Role of normal dendrites in removal of degenerating terminal boutons

The hypothesis is presented that degenerating boutons are partly removed by pinocytotic activity by dendrites, and it is suggested that histochemical investigations may give some clue to the understanding of their functional importance.

Abstract

In an electron microscopical study of terminal fiber and bouton degeneration in the inferior olive of the cat it was observed that multivesicular inclusion bodies occur in great number in normal dendrites adjacent to degenerating boutons. In addition pits are found on the surface of some dendrites which are in contact with degenerating boutons. The hypothesis is presented that degenerating boutons are partly removed by pinocytotic activity by dendrites. The role of the inclusion bodies in the process is not clear. They may be active in the further removal of the engulfed bouton material, and it is suggested that histochemical investigations may give some clue to the understanding of their functional importance. The degenerating boutons, in major part, probably are destroyed by autolytic processes.