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標 題Re: [請問]咖啡因上癮和訊息傳遞之間的關係?
發信站KKCITY (Tue Jun 6 06:49:08 2006)
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※ 引述《colulu ( )》之銘言:
> 如題
> 咖啡因在人體的訊息傳遞pathway中是不是有明確的途徑?
> 小弟上網找了很久 都沒有比較完善的資料
> 但是基本的神經傳遞理論先前有建立好
> 只是不太曉得咖啡因上癮和神經、訊息傳遞上的明確關係
> 希望各位大得提供見解 感恩感恩^^
除了下面說的pathway外, 咖啡因可能也抑制mTOR pathway (in vitro),
另外印象中記得有些酵素需要咖啡因當cofactor.
http://www.STKE.org
Sci. STKE, Vol. 2002, Issue 146, pp. tw303, 20 August 2002.
[DOI: 10.1126/stke.2002.146.tw303]
NEUROBEHAVIOR:
Coffee, Caffeine, and DARPP-32
Caffeine is a well-known psychostimulant that increases motor activity by
inhibiting the action of the neuromodulator adenosine. By binding to
adenosine receptors (A1 and A2A) present in inhibitory neurons in the brain,
caffeine prevents activated A2A receptors from initiating a signaling pathway
that triggers cAMP production and protein kinase A (PKA) activation. Lindskog
et al. report the behavioral effects of caffeine are no longer observed in
mice lacking the cytosolic protein DARPP-32. This is because caffeine
increases the phosphorylation of DARPP-32 on a specific threonine residue. By
blocking the cAMP-PKA pathway, caffeine decreases the action of the protein
phosphatase 2A on DARPP-32. Phosphorylated DARPP-32 can then further inhibit
PKA activity, amplifying the shutdown of the cAMP-PKA pathway. The effect
likely includes a lower level of phosphorylated target proteins of PKA that
regulate nerve activity.
M. Lindskog, P. Svenningsson, L. Pozzi, Y. Kim, A. A. Fienberg, J. A. Bibb B.
B. Fredholm, A. C. Nairn, P. Greengard, G. Fisone, Involvement of DARPP-32
phosphorylation in the stimulant action of caffeine. Nature 418, 774-778
(2002).
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