Dopamine (DA) signaling affects locomotion, feeding, learning, and memory in C. elegans. Various assays have been developed to study the proteins involved in these behaviors; however, these assays show behavioral output only when there is a drastic change in DA levels. We designed an assay capable of observing behavioral output even with only slight alterations in DA levels. To achieve this, we designed a behavioral paradigm where we combined C. elegans movement with ethanol (EtOH) administration. The behavioral response to alcohol/EtOH and susceptibility to alcohol-use disorders (AUDs) have been linked to DA. Our assay correlates an increase in DA levels due to EtOH and movement obstruction due to a dry surface to a circular sedative behavior, which we designated as EtOH-induced sedative (EIS) behavior. We successfully utilized this assay to assign physiological and behavioral functions to a DA autoreceptor, DOP-2.

Pentylenetetrazole (PTZ) is a GABA_A receptor antagonist and is used to monitor presynaptic defects in the release of the inhibitory neurotransmitter GABA. PTZ is a competitive inhibitor of GABA, and prevents binding of GABA on the GABA_A receptors present on the surface of muscle. In the absence of GABA binding, the excitatory to inhibitory signal ratio increases resulting in a convulsive phenotype. This assay provides a fast and reliable method to detect presynaptic defects in GABAergic synaptic transmission. The assay is based on correlating the extent of convulsions with the degree of presynaptic GABA release defects.