Stimulants

[Grievar]

Question: How do stimulants like caffeine, nicotine, cocaine, and
amphetamines supposedly “calm you down”, and are used as
anaesthetics at times?

[scm1001]

part of the effect of calming you down is simply taking away the withdrawal symptoms from not having the drug for a whie. I always found coffee and nicotine very comforting, bur having given them up find caffeine in particular very stimulating.

cocaine acts as a local anesthetic by preventing the rapid influx of sodium ions into nerve axons, thus preventing the production of an action potential – the site of action is the sodium channels in the nerve membrane. (from http://www.cvm.okstate.edu/~users/aerrane/mandsagr/www/vms5422/lect09.htm ). However in the brain its hits certain neurotransmittors (dopamine or seratonine I think)

[iconoplast]

The following info may be of use:

Cocaine is a strong central nervous system stimulant that interferes with the reabsorption process of dopamine, a chemical messenger associated with pleasure and movement. Dopamine is released as part of the brain’s reward system and is involved in the high that characterizes cocaine consumption. (from http://www.nida.nih.gov/Infofax/cocaine.html)

Methamphetamine releases high levels of the neurotransmitter dopamine, which stimulates brain cells, enhancing mood and body movement. It also appears to have a neurotoxic effect, damaging brain cells that contain dopamine and serotonin, another neurotransmitter. Over time, methamphetamine appears to cause reduced levels of dopamine, which can result in symptoms like those of Parkinson’s disease, a severe movement disorder. (from http://www.nida.nih.gov/Infofax/methamphetamine.html)

It is both a stimulant and a sedative to the central nervous system. The ingestion of nicotine results in an almost immediate “kick” because it causes a discharge of epinephrine from the adrenal cortex. This stimulates the central nervous system, and other endocrine glands, which causes a sudden release of glucose. Stimulation is then followed by depression and fatigue, leading the abuser to seek more nicotine. (from http://www.nida.nih.gov/Infofax/tobacco.html)

I don’t have a good source that explains the mechanism behind the similar effects that can be caused by caffeine. scm1001 is also correct in noting that the calming effect is in part caused by alleviating the withdrawl symptoms. Overall, dopamine seems to be our main culprit. Hope that helps.