The effect of cervical vagotomy (decentralization) on the ultrastructure of the carotid body on the duck, Anas platyrhynchos.

Carotid bodies of ducks show no detectable changes in ultrastructure up to periods of four weeks following the removal of 2-3 cm of the cervical vagus (decentralization). This indicates that the majority, and possibily all the nerves terminating on the glomus cells are afferent (sensory) in nature. These nerve endings are in reciprocal synaptic contact with the glomus cells and therefore have efferent and afferent functions. Theories concerning the carotid body receptor mechanism are discussed with particular reference to those theories which ascribe functions to the reciprocal synapses.