Pharmacology
Dexedrine is the brand name for dextroamphetamine, a powerful stimulant medication. The main effect of dextroamphetamine, according to an article in the journal "Psychopharmacology," is mediated by the effects that it has on certain chemicals in the brain known as neurotransmitters. Neurotransmitters are chemical messengers that neurons use to communicate with each other. The neurotransmitters are pumped into small junctions between neurons called synapses. The longer a neurotransmitter is present in the junction, the more effect it has. Dextroamphetamine slows the rate at which two different neurotransmitters, dopamine and norepinephrine, are pumped out of the synapse.
Mechanism for ADHD
One use of dextroamphetamine, according to MedlinePlus, is in the treatment of attention-deficit hyperactive disorder (ADHD). Although the exact cause of ADHD is not completely understood, researchers have noted that patients with this disorder have lower levels of dopamine in their brain. The neurotransmitter is involved in regulating attention, focus and motivation. Dopamine is thought to be important for "gatekeeper" neurons which are needed to properly prioritize actions, thoughts and impulses. Stimulant medications like dextroamphetamine are able to increase the effects of naturally occurring dopamine in the brain and can help correct the deficiencies in the brains of ADHD patients.
Narcolepsy
The other neurotransmitter that dextroamphetamine affects, norepinephrine, is important for the treatment of narcolepsy. Patients with narcoplepsy fall asleep uncontrollably, possibly due to reduced amounts of a protein called hypocretin. Norepinephrine is also known as adrenaline. Stimulant medications such as dextroamphetamine increase norepinephrine signaling in the brain, which increases alertness and helps keep patients from falling asleep.
