Honey intoxication and the Bezold-Jarisch reflex.

Food-poisonings with grayanotoxin-contaminated honey can induce atrioventricular blocks. Actually, grayanotoxin and similar neurotoxins like veratridine stimulate the unmyelinated afferent cardiac branches of the vagus nerve. Tonic inhibition of central vasomotor centres leads to a reduced sympathetic output and a reduced peripheral vascular resistance with bradycardia, continued hypotension, and peripheral vasodilation. This cardioinhibitory reflex is known as the Bezold-Jarisch reflex. Recognition of the Bezold-Jarisch reflex is important, as there is no need for electric pacing, when atrioventricular blocks occur. The pharmacologically induced bradycardia and heart blocks do promptly disappear after injection of the antidote atropine.