GLOMUS CELL-DIFFERENTIATION IN THE CAROTID-BODY REGION OF CHICK-EMBRYOS STUDIED BY NEURON-SPECIFIC CLASS-III BETA-TUBULIN ISOTYPE AND LEU-7MONOCLONAL-ANTIBODIES

Development of the carotid body and the glomus cell groups in the wall of the common carotid artery and its branches was examined in chicken s at various developmental stages by immunohistochemistry using three different monoclonal antibodies, i.e., anti-neuron-specific class III beta-tubulin isotype (TuJ1), anti-rat brain beta-tubulin, and anti-Leu -7 (HNK-1) antibodies. All the antibodies reacted with neurons. The ca rotid body anlage was first discerned at 6 days of incubation at the l ateral portion of the third branchial artery. The cells and nerve fibe rs immunoreactive for TuJ1, brain beta-tubulin and Leu-7, which were c onnected with the distal ganglion of the vagus nerve, were found aroun d the carotid body anlage at this stage. Within the carotid body anlag e, no immunoreactivity yet appeared. The immunoreactive cells were acc umulated around the carotid body anlage until 8 days of incubation. Fr om 9 days of incubation, the immunoreactive cells continuing with the distal vagal ganglion began to enter into the carotid body anlage and also dispersed widely along the common carotid artery and its branches , giving rise to the glomus cells. At 12 days of incubation, a large p ortion of the carotid body was occupied by the immunoreactive cells. T hus, the present study evidences that the glomus cells in the carotid body and around the arteries are emigres that arrive in each residenti al place from the distal vagal ganglion. Immunoreactivity for TuJ1, br ain p-tubulin, and Leu-7 in the glomus cells started to decrease at la te stages of embryonic development. After hatching, no TuJ1-immunoreac tive cells were detected in the carotid body region. (C) 1994 Wiley-Li ss, Inc.