Morphine Antidependence of Erythroxylum cuneatum (Miq.) Kurz in Neurotransmission Processes In Vitro

Figure 7

Vesicle trafficking for neurotransmission from the fusion machinery in the presynaptic terminal. The synaptic vesicle containing neurotransmitter consists of a number of vesicular SNARE (v-SNARE) such as VAMP 2, synaptotagmin 1, synapsin, calmodulin kinase II (CaMKII), and myosin-V. The activity of releasing neurotransmitter occurs in the active zone where the synaptic vesicles are accumulated and high concentration of Ca²⁺ is compulsory. During tethering phase, the vesicle moves to acceptor compartment and tethers through the organisation of a GTP-bound Rab and the tethering factor. The vesicle docks or immobilises the plasma membrane through the v-SNARE and t-SNARE complex assembling into a four-helix bundle. The SNARE complex leads the fusion of the vesicle and releases of protein or neurotransmitter which required a higher concentration of Ca²⁺. The exocytosis and endocytosis processes are taking place where the neurotransmitters are released to the synaptic gap and the vesicle is recycled (review by [43]).