Treatment with pentylenetetrazole (PTZ) and 4-aminopyridine (4-AP) differently affects survival, locomotor activity, and biochemical markers in Drosophila melanogaster

Abstract

PTZ is a convulsive agent that acts via selective blockage of GABA_A receptor channels, whereas 4-AP leads to a convulsive episode via blockage of K⁺ channels. However, the mechanism(s) by which pentylenetetrazole (PTZ) and 4-aminopyridine (4-AP) cause toxicity to Drosophila melanogaster needs to be properly explored, once it will help in establishing an alternative model for development of proper therapeutic strategies and also to counteract the changes associated with exposure to both epileptic drugs. For the purpose, we investigated the effects of exposure (48 h) to PTZ (60 mM) and/or 4-AP (20 mM) on survival, locomotor performance, and biochemical markers in the body and/or head of flies. 4-AP-fed flies presented a higher incidence of mortality and a worse performance in the open field test as compared to non-treated flies. 4-AP also caused a significant increase in the reactive species (RS) and protein carbonyl (PC) content in the body and head. Also a significant increase in catalase and acetylcholinesterase (AChE) activities was observed in the body. In the same vein, PTZ exposure resulted in a significant increase in RS, thiobarbituric acid reactive substances (TBARS), PC content, and catalase activity in the body. PTZ exposure also caused a significant increase in AChE activity both in body and head. It is important to note that PTZ-treated flies also down-regulated the NRF₂ expression. Moreover, both 4AP- and PTZ-fed flies presented a significant decrease in MTT reduction, down-regulation, and inhibition of SOD in body. However, SOD was significantly more active in the head of both 4-AP and PTZ-treated flies. Our findings provide evidence regarding the toxicological potential of both PTZ and/or 4-AP to flies. This model will help in decoding the underlying toxicological mechanisms of the stated drugs. It will also help to properly investigate the therapeutic strategies and to counteract the drastic changes associated with both epileptogenic drugs.

Keywords: Enzyme activity; Epileptogenic drugs; Gene expression; Oxidative stress.