Methamphetamine (Meth) is a neurotoxin that primarily effects dopamine pathways in the brain. Meth mimics dopamine which is called the “pleasure” neurotransmitter in the brain. When something pleasurable happens, certain axons in the brain release dopamine which attach to receptors on dendrites of neighboring axons passing along the pleasure message in the brain. The process is stopped when dopamine is released from the receptors and pumped back into the neuron that released it where it is stored for later use.
Usually neurons recycle dopamine, but methamphetamine is able to fool neurons into taking it up just like it would dopamine. Once inside the neuron, methamphetamine causes that neuron to release lots of dopamine. This causes the person to feel intense pleasure that can last all day. Eventually these pleasurable sensations stop, causing unpleasant feelings called a “crash” that leads a person to crave more of the drug. Over time the person has a difficult time feeling any pleasure.
Methamphetamine can also change other neurotransimitter pathways in the brain including serotonin and epinephrine which affect mood, energy, and self-regulatory mechanisms of heart rate, respiratory rate and blood pressure.
– Susie Adams, PhD, PMHNP Director, VUSN Psychiatric Mental Health Nurse Practitioner Program