Modulation of allostatic load by fluoxetine and ascorbic acid in stressed Drosophila melanogaster

Abstrakt

Allostatic load from unabated stress condition may manifest in prolong irritation, physical exhaustion, memory loss, depressive-like behaviours and apoptosis. We investigate the role of fluoxetine and ascorbic acid to lower the threshold for allostatic load and reverse the effects of stressful experience. Wild –type strain of Drosophila melanogaster (w1118), in three experimental groups were treated for 24h, 96h and 168h with fluoxetine (FT), ascorbic acid (AAT) and fluoxetine plus ascorbic acid (FAAT) before exposure to heat stress at 37oC. The exhaustion times- Te and recovery times- Trc were recorded. Motor and memory performance were assessed using climbing and cognition assays, and effects of the prolonged exposure to drug were monitored. The kinetics of disposition of the allostatic load effects in the flies were also determined. The Te were significantly longer (P= 0.0003) and Tr significantly shorter (P= 0.00019) respectively in FT, AAT and FAAT groups than the control at 24h and 96h but not at 168h. The Performance Index (PI) of motor activity were significantly higher for the FAAT group (P= 0.03) compared to the FT and AAT after recovery from exhaustion. The area under the concentration-time curve (AUCal-effect) was significantly lower and the clearance, CL al-effects, significantly higher with FAAT group. Learning Index (LI) in all treatment groups were higher compared to the untreated flies (P= 0.0006). Conclusively, fluoxetine, ascorbic acid and fluoxetine–ascorbic acid combination have potential to delay consequential effects of allostatic load and enhance clearance of stress effects, recovery and memory retrieval capacity in Drosophila. This may have implication in human stress management.