Postnatal development of the adrenergic nerve connections and catecholamine-containing cells of the rat carotid body

Summary

The adrenergic nerve connections and the catecholamine-containing cells of the carotid body in postnatal rats of different ages were studied using the formaldehydeinduced fluorescence (FIF) method. The main findings are summarized as follows: 1) An intensely fluorescent nerve trunk was seen to reach the carotid body, 2) a specific adrenergic periglandular nerve plexus was formed around the carotid body, 3) a distinct decrease of the fluorescence intensity was observed in the carotid body during the first two postnatal weeks, 4) aberrant cells or cell cords, showing the same fluorescence characteristics as those in the carotid body, were often seen beside or inside the fluorescent nerve trunks emerging from the superior cervical ganglion, 5) the carotid body fluorescent cells often seemed to send processes, which were hard to separate from the varicose parenchymal adrenergic nerves in the carotid body.

A functionally active adrenergic sympathetic innervation of the carotid body during the postnatal period is suggested. Correlations with the physiological observations are discussed.