The actions of the neonicotinoid imidacloprid on cholinergic neurons of Drosophila melanogaster

• Published in: Invertebrate neuroscience Vol. 6; no. 1; pp. 33 - 40
• Main Authors: Jepson, James E C, Brown, Laurence A, Sattelle, David B
• Format: Journal Article
• Language: English
• Published: Germany Springer Nature B.V 01.03.2006
• Subjects: Acetylcholine - metabolism; Animals; Animals, Genetically Modified; Calcium Channels - drug effects; Calcium Channels - metabolism; Cells, Cultured; Drosophila melanogaster; Fura-2; Imidazoles - pharmacology; Insecticides - pharmacology; Microscopy, Fluorescence; Neonicotinoids; Neurons; Neurons - drug effects; Neurons - metabolism; Nicotine; Nitro Compounds; Receptors, Nicotinic - drug effects; Receptors, Nicotinic - metabolism
• ISSN: 1354-2516; 1439-1104
• DOI: 10.1007/s10158-005-0013-8

The neonicotinoid insecticide imidacloprid is an agonist on insect nicotinic acetylcholine receptors (nAChRs). We utilised fura-2-based calcium imaging to investigate the actions of imidacloprid on cultured GFP-tagged cholinergic neurons from the third instar larvae of the genetic model organism Drosophila melanogaster. We demonstrate dose-dependent increases in intracellular calcium ([Ca2+]i) in cholinergic neurons upon application of imidacloprid (10 nM-100 muM) that are blocked by nAChR antagonists mecamylamine (10 microM) and alpha-bungarotoxin (alpha-BTX, 1 microM). When compared to other (untagged) neurons, cholinergic neurons respond to lower concentrations of imidacloprid (10-100 nM) and exhibit larger amplitude responses to higher (1-100 microM) concentrations of imidacloprid. Although imidacloprid acts via nAChRs, increases in [Ca2+]i also involve voltage-gated calcium channels (VGCCs) in both groups of neurons. Thus, we demonstrate that cholinergic neurons express nAChRs that are highly sensitive to imidacloprid, and demonstrate a role for VGCCs in amplifying imidacloprid-induced increases in [Ca2+]i.