The carotid sinus connections: a WGA-HRP study in the cat

The neural connections of the carotid sinus were studied by administration of horseradish peroxidase or a lectin conjugate to the adventitia of the carotid sinus of cats. The carotid sinus afferents project exclusively to the nucleus of the tractus solitarius (NTS). Rostral to the obex the projection is mainly ipsilateral with a strong contralateral component caudal to the obex. The carotid sinus projects to several NTS territories that do not receive afferents from the carotid body chemoreceptors; they are: the dorsolateral, the lateral extension of the commissural, the caudal intermediate, the ventrolateral and the gelatinosus subnuclei. In addition the carotid sinus central representation includes territories occupied also by carotid body terminals: dorsal, interstitial, rostral intermediate, medial and the medial part of commissural subnuclei (see previous paper). Labeled cell bodies were found in the petrosal (216 +/- 37, mean +/- S.E.M.) nodose (825 +/- 434) and superior cervical ganglia (3583 +/- 1227) demonstrating the sympathetic efferent innervation of the carotid sinus and a dual sensory innervation via both the glossopharyngeal and vagus nerves.