Open-field arena

The behavior of tacl mice was also analyzed in several animal models of anxiety. The open-field test is a widely used tool for behavioral research, but less specific for the evaluation of the anxiety state of the animal, because it is a summation of the spontaneous motor and the exploratory activities, and only the latter is influenced by the anxiety level (Choleris et al. 2001). Under aversive environmental conditions (high level of illumination) the animals activity is strongly affected by the emotional state, while less aversive situations (familiar, dimly lit environment) are useful to assess the general motor activity of mice. Because rodents avoid open areas, the activity of mice in the central part of the open-field arena is inversely correlated to the anxiety level. Tad mice spent only 6.5% of their total activity in the central part, which represented 11% of the total field, indicating that they avoided this aversive area, hi contrast, tacl mice spent 13.6% of their activity in the central area (Bilkei-Gorzo et al. 2002). The increased central activity of the tad mice indicates that the test situation was anxiogenic for tad animals, but less so for the knockout mice. 

After the apparatus is divided into central and peripheral zones, mice are placed consistently in a corner, or the center of the open field arena, and allowed to explore for 5-10 min. 

This exercise is the second of the two experiments deahng with communication via scent marks in mice. In this Open-field Test, we observe scent marking behavior of male mice in response to presence or absence of urine stimuli in their environment. (In fact, the open field arena is enclosed and covered.)... 

Use an open-field arena that has 8x8 square tiles. Hurst (1988, 1989) used an arena 1.2 x 1.2 m large with 15 x 15 cm tiles. (One commercially available arena has 7x7 tiles, but will work, too). We will divide the arena into four quadrants (these may not be of entirely equal size see above). We will run two tests. 

Data Sheet 21.1 Behavior of mice in open field arena... 

The open field is one of the oldest models used for the study of emotionality in animals, and was used for the first time in 1934 by Hall. The procedure consists in observing locomotor activity, rearing, freezing, and defecation by animals subjected to a circular arena divided into 12... 

The procedure used was essentially that described by Brimblecombe (1963) except that the open field employed was similar to that of Broadhurst (1957). The arena was circular with a diameter of 82 cm, and was illuminated by four 150 W lamps, 137 cm above the base. White noise of 88 dB was used and the operator was screened from the rat by a muslin curtain. 

CA has been used for centuries in Ayurvedic medicine for psychoactive purposes to control anxiety and help in relaxation and mental calmness. Various studies and evaluations by human and animal models have confirmed the potential claim of CA and its triterpenoid centellosides in anxiolytic activity. In animal studies, the methanolic and ethyl acetate extract of CA as well as the AS of the plant have been reported to possess anxiolytic activity in rat behavioral models [51], In elevated plus maze study, CA methanol extract (3,047 mg kg of body weight) and AS (3 and 5 mg kg ) significantly reduced the number of closed arm entries and increased the time spent in protected head dips, whereas both CA ethyl acetate extract (111 mg kg ) and AS (3 and 5 mg kg ) significantly increased the number of protected head dips and the time spent for this activity. For the open-field test, AS (3-10 mg kg ) significantly increased the rat spent time (41.3 s) at the center of the arena, while the social interaction test treatment with 1 and 3 mg kg of AS significantly reduced the number of non-interaction activity by 29.8 s and 35.0 s, respectively. 

In this work we compare some of the major results from two field expeditions to the Southern Ocean region. The first expedition was a ship cruise between Punta Arenas/Chile and the west coast of the Antarctic Peninsula, which was conducted during the austral fall season (March 20 - April 28, 1986) as part of the United States Antarctic Research Program (USARP). Details of the ship cruise and a complete discussion of the results have been published elsewhere (12). The second expedition consisted of a series of flight measurements off the west and south coast of Tasmania during the austral summer season (December 3-18, 1986). We discuss preliminary results from 2 of 8 flights which were conducted in marine air masses behind cold fronts moving over the open ocean. 

For nearly 30 years, the field of metal clusters has provided chemists a vast arena in which to work. Early results were often surprising. Crystallographic analysis revealed that compounds, such as Os3(CO)j2 and Rh6(CO),g, were often incorrectly formulated by traditional techniques. " It was quickly evident that a large number of ligand-stabilized metal clusters could be synthesized, and extensive exploratory research opened a rich, interesting field. Discovery of unprecedented structural features was the norm and remains common. The fact that each platonic solid (namely, the tetrahedron, octahedron, cube, icosahedron, and pentagonal dodecahedron) is now represented in transition metal cluster chemistry illustrates the structural variety present in this class of compounds. A short preview of particular metal clusters whose geometries approximately conform to these Platonic solids provides an introduction to some of the structural phenomena considered elsewhere in this chapter. 

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