| First, the purpose of the experiment  1. Learning mouse learning and memory behavior detection method  2. Learn how to use the mouse to avoid dark automatic tester.  3. Understand some of the factors that influence learning and memory.  Second, the experimental principle  Rodents are nocturnal animals, prefer dark places, and avoid bright places. It will try to escape to the dark, where it is given electrical stimulation in the dark, and the mouse will be forced to flee back to the bright spot and gain memory. The experiment designed according to this principle is a one-time passive avoidance reaction experiment.  Passive Avoidance Response is an animal model developed in the late 1960s that is commonly used to detect the ability of small animals to learn and remember. Response characteristics: Animals must learn to avoid terrible events while inhibiting their natural nature. Passive avoidance reactions include: avoidance method (also known as step-through test) and platform-down method (also known as step-down test).  Third, experimental equipment  The mice are commonly used with surgical instruments, sodium nitrite, scopolamine (Scop.), saline, and 35% alcohol.  Fourth, the experimental steps  1. Experimental instrument for learning and memory behavior of small animals - avoiding darkness  The mouse darkening automatic tester consists of two parts, a controller and a movable box, which can simultaneously test 6 mice. There is a small door between the light and dark experiment box for the animals to enter and exit. When the animal enters the dark room and is shocked, it can automatically record the incubation period of the mouse entering the dark room from the bright room and the number of electric shocks. It can also flexibly select the stimulus by pressing the button. Voltage and set experiment time.  2. Experimental procedure:  2.1 Adaptation: Put the animal head into the chamber to the chamber, open the door between the two chambers, let the animals move freely in the two chambers for 2-3 minutes, remove them and put them back in the cage.  2.2 Training: The next day, the animal was placed in the bright room, which quickly penetrated into the darkroom, the door opening connecting the two rooms was closed, and the electric stimulator was activated, and the animal's foot was shocked. If the animal does not enter the darkroom for more than 100 seconds during the first training session, knock it out or gently rush it into the darkroom.  Record indicators:  (1) Record the incubation period of the animal from the bright room into the dark room, which can be used as an indicator to determine whether the animal behavior has changed after administration. If the drug caused the animal to calm down, the incubation period was significantly longer than the control group.  (2) Record the reaction of the animal after electric shock, such as violent barking and jumping, rated as A-level reaction; weak scream, rated as B-level reaction; not called, rated as C-level reaction. Animals generally jump after being shocked. The C-level reaction is often accompanied by animal jumping. Although the animal does not scream, normal animals can feel the shock of electric shock and show good memory results. Grade C reactions are more common in male animals. Grade A reactions are more common in female animals. This record can be used as an auxiliary indicator of whether the animal's pain domain changes.  2.3 Heavy test: 24 hours after training (the third day), the animals were again placed in the bright room for retesting.  Record indicators:  (1) Record the incubation period of animals entering the dark room, which is step through latency (STL). The maximum latency is set to 300 seconds.  (2) Record the number of errors that the animal entered the darkroom within 300 seconds, including the number of times the first error entered the darkroom.  Experimental design example  According to the information theory, the memory is simply divided into: the acquisition of memory (that is, the learning process, the process of obtaining information), the consolidation of memory (the process of keeping information), the reproduction of memory (the process of extracting information), we can filter accordingly Cognitive drugs that act at different stages of memory.  The drugs that give memory to the injured animals before, after or after the retest can observe the effects of the drugs on different stages of memory separately. Before the animals are tested for cognitive drugs, the cognitive drugs can be judged according to the experimental results. The effect of the damaged drug. In order to simplify the screening work, a small animal learning and memory test method with less experimental steps is often used, and the step-in method is taken as an example. The principle is as shown.  Adaptation --- training (shock) --- (after 24 hours) --- retest (no electric shock)  Influence impact  Memory gains memory, consolidates memory reproduction  First, the memory acquisition process  1. Establish a model of memory impairment:  15-20 minutes before the animal was subjected to electric shock training, the animals were intraperitoneally injected with scopolamine hydrobromide (HBr-Scopalamine), and the mice: 3 mg/kg. During the training, the residence time in the bright room was slightly longer than that of the control group, and the response when subjected to electrical stimulation after entering the dark room was similar to that of the control group: barking or jumping. After 24 hours, when the animals were placed in the bright room again, the incubation period of the animals into the dark room was significantly lower than that of the control group, that is, a successful memory impairment model was prepared.  2. Taking the drug to be tested:  According to the peak time of the drug to be tested in the animal, the animal is given the drug at the corresponding time, such as oral medication, the animal can be administered with the drug to be tested 1 hour before the training, and then the animal is damaged for 15-20 minutes before the training. Obtained drugs, such as scopolamine hydrobromide.  Second, the memory consolidation process  1. Establish a memory consolidation barrier model:  Animals were given intraperitoneal injection of the protein synthesis inhibitor cycloheximide (Cycloheximide, mouse: 90-100 mg/kg) to inhibit protein synthesis, or subcutaneous injection of NaNO2 (mouse: 120 mg/kg). Sexual hypoxia, or the animal is given an electric shock in the head. Then put it back into the breeding box and retest it after 24 hours.  2. Taking the drug to be tested:  In the case of oral medication, the animal is administered with the drug at the peak of the drug action (usually 1 hour before) during the electric shock training. If the drug is injected intraperitoneally, it is usually injected half an hour before training. The animal is then subjected to electric shock training. Immediately after training, the memory is congested to consolidate the drug or other experimental factors. After 24 hours, the test can be repeated to detect the antagonistic effect of cognitive drugs on memory consolidation disorders.  Third, the memory reproduction process of small animal learning and memory behavior detection technology - the dark method  1. Establish a memory reconstruction disorder model  Mice were dosed with alcohol (35%, 0.1 ml/10 g mouse weight) 15 minutes prior to animal weight testing and retested after 15 minutes. It can be seen that the memory extraction process of mice is damaged.  2. Taking the drug to be tested: The animal is orally administered with the drug to be tested 1 hour before the animal is tested.  note:  The injury only works when the alcohol is administered for 10-30 minutes before the retest, and the time is longer than 30 minutes.  This dose of alcohol only has a damaging effect on less consolidated, one-time memory, but has no effect on the reproduction of the more consolidated memory that mice need to undergo multiple trainings.  Attachment: step-down test  Experimental principle:  Depending on the animal's habits, rodents will stay in the open space for most of the time. When placed on a high platform, it will quickly jump off instinctively, avoiding the wall or the corner. The bottom of the platform can be energized with an insulated jumper. Animals receive electric shocks during training and jump on the platform to avoid electric shocks, thus gaining memory. When the memory of the animal declines, it shows that the latency of jumping from the platform for the first time is shortened, and the number of jumps is increased. When the memory of the animal is enhanced, the incubation period of the jump is prolonged, and the number of electric shocks is significantly reduced.  Experimental procedure  1. Adaptation: Place the animals on the platform so that the animals can freely adjust up and down within the box for 2-3 minutes, then return the animals to the feeding box. Or adapt to 10 seconds each time, a total of 3 times, 30 minutes apart. The latter makes the animal more adaptable to the experimenter's gestures and the entire experimental process than the former.  2. Training: It can be done immediately after adaptation, or 24 hours after adaptation.  Put the animal on the platform again, and turn on the electric stimulator at the same time. As the animal adapted in the box, it almost jumped off the platform immediately, and the limbs were immediately shocked. Due to the pain of the electric shock, the animal jumped up and down, occasionally jumping back to the platform unintentionally, and immediately jumped off the platform, so many times.  Recording Indicators: Detection Techniques for Learning and Memory Behavior of Small Animals  1) the incubation period of the animal from the platform to the platform;  2) The number of times the animal repeatedly steps down can represent the academic performance of the animal;  3. Retest:  The test was repeated 24 hours after the training, and the animals were placed on the platform again to observe the animal's dismounting.  Record indicators:  The number of times the animal has jumped from the platform to the platform and jumped off the platform within 5 minutes. This is the animal's memory score.  |
Labour protection glove
Labour Hand Gloves,Leather Hand Gloves,Leather Working Gloves,Labour Protection Glove
Shandong Binzhou Yong'an Labor Protection Factory , https://www.zhuqiangsafetybelt.com