Carotid sinus distension and superior cervical ganglion transmission.

The functional relationship between sinusal distension and the sympathetic innervation of the feline carotid sinus was investigated by neurophysiological techniques. A balloon catheter was used to distend the sinus region while recording evoked postganglionic activity from the superior cervical ganglion. When the SCG was stimulated at 1.0 or 10.0/s, balloon inflation reduced postganglionic action potential height by 25-50% and increased ganglionic negativity. These effects were subsequently abolished by section of one of the remaining intact postganglionic trunks. This evidence suggests that a pressure-modulated reflex arc, similar to the intestinointestinal reflex, might exist between the carotid sinus and superior and cervical ganglion.