Contribution of the cervical sympathetic ganglia to the innervation of thepharyngeal arch arteries and the heart in the chick embryo

In the chick heart, sympathetic innervation is derived from the sympathetic neural crest (trunk neural crest arising from somite level 10-20). Since t he trunk neural crest gives rise to sympathetic ganglia of their correspond ing level, it suggests that the sympathetic neural crest develops into cerv ical ganglia P14. We therefore tested the hypothesis that, in addition to t he first thoracic ganglia, the cervical ganglia might contribute to cardiac innervation as well. Putative sympathetic nerve connections between the cervical ganglia and the heart were demonstrated using the differentiation markers tyrosine hydroxy lase and HNK-1. In addition, heterospecific transplantation (quail to chick ) of the cardiac and trunk neural crest was used to study the relation betw een the sympathetic neural crest and the cervical ganglia. Quail cells were visualized using the quail nuclear antibody QCPN. The results by immunohistochemical study show that the superior and the mid dle cervical ganglia and possibly the carotid paraganglia contribute to the carotid nerve. This nerve subsequently joins the nodose ganglion of the va gal nerve via which it contributes to nerve fibers in cardiac vagal branche s entering the arterial and venous pole of the heart. In addition, the caro tid nerve contributes to nerve fibers connected to putative baro- and chemo receptors in and near the wall of pharyngeal arch arteries suggesting a rol e of the superior and middle cervical ganglia and the paraganglia of the ca rotid plexus in sensory afferent innervation. The lower cervical ganglia 13 and 14 contribute predominantly to nerve branches entering the venous pole via the anterior cardinal veins. We did not observe a thoracic contributio n. Heterospecific transplantation shows that the cervical ganglia P14 as we ll as the carotid paraganglia are derived from the sympathetic neural crest . The cardiac neural crest does not contribute to the neurons of the cervic al ganglia. We conclude that the cervical ganglia contribute to cardiac inn ervation which explains the contribution of the sympathetic neural crest to the innervation of the chick heart. Anat Rec 255:407-419, 1999. (C) 1999 W iley-Liss, Inc.