum of heart rate (HR) variability were determined. 3. Muscarinic receptor blockade with methylatropine (5.0 mg/kg, i.v.) increased HR in the control group (371 ± 6 vs 427 ± 15 b.p.m. before and after drug administration, respectively), but not the malnourished group (438 ± 24 vs 472 ± 38 b.p.m. before and after drug administration, respectively). Inhibition of β(1)-adrenoceptors with metoprolol (2.0 mg/kg, i.v.) reduced HR in malnourished rats (428 ± 24 vs 355 ± 16 b.p.m. before and after drug administration, respectively), but had no effect on the HR of the control group (363 ± 8 vs 362 ± 7 b.p.m. before and after drug administration, respectively). Double autonomic blockade by inhibiting both muscarinic cholinoceptors and β(1)-adrenoceptors reduced HR in the malnourished group (428 ± 24 vs 342 ± 14 b.p.m.) but had no effect on HR in the control group (371 ± 6 vs 382 ± 6 b.p.m.). 4. Sympathetic tone was augmented in malnourished compared with control rats (131 ± 17 vs 41 ± 11 b.p.m., respectively), whereas parasympathetic tone was reduced in malnourished compared with control rats (-4 ± 4 vs 22 ± 9 b.p.m., respectively). 5. The ratio of oscillations in HR induced by sympathetic and parasympathetic activity was higher in malnourished compared with control rats (0.43 ± 0.03 vs 0.34 ± 0.02, respectively). 6. The results of the present study indicate that protein malnutrition after weaning increases sympathetic activity and reduces vagal activity to the heart in rats. These data provide a new perspective on the pathophysiology of metabolic and cardiovascular diseases associated with protein malnutrition, especially with regard to autonomic modulation.

MATERIALS
Product Number
Brand
Product Description

Methylatropine bromide, European Pharmacopoeia (EP) Reference Standard

Social Media

LinkedIn icon
Twitter icon
Facebook Icon
Instagram Icon

MilliporeSigma

Research. Development. Production.

We are a leading supplier to the global Life Science industry with solutions and services for research, biotechnology development and production, and pharmaceutical drug therapy development and production.

© 2021 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.

Reproduction of any materials from the site is strictly forbidden without permission.