Comparative responses of acetylcholinesterase (AChE) of rat brain and model invertebrate Caenorhabditis elegans in vitro

This in vitro study was aimed to compare the kinetic properties of acetylcholinesterase (AChE) in two model systems i.e. rat brain homogenate and nematode model Caenorhabditis elegans. These models were analyzed with basic kinetic parameters viz., substrate hydrolysis, inhibition pattern, determined Km, V_max, IC₅₀, KI and V_imax using dichlorvos (DDVP), an organophosphorus compound widely used for insect-pest control in agricultural crops. The rat brain homogenate exhibited Km, Vmax and IC₅₀ values of 59 M, 33 nmol min⁻¹ mg⁻¹ protein and 107.18 ± 3.56 nM, respectively, for rat brain homogenate. C. elegans homogenate exhibited Km, Vmax and IC₅₀ values of 725.41 μM, 112.35 nmol min⁻¹ mg⁻¹ protein and 45.7 ± 2.68 nM, respectively. The pattern of inhibition was irreversible in both the systems. The study showed that C. elegans in vitro system can be used as a model to establish the inhibition pattern of organophosphorus compounds (known inhibitors of AChE) as compared to traditionally used rat brain homogenate system.