Posted by paulkid on February 26, 2013, at 20:39:43
In reply to Re: Which Drug increase dopamine the most? » JohnnyBLinux, posted by conundrum on November 12, 2009, at 21:08:44
Couple things - keep in mind that amphetamine and methamphetamine do more than just interfere with the dopamine transporter (DAT). They actually enter the cell, and force the dopamine out of the intracellular vesicles, which then causes the dopamine to get dumped out by making the dopamine transporter work in reverse. This means that you get a lot of dopamine increases with the amphetamines. This is in contrast to cocaine and methylphenidate (ritalin) which just block the transporters (yes they block the serotonin and norepi transporters too). Also, the neurons have to fire in order for dopamine to get released in the first place, so cocaine, for example, won't cause an increase unless there some activity going on. This is in contrast to amphetamine, which dumps the dopamine out no matter what. The downside of amphetamines are that intracellular dopamine is toxic (dopamine is an oxidant), so neurons can die after chronic use. This is less true with the reuptake inhibitors like cocaine. Also, animals will work harder on a progressive ratio schedule to get amphetamine injections than cocaine, but not much harder.
Second - dopamine is not reward or euphoria. It's complicated but the basic idea is that dopamine "tags" stimuli in the environment as motivationally relevant (ie salient, or "interesting"). This is how you get the increase in attention with drugs like ritalin. In some cases this can be pathological, like the induction of OCD symptoms, hypersexuality, addiction, all of these things can be characterized as excessive interest in environmental stimuli. The euphoria bit is due to activation of the endogenous opioid system (think morphine, heroin, painkillers).
Third - remember your individual differences. Ritalin makes a lot of people hyper but it calms down folks with ADHD. Some people can experiment with drugs but others become addicted. So everyone is different. Why is the big question.
poster:paulkid
thread:1038963
URL: http://www.dr-bob.org/babble/20130222/msgs/1038963.html