Does respiratory sinus arrhythimia occur in fishes?
Research output: Contribution to journal › Article
The hypothesis that respiratory modulation of heart rate variability (HRV) or respiratory sinus arrhythmia (RSA) is restricted to mammals was tested on four Antarctic and four sub-Antarctic species of fish, that shared close genotypic or ecotypic similarities but, due to their different environmental temperatures, faced vastly different selection pressures related to oxygen supply. The intrinsic heart rate (f(H)) for all the fish species studied was similar to 25% greater than respiration rate (f(v)), but vagal activity successively delayed heart beats, producing a resting f(H) that was synchronized with fv in a progressive manner. Power spectral statistics showed that these episodes of relative bradycardia occurred in a cyclical manner every 2-4 heart beats in temperate species but at > 4 heart beats in Antarctic species, indicating a more relaxed selection pressure for cardio-respiratory coupling. This evidence that vagally mediated control of f(H) operates around the ventilatory cycle in fish demonstrates that influences similar to those controlling RSA in mammals operate in non-mammalian vertebrates.
|Number of pages||4|
|Publication status||Published - 22 Dec 2005|
- cardio-respiratory coupling, notothenioids, power spectral analysis, Antarctic fish