OBTENTION OF NATURAL MEMBRANES ENRICHED WITH GABAA RECEPTOR FROM DISEASE VECTOR INSECTS ( Aedes aegypti and Triatoma infestans )

IVAN FELSZTYNA; NICOLAS G COLMANO; ANAHI V. TURINA; MARIELA E. SÁNCHEZ; VIRGINIA MIGUEL; DANIEL A. GARCÍA

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

The nervous system of insects is the main target of the most used insecticides. The most important neuronal targets include acetylcholinesterase inhibitors, nicotinic acetylcholine receptor agonists, voltage-activated sodium channel modulators, GABAA receptor antagonists and glutamate inhibitory receptor blockers. γ-aminobuyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system (CNS). Its specific receptor, the GABAA receptor (GABAA-R), is constituted by five subunits which compose a chloride channel. The most common subunit combination in mammals? brain is 2α2β1γ, even though there exists a wide diversity in subunit composition. In insects, the diversity of subunits is considerably minor, being the so-called RDL (resistant to dieldrin) the most representative subunit. Considering that the receptor subunit composition is critical for the pharmacological and biophysical properties of GABAA-Rs, functional and structural differences between receptors from mammals and insects provide multiple opportunities for designing more selective and non-toxic insecticides.The aim of this work was to obtain GABAA enriched natural membranes from the nervous system of Aedes aegypti and Triatoma infestans. For this purpose, the membranes were extracted from the head-thorax portion of A. aegypti larvae (IV instar) or T. infestans nymphs (V instar), by differential centrifugation procedures. The protein composition of the different fractions obtained in the centrifugation protocol was visualized by SDS-PAGE. The presence of GABAA-Rs in the membrane samples was determined by using [3H]-Flunitrazepam ([3H]-FNZ), a ligand that specifically binds to the benzodiazepine site of GABAA receptors.