RESUMEN
Large dense core vesicle in the trigeminal subnucleus caudalis of the rat has been observed electron microscopically. It is fixed in glutaraldehyde-osmium tetroxide following removal of the skin of the vibrissae areas. The findings of the present study are: 1.Morphological evidence for exocytosis of large dense core vesicle from non-synaptic sites of the axonal terminal has been presented.2. The large coated vesicles equipped with central densities derived from the invagination of the plasma membrane. These observations suggest that membrane recycling occur at location in the terminal via these coated vesicles.3.Some large dense core vesicles may also form the tubular structures which may represent smooth endoplasmic reticulum containing dense material. This study supports the hypothesis that release of the transmitter of the great dense core vesicles occur at nonsynaptic sites by exocytosis.