Morphological evidence for a direct innervation of the mouse vomeronasal glands

The morphological evidence for a direct autonomic innervation of the mouse vomeronasal glands is presented. Axonal varicosities containing a few dense-core vesicles and numerous clear vesicles (36-60 nm in diameter) make synaptic contacts with the secretory cells at the base of the glandular acini. The axonal presynaptic membrane is associated with a distinct dense material and it is separated from the secretory cell by a synaptic cleft of about 12-14 nm. At the postsynaptical level, coated vesicles can be found. Additional postsynaptical specializations have not been observed.