Elevated cross maze experimental method and precautions
ã€laboratory apparatus】
ã€experimental method】
Place the rat in the center of the maze with the head facing the open arm and the observer at least 1 m from the center of the maze. The number of times the rats entered the open arms and the closed arms and the retention time of the arms in the experimental period (usually 5 min) were recorded separately (the criteria for the entry and exit arms should be strictly defined, with all limbs or two forepaws coming out). Calculate the percentage of the number of times the rat enters the arm and the time of staying in the arm, respectively, the total number of times (the sum of the number of open arms and closed arms) and the total time (the sum of the retention time of the open arms and the closed arms). An indicator of anxiety. Usually these two indicators are highly correlated. An agent is considered to have an anxiolytic effect if it increases the animal's preference for the open arm (ie, increases the number of times it enters the open arm and the percentage of time spent in the open arm) without changing the total number of times the arm enters. Similarly, if the drug reduces its preference for the open arms while not changing the total number of arms into the arm, the drug is considered to have an anxious effect.
ã€Precautions】
(1) In order to increase the total number of times the rat enters the arm and avoid the rat hiding in the closed arm, the rat is usually placed in the open field for 5 minutes before being placed in the maze. The animal 1-2 min per day for 5-7 days before the experiment also reduced the effect of irrelevant stress stimuli on the experiment.
(2) The total number of arms involved reflects the locomotor activity of the animal. The evaluation of the effect of the drug on the anxiety state should be carried out without changing the total number of arms. If a treatment reduces the animal's preference for the open arms and the total number of arms in a similar manner, then it is necessary to make an analysis of covariance to determine whether it is an anxiety or sedation. Considering that there is a certain correlation between the total number of arms and the above two anxiety indicators, Pellow and Lister suggested using a holeboard apparatus to measure the animal's motor activity, followed by a labyrinth experiment.
(3) The elevated cross maze has some face validity, and the animal is reluctant to explore the result of the joint action of the labyrinth open arms may be due to the fear of the open space of the rodent and the elevation of the maze. Know which of these two factors predominate in anxiety.
(4). Male or female large mice or male gerbils can be used. Each animal was tested only once, and it was better to knock out the animals in the experiment. If a narrow flange is placed around the open arm to prevent falling, the sensitivity of the evaluation against anxiety drugs will be reduced.
For details, please refer to the company's website and the experimental blog: blog.sina.com.cn/softmaze.
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