Immunocytochemical demonstration of ك1-subunit of Na+/K+-ATPase in the mechanoreceptive Ruffini-like endings of the rat incisor ligament

The localization of one of the isoforms of Na+/K+-ATPase, the ك1-subunit, was investigated in the periodontal Ruffini endings of rat incisors by light- and electron-microscopic immunocytochemistry. Immunoreactivity for the rat ك1-subunit followed the pattern of dendritic terminal arborization in the alveolar half of the lingual periodontal ligament. Ultrastructurally, the reaction products were localized in dilatations of axons, possibly the terminals of Ruffini-like endings in the periodontal ligament. No immunoreactivity was seen in Schwann cells. The immunostaining results support the view that the ك1-subunit of Na+/K+-ATPase is the predominant isoform in sensory neurones, and that this protein is a useful marker for periodontal Ruffini-like endings.