Posted by sregan on May 11, 2010, at 17:13:21
In reply to Adenosine receptors, caffeine, and dopamine, posted by SLS on February 9, 2009, at 7:16:51
Scott,
I have a balance issue with adenosine I believe. I think I have way too much running through my system. I'm definitely dopamine starved.
I've tried caffeine and in the short term it does fine but more than a couple of weeks I find my adrenals depleted.
I've read that Vinpocetine inhibits adenosine uptake. Would you know something that might increase it's uptake?
> Adenosine is a nucleoside substance that the brain uses to inhibit and "quiet" hyperexcitable cells. Adenosine is considered to be a gliotransmitter, as it is secreted by astrocytes, a type of glial cell, and not neurons.
>
> One of the primary cites of adenosine receptors are glutamatergic neuron terminals. It gets somewhat complicated in that their are several types of receptors, but for the sake of understanding the pathway, A1 adenosine receptors are the target of the inhibitory message.
>
> Normally, adenosine release from astrocytes promotes sleep-pressure - the desire to sleep. By inhibiting glutamate neurotransmission, it also inhibits the release of dopamine in the nucleus accumbens, one of the major reward centers of the brain.
>
> Caffeine is a substance which antagonizes (blocks) adenosine receptors. It does just the opposite of adenosine. It allows for an increase in glutamate (disinhibition), an increase in dopamine and reward, and wakefulness.
>
> Some of the other contributors to the modulation of glutamatergic neurotransmission are GABA neurons the main inhibitory neurons and receptors in the brain, which are now known to express adenosine A2a receptors, which work to oppose A1 receptors. Caffeine would increase GABA transmission and produce a calming effect. This might be why some people find coffee calming or soothing.
>
> I am just beginning to understand this stuff, so my explanation is far from concise. However, I thought it was important to demonstrate the events that lead up to caffeine producing an increased release of dopamine in the striatum.
>
> Caffeine is pretty cool stuff. I've been using it for 25 years as a palliative drug to reduce the vegetative aspects of depression.
>
>
> - Scott
>
poster:sregan
thread:879068
URL: http://www.dr-bob.org/babble/neuro/20100223/msgs/947134.html