Final answer:
Most drugs increase the production or activity of neurotransmitters in the brain, such as dopamine, which is often associated with reward and pleasure, and GABA, which has a calming effect. Stimulants like cocaine and amphetamines enhance dopamine activity, while drugs like ethanol and benzodiazepines increase GABA activity.
Step-by-step explanation:
Most drugs increase the production of neurotransmitters in the brain, particularly those that play a role in mood, thinking, perception, and behavior. One common neurotransmitter affected by many drugs, including stimulants, is dopamine, which is associated with the brain's reward and pleasure centers. Stimulants such as cocaine, amphetamines, and nicotine act as agonists of the dopamine system, enhancing the activity of this neurotransmitter and leading to increased alertness, pleasure, and often, addictive tendencies.
Another example of a neurotransmitter affected by drugs is GABA, which normally has an inhibitory effect on nerve cells. GABA agonists, like ethanol, barbiturates, and benzodiazepines, increase the activity of GABA, leading to calming and sedative effects. The action of drugs on neurotransmitters can either stimulate or inhibit neural activity depending on the type of drug and the neurotransmitters it affects.