Classical analgesic drugs modulate nociceptive-like escape behavior in Drosophila melanogaster larvae

• Published in: Research results in pharmacology (English ed.) Vol. 8; no. 4; pp. 185 - 196
• Main Authors: Santos-Silva, Thamyris, Lopes, Caio Fábio Baeta, Gumarães, Jennifer Diniz Soares, Valer, Felipe Berti, Kuhn, Gustavo Campos Silva, Romero, Thiago Roberto Lima, Naves, Lígia Araújo, Duarte, Igor Dimitri Gama
• Format: Journal Article
• Language: English
• Published: Belgorod National Research University 22-12-2022
• ISSN: 2658-381X; 2658-381X
• DOI: 10.3897/rrpharmacology.8.91390

Introduction: Nociceptive stimulus triggers escape responses in Drosophila melanogaster larvae, characterized by 360° rolling behavior along its own body axis. Therefore, it is possible to study analgesic drugs based on this stereo­typical nociceptive-like escape behavior. Here, we aimed to develop an analgesic predictive validity test of thermal nociception through D. melanogaster larvae.
Materials and methods: We evaluated the effect of classical analgesics (morphine, dipyrone, acetylsalicylic acid (ASA) and dexamethasone (DXM)) in the rolling behavior latency of D. melanogaster larvae exposed to thermal-acute noxious stimulus and nociceptive sensitization paradigm. Drugs were injected into hemocoel (100 nL) before nocicep­tive measurement.
Results and discussion: Rolling behavior latency was increased by morphine (2, 4, 8 and 16 ng) in dose-dependent manner. Naloxone (4 ng) fully reversed maximum effect of morphine. Dipyrone (32, 64 and 128 ng) and DXM (8 and 16 ng) elicited dose-dependent antinociceptive effects. Exposure of larvae to 97% of maximal infrared intensity induced nociceptive sensitization, i.e., latency changed from 12 to 7.5 seconds. ASA (25, 50 and 100 ng) and DXM (4, 8 and 16 ng) were administered 150 min after nociceptive sensitization and displayed reverse sensitization in rapid onset (30 min after injection). DXM (16 ng), injected prior to nociceptive sensitization, displayed a delay in the onset of action (150 min after injection). Locomotor behaviors were not affected by analgesic substances.
Conclusion: Our findings open perspectives for evaluation and discovery of antinociceptive drugs using D. melano­gaster larvae model.
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