The genetic component of the forced diving bradycardia response in mammals.
We contrasted the forced diving bradycardia between two genetically similar (inbred) rat strains (Fischer and Buffalo), compared to that of outbred rats (Wistar). The animals were habituated to forced diving for 4 weeks. Each animal was then tested during one 40 s dive on each of 3 days. The heart rate (f(H)) was measured before, during, and after each dive. Fischer and Buffalo exhibited marked difference in dive bradycardia (Fischer: 120.9 ± 14.0 beats min(-1) vs. Buffalo: 92.8 ± 12.8 beats min(-1), P < 0.05). Outbred rats showed an intermediate response (103.0 ± 30.9 beats min(-1)) but their between-animal variability in mean dive f(H) and pre-diving resting f(H) were higher than the inbred strains (P < 0.05), which showed no difference (P > 0.05). The decreased variability in f(H) in inbred rats as compared with the outbred group indicates that reduced genetic variability minimizes variability of the diving bradycardia between individuals. Heritability within strains was assessed by the repeatability (R) index and was 0.93 ± 0.05 for the outbred, 0.84 ± 0.16 for Buffalo, and 0.80 ± 0.12 for Fischer rats for f(H) during diving. Our results suggest that a portion of the mammalian diving bradycardia may be a heritable trait.
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- 3208 Medical physiology
- 3101 Biochemistry and cell biology
- 1701 Psychology
- 1116 Medical Physiology
- 0606 Physiology
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Start / End Page
Related Subject Headings
- 3208 Medical physiology
- 3101 Biochemistry and cell biology
- 1701 Psychology
- 1116 Medical Physiology
- 0606 Physiology