Table 1.
Possible sources of poor reproducibility.
| Factor | Comment |
|---|---|
| sucrose solution | determination of sucrose concentration threshold to select the optimal concentration |
| water and food deprivation | effects on the metabolic state of the animal |
| stress susceptibility | stress-susceptible and stress-resilient animals |
| time of day | stressors are often used during light phase, which causes chronic sleep deprivation which affects the physiological state of animals |
| painful stressors | injections, immobilization, and other painful stressors which affects the physiological state of animals |
| social stress | behavioral effects of isolation, overcrowding, and hierarchical rank; different types and combinations of social stress in different laboratories |
| strain | different susceptibility to stressors |
| supplier | laboratory animal supplier and housing conditions; different susceptibility to stressors |
| handling | handling duration and familiarity with the experimenter |
| habituation | effects of repeated exposure to the same stressor even in an unpredictable manner |
| age | different susceptibility to stressors |
| sex | often males; different susceptibility to stressors |
| type of stressful factors | the combination of stressors of various modality, the order, and duration of presentation of each stressor |
| stress transmission | effects of visual, auditory, and olfactory sensations on animals |
| unaccounted factors | a large number of uncontrollable factors affecting the physiological state of animals |