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Grooming is a commonplace, robust behavior in rodent species. It has been shown to be highly sensitive to a number of experimental factors, making it an ideal target for manipulation. The complex patterning of grooming in rodents, which usually proceeds in a cephalo-caudal direction and involves several distinct stages, can be dissected into its constituent parts and microstructures. Several grooming patterning analysis methods are described in the protocol that allow for an assessment of this behavior based on measurements of grooming activity and its sequencing. Additionally, grooming can be evaluated in reference to the regional distribution and syntax in which it occurs. Owing to the ever-increasing number of rodent models that have strong grooming phenotypes, this high-throughput in-depth analysis is becoming crucial for biomedical research.

Abstract: In the present study, we suggest that long elevated horizontal rod (Suok test, ST) and its light–dark modification (LDST) may be used for behavioral characterization in mice, including simultaneous assessment of their anxiety, activity, and neurological phenotypes. To establish the ST and the LDST as murine models of anxiety, we used several different mouse strains which differ markedly in their anxiety and activity (C57BL/6, 129S1/SvImJ, NMRI, and BALB/c). Here we show that our tests are able to ethologically discriminate between high and low anxiety mouse strains, as assessed by horizontal and directed exploration, stops, and defecation boli. The spatial distribution of the LDST behaviors is also sensitive to these strain-specific anxiety phenotypes, showing clear avoidance of the brightly lit part of the test in stressed (rat exposed) vs. control NMRI mice. In addition, we validated the ST in 129S1/SvImJ and BALB/c mice by assessing the behavioral consequences of acute stress such as rat exposure. Finally, we showed that our test is able to detect high anxiety and poorer motor coordination in 129S1/SvImJ (vs. C57BL/6) mice. The results of our study show that the ST emerges as an experimental tool to analyze anxiety, motor-vestibular anomalies, as well as anxiety-induced motor impairments in mice. Overall, we suggest that the ST can be a useful protocol in neurobehavioral stress research including modeling stress-evoked states, pharmacological screening of potential anti-stress drugs, or behavioral phenotyping of genetically modified animals. [Copyright &y& Elsevier]

Abstract: Grooming is an important part of rodent behavioural repertoire, representing a complex hierarchically ordered cephalo-caudal sequence of patterns sensitive to stress and various drugs. Gamma-aminobutyric acid (GABA) is involved in the regulation of both anxiety and grooming behaviours. This study investigated the predictive validity of grooming behavioural microstructure as a marker of anxiety, by examining the effects of two GABAergic reference compounds, anxiolytic diazepam (0.1 and 0.5 mg/kg i.p.) and anxiogenic pentylenetetrazole (5 and 10 mg/kg i.p.) on mouse grooming. Our data suggest that the percentage of pattern transitions not fitting to the cephalo-caudal progression, and the percentage of interrupted grooming bouts are more reliable behavioural markers of stress bidirectionally sensitive to GABAergic anxiogenic and anxiolytic drugs, compared to the frequency and duration scores. Our study also confirms that detailed ethological analyses of grooming microstructure can be a useful tool in behavioural pharmacology of anxiety. [Copyright &y& Elsevier]

Since rodent self-grooming behaviours are elicited by both comfort and stressful conditions, traditional measures such as duration, latency of onset and the number of bouts may be not suitable to dissociate between these opposite conditions. The aim of the current study was to improve and optimize ethological measurement of self-grooming in neurobehavioural stress research enabling differentiation between stress and no-stress situations. This protocol assists in the correct interpretation of animal grooming behaviours and detection of stress by measuring alterations in grooming microstructure in different test situations. While a general pattern of self-grooming uninterrupted cephalocaudal progression is normally observed in no-stress (comfort) conditions in mice and other rodents, the percentage of “incorrect” transitions between different stages and the percentage of interrupted grooming bouts may be used as behavioural marker of stress. The protocol can be a useful tool in neurobehavioural stress research including modelling stress-evoked states, pharmacological screening of potential antistress drugs or behavioural phenotyping of genetically modified animals. [Copyright &y& Elsevier]

Abstract: Here, we study the role of a neurosteroid hormone Vitamin D in epilepsy. To examine this problem, we used 1,25-dihydroxyvitamin D, an active form of Vitamin D, injected subcutaneously to NMRI mice (33μg/20μl) 40min prior to seizures induced by systemic injection of pentylenenetrazole (PTZ, 70mg/kg). Overall, compared to the vehicle-treated control animals (n =11 in each group), the Vitamin D-treated mice demonstrated reduced severity of PTZ-induced seizures (longer latency, shorter duration and lower mortality). In a separate experiment, we assessed the time-course of antiepileptic effects of 1,25-dihydroxyvitamin D. For this, we injected this compound (33μg/20μl) to NMRIx129S1 mice (n =11) 40min, 3, 6, 12 and 24h prior to seizures, showing that antiepileptic effects were short-term, almost disappearing 3h after administration. Our findings show that Vitamin D plays a direct anticonvulsant role in the brain and suggest that the Vitamin D endocrine system may represent a new target for the development of anticonvulsant drugs. [Copyright &y& Elsevier]

Abstract: Vitamin D insufficiency has been reported to be associated with increased blood cholesterol concentrations. Here we used two strains of VDR knock-out (VDR-KO) mice to study whether a lack of vitamin D action has any effect on cholesterol metabolism. In 129S1 mice, both in male and female VDR-KO mice serum total cholesterol levels were significantly higher than those in wild type (WT) mice (20.7% (P =0.05) and 22.2% (P =0.03), respectively). In addition, the serum high-density lipoprotein-bound cholesterol (HDL-C) level was 22% (P =0.03), respectively higher in male VDR-KO mice than in WT mice. The mRNA expression levels of five cholesterol metabolism related genes in livers of 129S1 mice were studied using quantitative real-time PCR (QRT-PCR): ATP-binding cassette transporter A1 (ABCA1), regulatory element binding protein (SREBP2), apolipoprotein A-I (ApoAI), low-density lipoprotein receptor (LDLR) and liver X receptor beta (LXRβ). In the mutant male mice, the mRNA level of ApoAI and LXRβ were 49.2% (P =0.005) and 38.8% (P =0.034) higher than in the WT mice. These changes were not observed in mutant female mice, but the female mutant mice showed 52.5% (P =0.006) decrease of SREBP2 mRNA expression compared to WT mice. Because the mutant mice were fed with a special rescue diet, we wanted to test whether the increased cholesterol levels in mutant mice were due to the diet. Both the WT and mutant NMRI mice were given the same diet for 3 weeks before the blood sampling. No difference in cholesterol or in HDL-C between WT and mutant mice was found. The results suggest that the food, gender and genetic background have an effect on the cholesterol metabolism. Although VDR seems to regulate some of the genes involved in cholesterol metabolism, its role in the regulation of serum cholesterol seems to be minimal. [Copyright &y& Elsevier]

Abstract: We investigated behavioural activity and temporal distribution (patterning) of mouse exploration in different open field (OF) arenas. Mice of 129S1 (S1) strain were subjected in parallel to three different OF arenas (Experiment 1), two different OF arenas in two trials (Experiment 2) or two trials of the same OF test (Experiment 3). Overall, mice demonstrated a high degree of similarity in the temporal profile of novelty-induced horizontal and vertical exploration (regardless of the size, colour and shape of the OF), which remained stable in subsequent OF exposures. In Experiments 4 and 5, we tested F1 hybrid mice (BALB/c-S1; NMRI-S1), and Vitamin D receptor knockout mice (generated on S1 genetic background), again showing strikingly similar temporal patterns of their OF exploration, despite marked behavioural strain differences in anxiety and activity. These results suggest that mice are characterised by stability of temporal organization of their exploration in different OF novelty situations. [Copyright &y& Elsevier]

Vitamin D is a neuroactive seco-steroid and its importance to the nervous system is receiving increasing recognition. Since numerous data link vitamin D dysfunctions to various neurological and behavioural disorders, we studied whether genetic ablation of vitamin D receptors (VDR) may be associated with motor impairments in mice subjected to several behavioural tests. The data obtained in the vertical screen and swim tests show that VDR genetic ablation produces severe motor impairment (shorter screen retention and poor swimming) in mutant mice compared to wild-type and heterozygous control animals. These impairments appear to be unrelated to visual, vestibular and activity/emotionality parameters of mice, and are likely associated with disturbed calcium homeostasis. This study confirms the important role of the vitamin D system in motor functions and suggests that animal genetic models targeting the vitamin D/VDR system may be a useful tool to study vitamin D-related motor/behavioural disorders. [Copyright &y& Elsevier]