Mice are susceptible to the effects of psychoactive substances that alter mood and perception in humans. While their subjective experience cannot be definitively known, their responses share many similarities with human reactions, making them valuable subjects for scientific study.
How Drugs Affect Mouse Physiology
Drugs influence mouse physiology by interacting with their nervous systems, which share many similarities with human neural pathways and often target neurotransmitter systems like dopamine, serotonin, and GABA. For instance, cocaine inhibits the dopamine transporter (DAT), increasing dopamine levels in the brain’s reward pathways, a mechanism also observed in mice. Mice possess cannabinoid receptors (CB1 and CB2) affected by cannabis compounds. Alcohol impacts GABA and glutamate neurotransmitters, enhancing GABA’s inhibitory effects and reducing glutamate’s excitatory actions. These interactions alter neuronal activity and contribute to the observable effects of these substances.
Observable Effects of Common Substances
When mice are exposed to psychoactive substances, they exhibit a range of observable behaviors and physical changes. After exposure to cannabis high in Δ9-THC, mice may show reduced movement, altered coordination, and antinociceptive (pain-reducing) effects. The effects on anxiety can vary depending on the strain and dose of THC, with some studies showing anxiogenic (anxiety-producing) effects and others anxiolytic (anxiety-reducing) effects.
Alcohol consumption can lead to observable signs of intoxication, such as wobbling and slower movement. Mice become “tipsy” and wobbly after an alcohol dose. Stimulants like amphetamines significantly increase locomotor activity and lead to stereotyped behaviors, such as repetitive movements. These behavioral changes are dose-dependent, with lower doses increasing general activity and higher doses inducing more focused, repetitive actions.
Mice in Drug Research
Mice are used extensively in scientific research to study drug effects, including psychoactive substances. Their genetic makeup is highly similar to humans, with approximately 95% of protein-coding genes being identical, enabling researchers to model human diseases and drug responses; they also have a relatively short lifespan of 2-3 years and reproduce quickly, allowing the study of long-term drug effects and multiple generations. Their small size and ease of housing make them cost-effective and convenient for controlled laboratory experiments, and scientists can genetically modify mice to carry genes associated with human diseases or to turn specific genes on or off, providing valuable insights into how drugs interact with biological systems. This makes mice an important model for assessing drug safety and efficacy before human clinical trials.