Ephedrine and Caffine in the brain

[ebola?]

I wanna know a bit more about the receptor activities of these two substances.
Caffine: What, exactly does its inhibition of the adensosine system do? Does it trigger a release of norepinepherine, or does it stimulate the sympathetic nervous system directly?
Ephedrine: Does ephedrine cause a significant release of Dopamine in addition to norepinepherine?
Ebola
np: Dead Hollywood Stars

 

[euphoria83ca]

perhaps you should log onto maybe, lets say: metacrawler or even ask jeeves. type your question there and im sure you wil get tonnes of results for it.

 

[PhreeX]

Originally posted by euphoria83ca:
perhaps you should log onto maybe, lets say: metacrawler or even ask jeeves. type your question there and im sure you wil get tonnes of results for it.
Why? He had a perfectly legit question that belongs here... sadly I dont have the time to look up the answer myself right now... but his question is right where it should be...

 

[fairnymph]

ok...
CAFFEINE: inhibits adenosine. Adenosine acts on certain presynaptic receptors to inhibit the release of the neurotransmitters, such as glutamate (an stimulating neurotransmitter), dopamine (can be either stimulating or inhibiting), and serotonin (usually inhibiting). Since caffeine INHIBITS adenosine, in the absence of this adenosine, glutamate, dopamine, and serotonin levels INCREASE. As dopamine is often converted to norepinephrine, thus there is also an increase in norepinephrine levels. Circulating adrenaline (which is also known as epinephrine) increases as well.
So, NO, caffeine does not stimulate the sympathetic nervous system directly -- rather it does so INDIRECTLY through various neurotransmitters as described above.
EPHEDRINE: this drug MIMICS norepinephrine, and secondarily, epinephrine. Thus, it DIRECTLY stimulates the sympathetic nervous system, unlike caffeine. It not know to cause significant dopamine release, AFAIK.
Hope this all helped!

 

[ebola?]

this is what i wanted...thanks.
now makes me wonder why ephedrine is more euphoric than caffine.
Ebola
np: Download

 

[zorn]

To add a couple points to babydoc's info:
Ephedrine can elicit a release of DA as well as NE, in addition to the direct agonist effects that babydoc mentioned [1]. However, it is about 20 more effective in releasing NE, so standard doses won't release a significant amount of dopamine.
Also, dopamine does NOT equal euphoria! This is a misconception. In fact, the euphoria from stimulants is probably not simply a function of DA levels. To quote the paper below, "Although it is tempting to speculate that stimulant-induced positive subjective effects in humans are mediated by a single neurotransmitter, the more likely scenario is that multiple neurochemicals aregions contribute to the subjective experience described as the 'high.'"
[1] Rothman et al. Amphetamine-Type Central Nervous System Stimulants Release Norepinephrine More Potently Than They Release Dopamine and Serotonin.
SYNAPSE 39:32–41 (2001)

 

[fairnymph]

^^^
Hey zorn...my name is fairnymph!
And yes, you are right about dopamine probably not being the cause of pleasure...funny how it is considered the "euphoric neurotransmitter" , isn't it?

 

[superbabydoc]

^^^First they spell it F A I R Y N Y M P H, now they're calling you babydoc. What an insult!
[ 19 January 2002: Message edited by: babydoc_vic ]

 

[ebola?]

Interesting.
So meth isn't just a big dopamine rush then?
Ebola
np: Radiohead

 

[ReverendLenny]

tottally unrelated, i prefer ephedrine, caffiene in high doses is a dirty high at best.