|MadSci Network: General Biology|
Hello Deshan! Thank you for your question. You asked: "What would the effects of alcohol followed by caffeine be on a Daphnia? Also, can these effects be related to the effects of coffee and alcohol on humans?" Before I answer your question, let me direct you to several previous MadSci answers that describe the effects that caffeine and alcohol have individually on Daphnia and/or the human body: www.madsci.org/posts/archives/mar99/922685827.Gb.r.html www.madsci.org/posts/archives/981603555.Cb.r.html www.madsci.org/posts/archives/may98/894059321.Me.r.html www.madsci.org/posts/archives/jul99/931925101.Zo.r.html www.madsci.org/posts/archives/feb2000/950223638.Cb.r.html Performing a MadSci search on the keywords "Ethanol," "Alcohol," and "Caffeine" will also turn up many more answers. It's a common belief that after drinking heavily, drinking a cup of coffee will "sober up" the person due to the generalized characterizations that caffeine (stimulant) will negate the effects that alcohol (depressant) has. There are several papers published which investigate whether caffeine can reverse the effects of alcohol. Here's what these researchers found: E. Nuotto M.D. and his colleagues in Finland had volunteers drink a cup of coffee after becoming intoxicated, and then tested them on various motor skills and observed their personality changes. They found no significant reversal of the effects (an antagonistic effect) of alcohol by caffeine, nor did they see an enhanced effect (a synergistic effect). Bertil Waldeck treated mice with alcohol followed by caffeine and found that alcohol and caffeine may interact to alter the metabolism of brain catecholamines, although the exact mechanisms have not yet been studied. Caffeine was not found to reverse the effects of alcohol. H. M. Franks et al. also performed a study similar to E. Nuotto using human volunteers and measuring manual dexterity, reasoning exercises, reaction times, and verbal fluency. This study also showed that caffeine did not negate the effects of alcohol on their volunteers. Mitchell et al. found that caffeine did not cancel out the effects of alcohol. He did find, however, that caffeine elimination by the body is impaired with alcohol on board, leading to higher levels of caffeine in the blood. The proposed mechanisms for this are uncertain, but Mitchell theorizes that alcohol may have some effect on cytochrome P-448, which is involved in caffeine metabolism. In summary, there is no conclusive evidence which shows that caffeine can reverse the effects of alcohol. Keep in mind that the time period between drinking alcohol and caffeine comes into play, as do their dosages. Based on the observations by the studies described above, I would guess that giving alcohol to your Daphnia will result in a drunken Daphnia. Administering caffeine afterwards should have no effect --- your Daphnia should still be under the influence of alcohol. If you are planning on testing the effects of alcohol and caffeine, please study your Daphnia with the utmost kindness and respect. I hope the above helped to answer your questions, but feel free to email me at email@example.com if you have any more questions. Sincerely, G. Monreal E. Nuotto et al.: Coffee and caffeine and alcohol effects on psychomotor function. Clin. Pharmacol. Ther 31: 68-75, 1982. Bertil Waldeck: Ethanol and caffeine: A complex interaction with respect to locomotor activity and central catecholamines. Psychopharmacologia 36: 209-220, 1974 H. M. Franks et al.: The effect of caffeine on human performance, alone and in combination with ethanol. Phychopharmacologia 45: 177-181, 1975. Mack C. Mitchell, et al.: Inhibition of caffeine elimination by short-term ethanol administration. J. Lab. Clin. Med 101: 826-833, 1983.
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