Characterization of dopamine releasable and reserve pools in Drosophila larvae using ATP/P2X2‐mediated stimulation. (3rd June 2015)

• Record Type: Journal Article
• Authors: Xiao, Ning; Venton, B. Jill
• Is Part Of: Journal of neurochemistry. Volume 134:Number 3(2015:Aug.)
• Page Start: 445
• Page End: 454
• Publication Date: 2015-06-03
• Subjects: Neurochemistry -- Periodicals; 616.8042
• DOI: 10.1111/jnc.13148
• Languages: English
• ISSNs: 0022-3042

Abstract

<abstract abstract-type="main" id="jnc13148-abs-0001"> <title>Abstract</title> <p>Dopaminergic signaling pathways are conserved between mammals and <italic>Drosophila</italic>, but the factors important for maintaining the functional pool of synaptic dopamine are not fully understood in <italic>Drosophila</italic>. In this study, we characterized the releasable and reserve dopamine pools in <italic>Drosophila</italic> larvae using ATP/P2X<sub>2</sub>‐mediated stimulation. Dopamine release was stable with stimulations performed at least every 5 min but decayed with stimulations performed 2 min apart or less, indicating the replenishment of the releasable pool occurred on a time scale between 2 and 5 min. Dopamine synthesis or uptake was pharmacologically inhibited with 3‐iodotyrosine and cocaine, respectively, to evaluate their contributions to maintain the releasable dopamine pool. We found that both synthesis and uptake were needed to maintain the releasable dopamine pool, with synthesis playing a major part in long‐term replenishment and uptake being more important for short‐term replenishment. These effects of synthesis and uptake on different time scales <italic>in Drosophila</italic> are analogous to mammals. However, unlike in mammals, cocaine did not activate a reserve pool of dopamine in <italic>Drosophila</italic> when using P2X<sub>2</sub> stimulations. Our study shows that both synthesis and uptake replenish the releasable pool, providing a better understanding of dopamine regulation in <italic>Drosophila</italic>. <graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgj1m9dzkv0" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></p> <p>The maintenance of the releasable dopamine pool was examined in <italic>Drosophila</italic> larva. Both synthesis and uptake were needed to maintain the releasable dopamine pool, with synthesis being most important on a longer time scale and uptake on a shorter time scale. Dopamine release was stimulated by applying ATP which activated P2X<sub>2</sub> channels specifically expressed in dopaminergic neurons.</p> </abstract>