AXONAL BOUTONS

• Bulbus regions of the axon designate synaptic sites. The enlargement, called a bouton is the result of transmitter packaging into synaptic vesicles. In addition the region is marked by presynaptic specializations of the synaptic contact site where transmitter gets released onto receptors of target neurons. Boutons includes macromolecules that make the presynaptic membrane more prominent over bouton contact sites and serve as adhesive and presynatic transmitter release sites.