Composition Synaptic vesicle

primary hippocampal neurons observed @ 10 days in vitro confocal microscopy. in both images neurons stained somatodendritic marker, microtubule associated protein (red). in right image, synaptic vesicles stained in green (yellow green , red overlap). scale bar = 25 μm.

synaptic vesicles relatively simple because limited number of proteins fit sphere of 40 nm diameter. purified vesicles have protein:phospholipid ratio of 1:3 lipid composition of 40% phosphatidylcholine, 32% phosphatidylethanolamine, 12% phosphatidylserine, 5% phosphatidylinositol, , 10% cholesterol.

synaptic vesicles contain 2 classes of obligatory components: transport proteins involved in neurotransmitter uptake, , trafficking proteins participate in synaptic vesicle exocytosis, endocytosis, , recycling.

transport proteins composed of proton pumps generate electrochemical gradients, allow neurotransmitter uptake, , neurotransmitter transporters regulate actual uptake of neurotransmitters. necessary proton gradient created v-atpase, breaks down atp energy. vesicular transporters move neurotransmitters cells cytoplasm synaptic vesicles. vesicular glutamate transporters, example, sequester glutamate vesicles process.
trafficking proteins more complex. include intrinsic membrane proteins, peripherally bound proteins, , proteins such snares. these proteins not share characteristic make them identifiable synaptic vesicle proteins, , little known how these proteins deposited synaptic vesicles. many not of known synaptic vesicle proteins interact non-vesicular proteins , linked specific functions.

the stoichiometry movement of different neurotransmitters vesicle given in following table.

recently, has been discovered synaptic vesicles contain small rna molecules, including transfer rna fragments, y rna fragments , mirrnas. discovery believed have broad impact on studying chemical synapses.

effects of neurotoxins

some neurotoxins, such batrachotoxin, known destroy synaptic vesicles. tetanus toxin damages vesicle-associated membrane proteins (vamp), type of v-snare, while botulinum toxins damage t-snares , v-snares , inhibit synaptic transmission. spider toxin called alpha-latrotoxin binds neurexins, damaging vesicles , causing massive release of neurotransmitters.