Methods for Studying the Mechanisms of Action of Antipsychotic Drugs in <em>Caenorhabditis elegans</em>

Abstract

Caenorhabditis elegans is a simple genetic organism amenable to large-scale forward and reverse genetic screens and chemical genetic screens. The C. elegans genome includes potential antipsychotic drug (APD) targets conserved in humans, including genes encoding proteins required for neurotransmitter synthesis and for synaptic structure and function. APD exposure produces developmental delay and/or lethality in nematodes in a concentration-dependent manner. These phenotypes are caused, in part, by APD-induced inhibition of pharyngeal pumping 1,2 . Thus, the developmental phenotype has a neuromuscular basis, making it useful for pharmacogenetic studies of neuroleptics. Here we demonstrate detailed procedures for testing APD effects on nematode development and pharyngeal pumping. For the developmental assay, synchronized embryos are placed on nematode growth medium (NGM) plates containing APDs, and the stages of developing animals are then scored daily. For the pharyngeal pumping rate assay, staged young adult animals are tested on NGM plates containing APDs. The number of pharyngeal pumps per unit time is recorded, and the pumping rate is calculated. These assays can be used for studying many other types of small molecules or even large molecules. Video LinkThe video component of this article can be found at

Towards High-Throughput Chemobehavioural Phenomics in Neuropsychiatric Drug Discovery

“…In the context of neurobiology C. elegans enables studies of neuronal development, connectivity, physiology, as well as alterations in behavioural traits, modulated by both genetic factors and pharmacological intervention [67,68,69,70,71,72]. Importantly, in contrast to zebrafish, it has a very well characterized nervous system with 302 neurons (divided into 118 distinct classes in addition to 56 glial cells), 1410 neuromuscular junctions, and 6393 chemical synapses (Avila et al, 2012) [67,71,73].…”

“…This organism is so far the only one of which we possess an entire neuronal wiring chart mapping all neurons and major synaptic connections [73,74]. Despite the sheer simplicity of nematode’s CNS, it exhibits a variety of interesting behaviours such as: different motion and gait patterns, electrotaxis, chemotaxis, thermotaxis, light avoidance, mechanotransduction, learning, memory, mating, and sleep-like behaviours [66,67,72,75]. These can be used to elucidate the functions of neuronal pathways.…”

“…These can be used to elucidate the functions of neuronal pathways. Recent reports suggests that C. elegans is an exceptional model to explore molecular foundations of addiction and other drug-induced behavioural effects [66,67,71,72,76]. The optical transparency of worms also provide ample opportunities to combine behavioural data with real-time visualization of neurons in a plethora of transgenic lines and even study neuronal excitability using live-animal calcium imaging [77].…”

Clozapine Modulates Glucosylceramide, Clears Aggregated Proteins, and Enhances ATG8/LC3 in Caenorhabditis elegans

“…The methods of the developmental assay have been detailed in (Hao and Buttner, 2014). Briefly, the well-grown adult animals were bleached using hypochlorite:1 N NaOH : ddH 2 O (1 : 4 : 5) to obtain synchronized eggs, 25 of which were then placed on the 12-well NGM assay plates containing variable concentrations of drugs.…”

Risperidone induced alterations in feeding and locomotion behavior of Caenorhabditis elegans

“…Altered neuronal development by APDs on axonal outgrowth & neuronal migration have been critically evaluated in C. elegans ( Donohoe et al, 2008 ) . Action mechanisms of APDs with clozapine for development and pharyngeal pumping alterations is another investigative study carried out in C. elegans ( Hao and Buttner, 2014 ).…”