Rodent behavioural test - Anxiety - Light Dark - NEUROFIT Preclinical Contract Research Organization (CRO) for CNS and PNS disorders

Light Dark test in mice

reliable anxiety screening test

Presentation

The light dark (LD) test is used to evaluate the relative anxiety status of mice.

The light dark paradigm in mice is based on a conflict between the innate aversion to brightly illuminated areas and the spontaneous exploratory activity. If given a choice between a large brightly compartment versus a small dark compartment, mice spontaneously prefer the dark. Anxiolytic compounds have been found to increase the total duration of time spent there. Anxiogenic compounds are observed to work in the opposite way.

Compound testing

Compound testing addresses the effect of acute treatment on the total duration of time spent in the lit box. Investigation of the effect of subchronic treatment is also possible.
Endpoints

Time spent in the lit box (s)

Dose-response curve of diazepam-treated mice
in the Light-Dark test.
Diazepam produces a dose-dependent reduction of time spent in the lit box, suggesting an anxiolytic effect.

Diazepam ≥ 2 mg/kg is associated with reduced locomotion in the OF
which suggests a sedative effect at doses higher than 2 mg/kg.

Injection of CCK-4 (cholecystokinin tetrapeptide) enhances the anxiety status of mice. The panic effect of CCK-4 is suppressed by Diazepam treatment.

Light-Dark test in mice is a well accepted model for screening anxiolytic compounds. However, not many CROs offer to conduct this test due to the fact that its sensitivity is highly dependent on the baseline level of the control animals, which is in turn dependent upon careful management of the environmental testing conditions. Neurofit has offered the Light-Dark test in mice for more than 15 years and produced consistent data throughout this time. It has been implemented not only for drug screening but also for phenotyping purposes.

Moreover, Neurofit also offers a variant of the Light-Dark test in order to mimic the CCK-4 - induced panic anxiety as modelled in human healthy volunteers.