[Potentiation of the chronotropic reaction of the rabbit heart during nociceptive stimulation].
Experiments with tricuran curarized rabbits have demonstrated that biphasic response that occurs during nociceptive limb stimulation (10--20 V) resulted in a short-term unmarked increase in the hear rate (HR) followed by a prolonged decline of the HR and then transforms to remarkable potentiation of the bradycardiac component upon rhythmic stimulation. The maximal potentiation develops within 15--40 s at a frequency of 2--01 Hz. This demonstrates a non-liner correlation between the potentiation onset and the frequency increase within the ranges mentioned. After stimulation for 40--130 s there take place a noticeable decrease in the heart rate response and destruction of rhythmic reaction observed at a lower frequency, namely the response decline (habituation). At a lower frequency (less than 0.1 Hz) the potentiation develops within several minutes, reaches maximum in 150--250 s with the wave-like potentiation following. Thus, upon rare rhythmic nociceptive stimulation HR potentiation has an appreciable long-term effect when repeated many times, and affects the conditioning.
D000818:Animals; D001676:Biofeedback, Psychology / Q000502:physiology; D004558:Electric Stimulation; D006339:Heart Rate; D009619:Nociceptors / Q000502:physiology*; D011817:Rabbits; D013997:Time Factors
Potentsiatsiia khronotropnoĭ reaktsii serdtsa krolika pri notsitseptivnoĭ stimuliatsii.