Fig. 1.6.39. Dense core vesicles (also called "dark center" or "large granulated vesicles" - arrows), here shown near mitochondria (m) in a myelinated axon (Ax) and in an astrocyte process (Ap), frequently appear also in axon terminals between synaptic vesicles. They are usually about 70-150 nm in diameter and resemble neurosecretory granules. Their function is not clear; neuropeptides are supposed. my - myelin, gf - gliofilaments. Scale = 150 nm. (Rat, thalamus and cerebellum.) Download the high resolution image (a); Download the high resolution image (b).