Antagonistic and Synergistic Activation of Cardiovascular Vagal and Sympathetic Motor Outflows in Trigeminal Reflexes

BUCHHOLZ B; MÉNDEZ DIODATI N; BERNATENÉ E; BERNATENÉ E; KELLY J; GELPI RJ; KELLY J; GELPI RJ; BUCHHOLZ B; MÉNDEZ DIODATI N

The Trigemino-Cardiac Reflex: Beyond the Diving Reflex

Frontiers Media

Año: 2018; p. 28 - 33

The trigeminal nerve and heart are strongly relatedthrough somato-autonomic nervous reflexes that induce rapid changes incardiovascular function. Several trigeminal reflexes have been described, butthe diving and trigeminocardiac reflexes are the most studied. The heart is atarget organ dually innervated by the sympathetic and parasympathetic systems.Thus, how cardiac function is regulated during the trigeminal reflexes is theresult of the combination of an increased parasympathetic response and increased,decreased or unaltered sympathetic activity. Various hemodynamic changes occuras a consequence of these alterations in autonomic tone. Often in the oxygen-conservingphysiological reflexes such as the diving reflex, sympathetic/parasympatheticco-activation reduces the heart rate and either maintains or increases bloodpressure. Conversely, in the trigeminocardiac reflex, bradycardia andhypotension due to parasympathetic activation and sympathetic inactivation tendto be observed. These sudden cardiac innervation disturbances may promote thegeneration of arrhythmias or myocardial ischemia during surgeries in thetrigeminal territory. However, the function and mechanisms involved in thetrigeminal reflexes remain to be fully elucidated. The current review providesa brief update and analysis of the features of these reflexes, with specialfocus on how the autonomic nervous system interacts with cardiovascularfunction.