Detection and Analysis of Synaptosis

Essentially three modes of synaptic elimination have been described (1 ): (1 ) loss of synapses in synaptically connected neurons following physiological neuron death during development or hormonally driven reorganization; (2 ) process (generally axonal) retraction and proteolytic degradation of presynaptic elements involving lysosomal upregulation and autophagy; (3 ) elimination of intact nerve terminals by glial phagocytosis (“synaptic stripping”), notably in the facial nucleus as a retrograde transneuronal effect following axotomy-here microglial cells play a major role (2 ,3 ). Similar phagocytosis of intact terminals can be performed by protoplasmic astrocytes as described below.