The typological features of heart rate variability changes in inbred rats at peripheral α1-adrenoreceptors stimulation
The changes of heart rate variability (HRV) of inbred rats at a single introduction of α1-adrenomimetic phenylephrine (PE – 0.5 mg/kg body weight) and at a seven-day introduction of PE (0.3 mg/kg body weight) with consideration for the initial condition of individuals regulatory systems, that was defined at the absolute capacity of HF waves dominating in the spectrum, were studied. It is established that rats having the average HF-waves capacity (type vegetative balance) demonstrate the fastest and significant decrease of heart frequency, as well as the significant increase of RR-intervals variability in the HF range at a single introduction of PE, in all ranges, especially in VLF and LF at a seven-day introduction of PE. Individuals with high waves HF capacity (vagotonic type) have the similar changes of HVR, but these changes develop more slowly and at a seven-day introduction of PE differ by an especially strong growth of VLF waves capacity. Rats with low HF waves capacity (sympathetic type) have the weakest bradycardia as well as both the slow HF-, LF-, VLF-waves amplification and the increase of index centralization at a single introduction of PE. At a seven-day introduction of PE in these rats only HF waves show a moderate increase of capacity, it proves that the activity of the independent contour of regulation remains predominant. Thus, the stimulation of peripheral a1-adrenoreceptors can be accompanied by the growth of the capacity of all waves of spectrum HVR, and not only LF waves. Hence, it is capable to induce the increase of depressor mechanisms activity with participation of all levels of the regulation system. Accordingly, for revealing natural reactions to pharmacological tests it is necessary to take into account the initial type HRV of experimental animals.
About Authors (Correspondence):
Kuriyanova E.V. – candidate biological sciences, assistant professor of the chair for physiology and morphology of human and animals, e-mail: firstname.lastname@example.org
Sitimov A.M. – magistrand on «Natural scientific education» of biological faculty
Horst N.А. – doctor of biological sciences, professor of the chair for physiology and morphology of human and animals
Teply D.L. – doctor of biological sciences, professor, head of the chair for physiology and morphology of human and animals