(1) Behavioral despair model
The behavioral despair model is simple, fast and sensitive, and is usually used for rapid screening of antidepressants. It mainly includes two animal models. The first is a forced swimming experiment in rats and mice. The mouse is forced to swim in a limited space. First, it desperately tries to swim and escape, then exposes its nostrils to keep breathing while remaining still and floating. He sometimes patted his limbs to prevent his body from sinking, but this situation is called immobility, and actually gave up the hope of escape, which is "behavioral despair." The second is the tail suspension experiment of mice. The tail-suspended mice struggle to overcome the abnormal posture, but after constant movement, they will intermittently stand still and show a state of "despair". Most antidepressants can effectively reduce fatigue in mice during transportation.
(2) learned helplessness (LH) model
Acquired helplessness is a type of mouse that can avoid electric shocks after being exposed to uncontrollable or predictable aversive stimuli (such as electric shocks). In the environment, the lack of escape behavior may be accompanied by loss of appetite, weight loss, reduced physical activity, and reduced aggressiveness. Various clinically effective drugs and treatments for depression can reverse the phenomenon of "acquired fatigue". This model is very sensitive to antidepressants, and the time course of its pharmacological action is consistent with clinical models, making it an ideal model for depression research. It can be used not only to screen antidepressants, but also to study the mechanism of action of such drugs and the neurobiology of depression.
(3) Chronic Unpredictable Stress (CUS) Model
Rats will experience a series of severe stresses (noise, strong light stimulation, long-term behavioral restrictions, etc.), and subsequently exhibit reduced activity. Throughout the experiment, several different sources of stress were randomly applied so that the animals could not predict the start of the stimulation. It mainly simulates anhedonia, which is the main symptom of depression in humans. It also mimics the symptoms of other major depressions. Impaired athletic ability and social ability, impaired exploratory behavior, lack of aggressiveness and aggressiveness, reduced sexual behavior, etc. An efficient model that can last for several months basically meets the requirements of the depression model and has been widely used in foreign literature.
(4) Chronic Mild Stress Disorder (CMS)
This method involves placing the animal (rat or mouse) in a mildly stressed environment (electric shock on the soles of the feet, overnight lighting, no water). Or, random selection of various stimuli, such as fasting, changing cages, rotating day and night, after weeks or months (usually 3 weeks), the animal is unpredictable, and with the reduction of vertical activity and consumption of sugar and water The decrease in psychiatric levels and the resulting depression, loss of interest and anhedonia are common clinical changes in psychomotor status and depressed patients. It's like losing interest. In addition to behavioral changes, the rats in this model also have sleep structures, hyperthalamus-pituitary-adrenal cortex (HPA) axis hyperactivity, and immune system changes. This model is now considered to be one of the most classic models and is widely used to study the pathophysiological mechanism of endogenous depression, the mechanism of drug action and various treatment methods. The animals reported in the CMS sham model include C57BL/6 mice, SD rats, FSL rats and LH rats. The pregnancy stress-induced depression model of offspring SD rats exposed to prenatal stress conditions includes behavioral anxiety, adult behavior (such as HPA axis, neuroendocrine) and continuous changes in sleep structure. Experience high functional, paradoxical sleep increases, and is highly correlated with plasma corticosterone levels. The significant changes in sleep are similar to those in patients with depression. In particular, sleep changes are more characteristic than other models.
(5) Social frustration model
The most representative model is the goat depression model, which artificially paired male hamsters in the same environment. There are "strong" and "weak" points between the two mice. In front of the "strong" mouse, the "weak" mouse showed weight loss, decreased spontaneous activity, HPA axis, sympathetic hyperactivity... these Some of the symptoms can be relieved with a certain amount of antidepressants. It is a widely used and researched model of depression, which can be used to study the pathophysiological mechanism of depression and the mechanism of action of antidepressants.