ScienceDaily: New Theory May Explain Ritalin Action In Hyperactivity
The researchers found evidence that Ritalin works by affecting levels of the brain chemical serotonin, which helps regulate mood and inhibit aggression and impulsive behavior. Current theory holds, however, that Ritalin calms people with ADHD by affecting the level of the brain chemical dopamine, whose actions include regulation of activity and locomotion. Both dopamine and serotonin are neurotransmitters, chemicals which are launched by neurons, or brain nerve cells, to trigger nerve impulse in neighboring neurons.
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Based on this finding, Caron and his colleagues believe that ADHD-like symptoms in the knockout mice are caused as much by having too little serotonin in the brain as by having too much dopamine, and that restoring a balance between the two brain chemicals is the key to controlling hyperactive behavior.
"We've always thought of ADHD as a function of too much activity in the brain, and it is," said Gainetdinov. "But it also appears to be a function of the brain's failure to inhibit impulses and thoughts that we all have, but which we are typically able to control. Ritalin helped control behavior in these mice by boosting serotonin's calming effects on dopamine, rather than by acting directly on dopamine, as had long been assumed.
"Our findings provide the tantalizing possibility that hyperactivity in ADHD patients might be controlled through precise targeting of serotonin receptors, or even by supplementing serotonin precursors, such as dietary tryptophan" Gainetdinov said. "In other words, giving them selective serotonin drugs could have the same effect, or even better, than Ritalin or Dexedrine."
The researchers found evidence that Ritalin works by affecting levels of the brain chemical serotonin, which helps regulate mood and inhibit aggression and impulsive behavior. Current theory holds, however, that Ritalin calms people with ADHD by affecting the level of the brain chemical dopamine, whose actions include regulation of activity and locomotion. Both dopamine and serotonin are neurotransmitters, chemicals which are launched by neurons, or brain nerve cells, to trigger nerve impulse in neighboring neurons.
[...]
Based on this finding, Caron and his colleagues believe that ADHD-like symptoms in the knockout mice are caused as much by having too little serotonin in the brain as by having too much dopamine, and that restoring a balance between the two brain chemicals is the key to controlling hyperactive behavior.
"We've always thought of ADHD as a function of too much activity in the brain, and it is," said Gainetdinov. "But it also appears to be a function of the brain's failure to inhibit impulses and thoughts that we all have, but which we are typically able to control. Ritalin helped control behavior in these mice by boosting serotonin's calming effects on dopamine, rather than by acting directly on dopamine, as had long been assumed.
"Our findings provide the tantalizing possibility that hyperactivity in ADHD patients might be controlled through precise targeting of serotonin receptors, or even by supplementing serotonin precursors, such as dietary tryptophan" Gainetdinov said. "In other words, giving them selective serotonin drugs could have the same effect, or even better, than Ritalin or Dexedrine."
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