Table 1 – Neurotransmitters Implicated in Drug Use and Addiction
| Neuro- transmitter | Distribution in the Central Nervous System | Drugs That Affect It |
|---|---|---|
| Serotonin | Midbrain VTA Cerebral cortex Hypothalamus | MDMA (ecstasy) LSD Cocaine |
| Norepinephrine | Midbrain VTA Cerebral cortex Hypothalamus | Cocaine Methamphetamine Amphetamine |
How do psychoactive drugs affect neurotransmitters?
The drug affects three neurotransmitters in the brain: serotonin, dopamine, and norepinephrine (or noradrenaline). When the drug enters the brain, it leads to these neurotransmitters being released from their synaptic vesicles in neurons. This results in increased neurotransmitter activity.
Do drugs prevent the release of neurotransmitters?
Other drugs, such as amphetamine or cocaine, can cause the neurons to release abnormally large amounts of natural neurotransmitters or prevent the normal recycling of these brain chemicals by interfering with transporters. This too amplifies or disrupts the normal communication between neurons.
What drug inhibits a neurotransmitter release?
A reuptake inhibitor (RI) is a type of drug known as a reuptake modulator that inhibits the plasmalemmal transporter-mediated reuptake of a neurotransmitter from the synapse into the pre-synaptic neuron.
What happens to neurotransmitters when a drug is not present?
Normally, when drugs are not present, the cycle of release, breakup, and neuron re-entry maintains the amount of neurotransmitter in the synapse, and hence neurotransmission, within certain limits. In most cases, when an addictive drug enters the brain, it causes neurotransmission to increase or decrease dramatically beyond these limits.
What are some drugs that mimic neurotransmitters?
Some drugs mimic neurotransmitters. Heroin and prescription opioids, for example, chemically resemble the brain’s natural opioids (endorphin and enkephalin) sufficiently to engage and stimulate their specialized receptors.
How do drugs affect neurons?
Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter. This similarity in structure “fools” receptors and allows the drugs to attach onto and activate the neurons.
How does marijuana interact with neurotransmitters?
Marijuana mimics cannabinoid neurotransmitters, the most important of which is anandamide. Nicotine attaches to receptors for acetylcholine, the neurotransmitter for the cholinergic system. Other drugs alter neurotransmission by interacting with molecular components of the sending and receiving process other than receptors.
