Anopheles gambiae mosquito isolated neurons: a new biological model for optimizing insecticide/repellent efficacy

To understand better the mode of action of insecticides and repellents used in vector-borne diseases control, we developed a new biological model based on mosquito neurons isolated from adults Anopheles gambiae heads. This cellular model is well adapted to multidisciplinary approaches: electrophysiology, pharmacology, molecular biology and biochemical assays. Using RT-PCR, we demonstrated that isolated neurons express the nicotinic acetylcholine receptor subunit α1 (Agα1 nAchR), two acetylcholinesterases (AChE-1 and AChE-2) and three voltage-gated ion channels required for membrane excitability (AgCav1, AgNav1 and AgKv1). In order to correlate the expression of the different transcripts, encoding functional AgNav channel, nAChR receptor and AChE enzymes detected by RT-PCR, with electrophysiological activity we used patch-clamp technique. We revealed that AgNav and AChE which are targeted by insecticide and/or repellent were sensitive to the pyrethroid permethrin and to the repellent DEET, respectively. In addition, using colorimetric method, we also showed that AChE was sensitive to the carbamate propoxur. These results indicated that this novel neuronal mosquito model will lead to molecular and functional characterization of insecticide/repellent targets and appears as a powerful tool to investigate the development of highly specific and effective strategies for disease vector control.