Sympathetic Responses in Caloric Stimulation:Role in the Cardiovascular Control of Anesthetized Rats / 航天医学与医学工程

ABSTRACT

Objective To explore the potential connection between sympathetic response, heart rate and blood pressure modulation after caloric irrigation in order to study the role of vestibular stimuli in cardiovascular control. Method Efferent splanchnic nerve firing rates, ECG and blood pressure were recorded simultaneously during caloric stimuli on intact anesthetized(CON) rats(n=5), sinoaortic denervated (SAD)rats(n=5) and bilateral vestibular destroyed (VD) rats(n=5). Result It was found that after caloric stimulation with ice water mean blood pressure CON rats with intact reflex became lower and the mean heart rates became slower, splanchnic sympathetic nerve activities increased for a moment and then dropped significantly. SAD rats had significant stronger splanchnic sympathetic nerve activities VD rats after caloric stimulation, and their blood pressures changed to apposite directions. The coupled respiratory component on splanhnic sympathetic nerve activities were strongly affected by the caloric stimulation. Conclusion It is suggested that semicircular canal stimulation participate at least in the short-term blood pressure control mechanism and the role of central nervous system on respiratory drive may also be involved. Baro-reflex and vestibular afferent may play different role in the control of blood pressure they may work synergically in some physiological control processed.