The Sucrose Preference Test is conducted base on the natural preference of rodents for sweet water. It studies the lack of pleasure in depression disorders by observing the decrease in the animals’ preference for sugar water. The lack of pleasure, also call as Anhedonia, refers to the inability to obtain happiness in rewarding or enjoyable activities, and a lack of interest in rewarding stimuli. Anhedonia is one of the core features of human depression disorders.
Place the rodent in animal cages, 1% to 2% sucrose water and regular drinking water were provided simultaneously to the animals. If the animals’ preference for the sugar water decreased, it indirectly indicated that the animals might have an anhedonia, which can be used as an important criterion for evaluating the effectiveness of the depression model. Antidepressant drugs can restore the animals’ preference for sugar water.
Therefore, in various studies, it shows Sucrose Preference Test is widely in used in assessing motivation, depression (and anhedonia) and related emotional states etc.
However, during the traditional Sucrose Preference Test, researchers often encounter the following series of problems. It this article, we will share with you the difference of traditional manual operation and our automated Sucrose Preference Test.
Manual Sucrose Preference Test VS Automated Sucrose Preference Test
In terms of Operation
Manual operation is cumbersome
In manual operation, researchers need to frequently change the sucrose water bottles and clear water bottles.
After each bottle change, thorough cleaning and disinfection are also required to prevent cross-contamination.
Manual operation is lack of real-time monitoring
Manual operation cannot provide real-time information on the animals’ drinking behavior. Researchers can only check the scale changes of the bottles at certain intervals (such as every few hours or daily) to estimate the animals’ water intake.
Manual operation is difficult to operate multiple channels simultaneously
When conducting sucrose water preference experiments on multiple groups of animals simultaneously, manual operation finds it hard to achieve synchronized operation.
In terms of Data accuracy
Manual operation results in large data deviations and errors.
Manual reading of the scale to measure the consumption of liquid is prone to errors. In manual sucrose preference test, the evaporation of liquids is also a problem that cannot be ignored. During the experiment, sugar water and pure water will evaporate due to environmental factors such as temperature, humidity and air flow, which leads to the recorded liquid consumption being higher than the actual intake of the animals.
Manual operation comes with interference with animal stress responses
In manual operation, animals need to be frequently removed from their cages for operations such as weighing or changing water bottles, which may lead to abnormal responses to sugar water, making the experimental data unable to truly reflect the animals’ preferences under normal conditions.
Manual operation lack of detail data
Manual operation can only provide relatively simple data, such as the total consumption of sugar water and pure water. However, more detailed data on drinking behavior, such as the duration of each drinking episode, the intervals between drinks, and changes in drinking preferences at different times of the day, cannot be obtained. These data are crucial in studying the drinking motivation of animals, their taste perception, and the precise impact of drugs on drinking behavior.
What is automated Sucrose Preference Test?
SANS automatic sucrose preference test uses the micro injection pump for water supply and has the advantages of real-time statistics, automation, and high accuracy. It significantly improves the efficiency of drug research and basic life science research, and fundamentally reduces data deviations and errors caused by manual operations.
One channel can record 2 drinking water status at the same time. Our software can support a maximum 200 channels SPT. Adopts Micro Syringe Pump for precise filling sucrose water/water, accuracy 0.01ml. Injection speed 0.1-5ml/min, syringe volume 20-50ml. Software supports “one-click bottle change”. Software can automatically filter the interference of liquid volatilization on the test data. Drinking water events can be synchronized to third-party devices through TTL signals. Drinking time accuracy 0.01s, drinking volume accuracy 0.001ml. Animal information: Name, Group, Age, Sex, Notes. Modular design on drinking water detection, which is convenient for position exchange. Support long-term test, water change during the test is available. Natural housing cage to reduce animal stress reaction. Separate channel operation to ensure stability of other channels.
Experimental Process
Preliminary preparation
Select adult male C57BL/6 mice (8-10 weeks old) and keep them in single cages to acclimate to the laboratory environment for 1 week. Test the conductivity of the metal mouth to ensure the sensitivity of the licking signal (false touch rate <1%); pre-experiment to verify the baseline of the number of licking water from sugar water and ordinary water bottles (the sucrose water preference rate of healthy mice is >65%).
Acclimation period
Animals need to adapt to the experimental environment and the double water bottle apparatus, usually 12-24 hours. Baseline test: Record the sugar preference index under normal conditions (sugar consumption/total fluid consumption × 100%). Intervention treatment: such as drug injection, chronic stress, etc., followed by re-measurement of the preference index.
Final Test
The experimental group received an intraperitoneal injection of fluoxetine (10 mg/kg), and the control group received an injection of normal saline; the animals were fasted for 4 hours after administration (only drinking water was provided); sugar water and ordinary water bottles were provided, and the number of water lickings was recorded continuously for 24 hours; and time-specific data were analyzed (e.g., 0-4 hours vs. 4-24 hours after administration).
Evaluation
Sucrose preference index = sucrose water consumption/(sucrose water consumption + drinking water consumption) x 100%.
Summary
SPT experiment is very sensitive to environmental changes, which is a key factor affecting the success of the experiment. The test should be carried out in a separate room, keep the environment quiet, and maintain appropriate temperature and humidity during the experiment.
During the baseline test phase, animals that have been trained multiple times but whose baseline is still unstable or that drink too much or too little water need to be eliminated.
The sucrose water preference experiment can evaluate whether the depression model animals have the core symptom of human depression – anhedonia, and has a high degree of credibility.
