A sympathetic reflex elicited by experimental coronary occlusion.

MALLIANI, ALBERTO, PETER J. SCHWARTZ, and ALBERTO ZANCHETTI. A sympathetic rejex elicited by experimental coronary occlusion. Am. J. Physiol. 217(3): 703-709. 1969.-The effects of transient coronary occlusion on a sympathetic outflow presumably directed to the heart have been studied on cats. Single preganglionic fibers and a few multifiber strands have been isolated from the left third thoracic ramus communicans (Ts). Coronary occlusion quickly induced an increased discharge of most of the fibers tested. A very few fibers decreased their discharge, whereas some were apparently unaffected by coronary occlusion. Increased firing neither depended on direct anoxic stimulation of preganglionic neurons nor on sinoaortic or vagal reflexes and was observed in spinal preparations. A sympathetic cardio-cardiac reflex is proposed, the afferent and efferent pathways of which are both in sympathetic nerves.