The influence of long term voluntary exercise on cardiac autonomic function in conscious chronic kidney disease animals

Divya S. Kandukuri, Cara M. Hildreth, Ann K. Goodchild, Eugene Nalivaiko, Jacqueline K. Phillips

Research output: Contribution to journalMeeting abstractpeer-review

Abstract

Background: Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular morbidity and mortality. Exercise has enduring cardio-protective effects that arise, in part, as a result of improved autonomic control of heart rate (HR). The aim of our study was to determine if voluntary exercise improves autonomic function in conscious animals with CKD, specifically examining the balance between sympathetic and parasympathetic cardiac tone. Methods: Mixed sex Lewis and Lewis polycystic kidney disease (LPK) rats were used. Animals were divided into four groups: sedentary Lewis (SL) (n=4); exercise Lewis (EL) (n=3); sedentary LPK (SLPK) (n=2); and exercise LPK (ELPK) (n=2). The exercise group was provided unlimited access to an activity wheel in their home cage from 5 weeks of age, and the sedentary group a locked activity wheel. At 10 weeks of age, rats were implanted with radio-telemetry probes. At 13 weeks, resting HR, mean blood pressure (MBP) and activity were determined over a 20 minute period during the day and changes in HR in response to atenolol (AT, 1 mg/kg i.p.) and methylatropine (MA, 2 mg/kg, i.p.). Results: Resting HR and activity was not significantly different between any groups. MBP was higher in both ELPK and SLPK compared with Lewis (average: 213.4 ± 3.8 vs. 96.8 ± 2.8 mmHg, P<0.05). In the ELPK compared to SLPK, atenolol produced a smaller reduction in HR (-47.5 ± 0.8 vs. -66.9 ± 2.8 bpm, P<0.05) and methylatropine a greater increase in HR (85.8 ± 5.3 vs. 54.9 ± 5.1 bpm, P<0.05) indicating a relative reduction in sympathetic and increase in vagal tone in the exercised animals. This was not observed in the Lewis rats. Conclusion: Our preliminary data demonstrates that exercise promotes vagal control of HR in rodents with CKD. Future studies will identify if this translates to an improvement in baroreflex control of HR.
Original languageEnglish
Article numberA497
Number of pages1
JournalHypertension
Volume62
Issue numberSupplement 1
Publication statusPublished - Sep 2013
EventAmerican-Heart-Association High Blood Pressure Research Scientific Sessions - New Orleans, Lao People's Democratic Republic
Duration: 11 Sep 201314 Sep 2013

Keywords

  • voluntary exercise
  • cardiac autonomic function
  • chronic kidney disease

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