How does amphetamine affect neurotransmitter levels in the brain?

Amphetamines primarily increase levels of dopamine and norepinephrine in the brain. This occurs through several mechanisms, including the promotion of the release of these neurotransmitters from their storage vesicles in presynaptic neurons and the inhibition of their reuptake into the neurons. When dopamine and norepinephrine levels are elevated, it leads to heightened alertness, increased energy, and improved mood, contributing to the stimulating effects associated with amphetamine use.

Dopamine is particularly significant because it is involved in the brain's reward pathways, reinforcing behaviors that feel pleasurable. Norepinephrine plays a vital role in the body's response to stress, affecting attention and arousal.

Other options are less accurate; for instance, while serotonin can be affected by various substances, amphetamines specifically target dopamine and norepinephrine, making the assertion that they decrease serotonin levels misleading. Additionally, while amphetamines do influence neurotransmitter reuptake, they do not block all neurotransmitters, as different substances may affect different neurotransmitter systems. Therefore, the assertion that amphetamines only affect serotonin levels is an oversimplification of their pharmacological effects.