Total number of synaptic vesicles [SVs] at an abdominal longitudinal muscle, 6, in 3rd instar larvae

Range ∼84,000 vesicles
Organism Fruit fly Drosophila melanogaster
Reference Kuromi, H., & Kidokoro, Y. (2003). Two synaptic vesicle pools, vesicle recruitment and replenishment of pools at the Drosophila neuromuscular junction. Journal of neurocytology, 32(5-8), 551-565. p.558 right column top paragraphPubMed ID15034253
Method P.558 left column 4th paragraph: "Sizes of SV pools: Because of continuing recycling of SVs, it is difficult to measure the absolute size of pools. To circumvent this problem [investigators] used shibire, which is defective in endocytosis at non-permissive temperatures but behaves normally at room temperature (Poodry & Edgar, 1979 Kosaka & Ikeda, 1983 Koenig et al., 1983, 1989, 1993). This mutant is suited for determination of sizes of SV pools. After tetanic stimulation at non-permissive temperatures, the presynaptic terminal can be completely depleted of SVs (Estes et al., 1996). Using this mutant a total number of SVs was measured by repetitively stimulating the presynaptic nerve at non-permissive temperatures to a complete exhaustion while continuously recording synaptic currents (Delgado et al., 2000, Fig. 6). In wild-type, the amplitude of synaptic currents quickly declined first but remained at a reduced level as long as the stimulation continued (Fig. 6A left trace marked CS, expanded traces are shown in B). This is due to recycling of SVs."
Comments P.558 left column bottom paragraph: "On the other hand, in shibire at non-permissive temperatures, the amplitude continued to decline and finally no synaptic currents were evoked (Fig. 6A right traces, expanded traces are shown in B (traces in the right). After 350 s of tetanic stimulation no synaptic currents were observed (bottom trace with 5-fold higher amplification than other traces.) [Investigators] can estimate how many quanta are in each synaptic current (i.e., quantal content) and calculate the total number of quanta released before complete exhaustion. A total number of SVs thus determined was ∼84,000 at an abdominal longitudinal muscle, 6, in 3rd instar larvae."
Entered by Uri M
ID 112562