Measuring sociability of mice using a novel three-chamber apparatus and algorithm of the LABORAS™ system

BACKGROUND

The social approach and social novelty tests utilizing the three-chamber apparatus are widely accepted to measure social behavior of rodents. The LABORAS™ system offers a possibility to assess sociability of mice in a reliable and objective manner.

NEW METHOD

We assessed the capability of the LABORAS™ sociability cage and algorithm (2.6.6) to detect social behaviors in mice. Furthermore, we investigated whether the system is able to detect various levels of sociability due to genetic background or after pharmacological treatments.

RESULTS

By comparing manual scoring with various detection zone settings of the automated registration, the most fitting algorithm with a detection zone radius of 90 mm was identified. When different strains were investigated, C57Bl/6 J and NMRI mice proved to be social, while CD1 mice were found asocial. The system was able to detect the sociability increasing effect of R-baclofen (0.5 mg/kg i.p.) and oxytocin (12 ng i.c.v.) in asocial CD1 mice. The negative control PCP impaired social behavior of C57Bl/6 J mice (1 mg/kg i.p.) and increased social avoidance in CD1 mice (0.3 mg/kg i.p.).

COMPARISON WITH EXISTING METHOD(S)

This setup, in contrast to video frame analysis softwares, determines signal changes caused by movements of rodents allowing accurate detection and analysis of trajectories. Parallel automated measurements also allow replacing time and labor intensive, highly subjective human observational work.

CONCLUSIONS

The set-up provides a fast and reliable method to examine social behavior of mice in the three-chamber apparatus. The system is capable of detecting pro or antisocial activity of pharmacological agents.

Utility of different outcome measures for the nitroglycerin model of migraine in mice

INTRODUCTION

Majority of the work for establishing nitroglycerin (NTG)-induced migraine models in animals was done in rats, though recently some studies in mice were also reported. Different special formulations of NTG were investigated in various studies; however, NTG treated groups were often compared to simple saline treated control groups. The aim of the present studies was to critically assess the utility of a panel of potential outcome measures in mice by revisiting previous findings and investigating endpoints that have not been tested in mice yet.

METHODS

We investigated two NTG formulations, Nitrolingual and Nitro Pohl, at an intraperitoneal dose of 10mg/kg, in comparison with relevant vehicle controls, and evaluated the following outcome measures: light aversive behaviour, cranial blood perfusion by laser Doppler imaging, number of c-Fos- and neuronal nitrogen monoxide synthase (nNOS)-immunoreactive neurons in the trigeminal nucleus caudalis (TNC) and trigeminal ganglia, thermal hyperalgesia and tactile allodynia of the hind paw and orofacial pain hypersensitivity.

RESULTS

We could not confirm previous reports of significant NTG-induced changes in light aversion and cranial blood perfusion of mice but we observed considerable effects elicited by the vehicle of Nitrolingual. In contrast, the vehicle of Nitro Pohl was apparently inert. Increased c-Fos expression in the TNC, thermal hyperalgesia, tactile allodynia and orofacial hypersensitivity were apparently good endpoints in mice that were increased by NTG-administration. The NTG-induced increase in c-Fos expression was prevented by topiramate but not by sumatriptan treatment. However, the NTG-induced orofacial hypersensitivity was dose dependently attenuated by sumatriptan.

DISCUSSION

Our results pointed to utilisable NTG formulations and outcome measures for NTG-induced migraine models in mice. Pending further cross-validation with positive and negative control drugs in these mouse models and in the human NTG models of migraine, these tests might be valuable translational research tools for development of new anti-migraine drugs.