Sympathetic Nervous Dysfunction in Diabetic Rats
Author Information
Author(s): Thackeray James T, Radziuk Jerry, Harper Mary-Ellen, Suuronen Erik J, Ascah Kathryn J, Beanlands Rob S, DaSilva Jean N
Primary Institution: University of Ottawa Heart Institute
Hypothesis
Sustained hyperglycemia in a rat model of insulin resistance would exhibit progressive sympathetic nervous dysfunction in parallel with deteriorating myocardial function.
Conclusion
Sustained hyperglycemia is associated with elevated myocardial norepinephrine content and dysregulation of sympathetic nervous system signaling without systolic impairment.
Supporting Evidence
- After 8 weeks of hyperglycemia, norepinephrine levels were significantly elevated in the hearts of diabetic rats.
- Diastolic function was impaired in hyperglycemic rats, indicated by prolonged mitral valve deceleration time.
- Sympathetic nerve density remained unchanged despite reduced norepinephrine transporter expression.
Takeaway
When rats have high blood sugar for a long time, their heart's nervous system doesn't work as well, even if the heart itself is still pumping normally.
Methodology
The study used a rat model to assess cardiac sympathetic nervous integrity through PET imaging and echocardiography, measuring norepinephrine levels and NET expression.
Limitations
The study could not determine the mechanistic cause of sympathetic nervous system defects and did not measure neurotrophins.
Participant Demographics
Adult male Sprague-Dawley rats, 200-250 g.
Statistical Information
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website