Key result
Cardiac sympathetic and vagal stimulation produces smaller chronotropic responses in puppies versus adult dogs.
Why the study?
The study aimed to quantify heart rate changes from cardiac sympathetic and vagal nerve stimulation and to assess sympathetic-vagal interactions and age-related differences in autonomic regulation.
How do the chronotropic responses to cardiac sympathetic and vagal nerve stimulation differ between adult dogs and puppies, and what is the extent of peripheral sympathetic-vagal interactions?
Population
Eleven adult dogs and four puppies
Comparison
Right-sided vs left-sided nerve stimulation; adult dogs vs puppies; varying background vagal activity levels
Design
Factorial experimental design in preclinical animal study
Authors
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Blunted puppy responses warrant caution extrapolating adult autonomic data to pediatrics; leaves open maturation timeline in humans.
How do the chronotropic responses to cardiac sympathetic and vagal nerve stimulation differ between adult dogs and puppies, and what is the extent of peripheral sympathetic-vagal interactions?
This preclinical study demonstrates that while autonomic regulation of heart rate is functionally incomplete in puppies compared to adult dogs, the mechanisms for sympathetic-vagal interactions are fully developed early in life.
Mace et al. (1983) studied Autonomic nervous control of heart rate (n=15). Stimulation of the cardiac sympathetic and vagal nerves vs. Adult dogs vs puppies / left vs right-sided stimulation was evaluated on Changes in heart rate (chronotropic responses). Stimulation of cardiac sympathetic and vagal nerves produced significantly smaller chronotropic responses in puppies than in adult dogs, with prominent sympathetic-vagal interactions in both groups.
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