CARDIAC EFFECTS OF NICOTINE EXPOSURE IN DROSOPHILA MELANOGASTER ARE MEDIATED BY SUBUNITS ALPHA1 AND 7 OF THE NICOTINE RECEPTOR

SANTALLA MANUELA; BALCAZAR DARIO; GOMEZ IVANA; FERRERO PAOLA; PAGOLA LUCIA; VALVERDE CARLOS A

Online

Congreso; REUNIÓN DE SOCIEDADES DE BIOCIENCIAS 2020; 2020

The relationship between substances consumed by humans andtheir impact on health has been explored in different animal modelsin an attempt to deepen on mechanisms of absorption, distribution,metabolization, and effects exerted in the organism. Drosophilamelanogaster has been widely used as a model to study the pathophysiology induced by several substances, e.g. nicotine. This workaims to provide information about the effects of this componentof tobacco in the heart. We explored the genetic relevance of thetwo subunits (α1 and α7) of the nicotine receptors in the cardiacresponse of Drosophila melanogaster exposed to nicotine. We evaluated intracellular calcium handling, the phenomenon underlying ofheart performance, by means of a cardiac targeted genetically-encoded reporter system, TinC-Gal4-UAS-GCaMP3. Seven-days-oldadult flies expressing a siRNA targeted to the α1/7 subunits of thenicotine receptor were compared to wild-type individuals to evaluate the impact of subunits downregulation. A pulse of nicotine wasspiked to the semi-intact preparation of the heart (1.69 mM, finalconcentration) to exert acute effects on heart activity.The addition of nicotine incremented the heart rate (89.14±9.36vs 107.86±11.18 beats/min n=9-10) and accelerated the maximalvelocities of contraction and relaxation (dΔF/dtmax: 0.164±0.02 vs0.213±0.02; -dΔF/dtmax: -0.118±0.015 vs -0.181±0.015 n=9-10)and relaxation time in wild-type flies (0.187±0.025 vs 0.12±0.004n=8). These effects were abolished when α1/7 subunits of the nicotine receptor were downregulated. Paired Student´s t-test was usedfor statistical analysis, where p values