How drugs affect the nervous system?

Answer 1

Depressant Drugs:

Alcohol, Benzodiazepines, Barbiturates and other central nervous system depressant drugs act primarily on a neurotransmitter substance known as GABA (Gamma Aminobutyric Acid). GABA is an inhibitory neurotransmitter that makes other neurons less likely to activate. The depressant drugs are GABA agonists, acting to help GABA reduce neuronal activation more efficiently than it usually would. Alcohol also inhibits (acts as an antagonist against) another excitatory neurotransmitter (Glutamate), making it harder for Glutamate to get the nervous system excited.

Stimulant Drugs

Amphetamines have their primary effects on the neurotransmitter Dopamine. Amphetamines both induce the terminal button of Dopamine-producing neurons to let more Dopamine out than normal, and also keep that Dopamine out in the synapse longer than it normally would be allowed to stay. Amphetamine also acts agonistically on receptors for a different neurotransmitter, Norepinephrine, by competing with Norepinephrine for post-synaptic receptors and turning those post-synaptic receptors on.

Cocaine has its major effect by blocking the re-uptake of the neurotransmitters Dopamine and Serotonin.

Opioid Drugs:

Opioid drugs bind to special endorphin receptors in the brain (the 'mu', 'kappa', 'sigma' 'delta' and 'gamma' receptors) that have to do with pain. When these receptors are occupied and activated, the perception of pain lessens.

Drug treatments for opioid addictions sometimes include the administration of Naltrexone, which is an opioid antagonist. Naltrexone competes with the opioids for their receptor sites, but is not itself capable of activating those receptor sites. An opioid addict on Naltrexone is thus rendered more or less incapable of getting high from their opioid drug of choice; they may take an opioid, but it will be blocked from the opioid receptors by the Naltrexone, and will not have its effect.

Cannabinoids:

Marijuana has a complex set of effects. It acts on the neurotransmitters Serotonin, Dopamine and Acetylcholine. It also binds to a receptor for a recently discovered neurotransmitter known as Anadamide.

Hallucinogens:

LSD is known to antagonize Serotonin by blocking its release.