The forced swim test is a rodent behavioral test used for evaluation of antidepressant drugs, antidepressant efficacy of new compounds, and experimental manipulations that are aimed at rendering or preventing depressive-like states. Mice are placed in an inescapable transparent tank that is filled with water and their escape related mobility behavior is measured. The forced swim test is straightforward to conduct reliably and it requires minimal specialized equipment. Successful implementation of the forced swim test requires adherence to certain procedural details and minimization of unwarranted stress to the mice. In the protocol description and the accompanying video, we explain how to conduct the mouse version of this test with emphasis on potential pitfalls that may be detrimental to interpretation of results and how to avoid them. Additionally, we explain how the behaviors manifested in the test are assessed. Video LinkThe video component of this article can be found at http://www.jove.com/video/3638/ Protocol 1. Materials and Method The water tanksThe cylindrical tanks (30 cm height x 20 cm diameters) required for the mouse forced swim test (FST) in our laboratory are constructed of transparent Plexiglas, as this material is able to withstand the frequent movement of the tanks and accidents better than glass. The water level is 15 cm from the bottom and should be marked on the tank to ensure that the volume of water is consistent across mice. The number of tanks should ideally be at least twice as many as the number of mice being tested at a time, so that the second water tank set can be filled while the first set is in use. The dimensions of the tanks should be selected in a way that the mice will not be able to touch the bottom of the tank, either with their feet or their tails, during the swimming test. The height of the tank should be high enough to prevent the mice from escaping from the tank. Please note that the diameter of tank and the depth of water are important parameters that can be adjusted to change the behavior of mice (for a detailed analysis of these issues see 1-3 ). ThermometerA water resistant infrared thermometer is preferable, since rapid measurement of temperature reduces the amount of time required to conduct the test. However, a glass mercury thermometer will also be sufficient for this task.

The tail-suspension test is a mouse behavioral test useful in the screening of potential antidepressant drugs, and assessing of other manipulations that are expected to affect depression related behaviors. Mice are suspended by their tails with tape, in such a position that it cannot escape or hold on to nearby surfaces. During this test, typically six minutes in duration, the resulting escape oriented behaviors are quantified. The tail-suspension test is a valuable tool in drug discovery for high-throughput screening of prospective antidepressant compounds. Here, we describe the details required for implementation of this test with additional emphasis on potential problems that may occur and how to avoid them. We also offer a solution to the tail climbing behavior, a common problem that renders this test useless in some mouse strains, such as the widely used C57BL/6. Specifically, we prevent tail climbing behaviors by passing mouse tails through a small plastic cylinder prior to suspension. Finally, we detail how to manually score the behaviors that are manifested in this test.

OBJECTIVE-Perturbations to the prenatal environment have been associated with the development of adult chronic disease, findings that gave rise to the "Barker Hypothesis" or the "developmental origins of adult disease" concept. In this study, we used an animal model to determine the metabolic consequences of maternal prenatal stress and high-fat feeding on the developing offspring. RESEARCH DESIGN AND METHODS-Pregnant femaleSprague-Dawley rats were maintained on standard chow or 60% high-fat diet throughout gestation and lactation. Half of each group were exposed to a novel variable stress paradigm during the 3rd week of gestation, whereas control dams were left undisturbed. Body weight, body composition, glucose tolerance, and endocrine parameters were measured in offspring through early adulthood.RESULTS-Male and female pups from dams that experienced prenatal stress and/or were on a high-fat diet weighed more beginning on postnatal day 7 compared with standard chowcontrol pups. Access to high-fat diet at weaning increased the body weight effect through early adulthood and was attributable to greater adiposity. Pups weaned onto standard chow diet showed no significant difference in glucose clearance or insulin secretion. However, pups weaned onto high-fat diet had impaired glucose tolerance if their dams were on a high-fat diet, experienced prenatal stress, or both.CONCLUSIONS-Our data demonstrate that prenatal stress and/or high-fat diet during the intrauterine or postnatal environment affects offspring in a manner that increases their susceptibility to diet-induced obesity and leads to secondary adverse metabolic consequences.

Maternal high-fat (HF) diet throughout gestation and suckling has long-term consequences on the offspring’s metabolic phenotype. Here we determine the relative contribution of pre- or postnatal maternal HF diet on offspring’s metabolic phenotype. Pregnant Sprague-Dawley rats were maintained on normal chow or HF diet throughout gestation and suckling. All litters were cross-fostered to chow or HF dams on postnatal day (PND)1, resulting in four groups. Body weight, body composition, and glucose tolerance were measured at weaning and in adulthood. Leptin sensitivity was assessed by signal transducer and activator of transcription (STAT)3 activation on PND10 and PND21. Pups cross-fostered to HF dams gained more body weight than chow pups by PND7 and persisted until weaning. Postnatal HF pups had greater adiposity, higher plasma leptin concentration, impaired glucose tolerance, and reduced phosphorylated STAT3 in response to leptin in the arcuate nucleus at weaning. After weaning, male offspring cross-fostered to HF dams were hyperphagic and maintained greater body weight than postnatal chow pups. Postnatal HF diet during suckling continued to impair glucose tolerance in male and female offspring in adulthood. Maternal HF diet during suckling has a greater influence in determining offspring’s metabolic phenotype than prenatal HF diet exposure and could provide insight regarding optimal perinatal nutrition for mothers and children.