Monday, March 25, 2013
Prompt 3: Tolerance and Big Idea 3
On page 178, Moalem explains physiological tolerance. Physiological tolerance is a form of gene expression in that the presence of a drug, medicinal or otherwise, will cause the promotion or suppression of the specific genes that help process the drug. This relates to Big idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes. When your body receives a substance like alcohol, it will promote the production of the enzyme alcohol dehydrogenase to help break down the alcohol. Drinking a lot will keep the production of that enzyme high, but when you stop drinking, your body will slow down production. Tolerance can be problematic, as when a patient is taking a prescribed medication, but the effects are no longer potent enough to be useful, or if a drug user is become tolerant and must take more of a drug to get the same feeling, which can lead to overdose.
Explain the relation between tolerance and metabolism, like in the example of high alcohol dehydrogenase levels leading to faster transformation of ethanol to acetaldehyde. Also, how is tolerance related to dependency?
What happens to your body when you become tolerant to alcohol, cocaine, or oxycodone? Why do drugs such as LSD and marijuana not cause tolerance?
(Posted by Tina Tian, ttian4@students.d125.org)
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When a person becomes tolerant to alcohol or a drug, they can process more of that substance without being affected by the negative side affects. When a person is exposed to more of the alcohol or drug their body begins to manufacture more enzymes to break down the toxins. The body increases the rate of metabolism in order to detoxify the body and anticipate more toxins entering the body. Therefore, there is a direct relationship between tolerance and metabolism.
ReplyDeleteWhen a person becomes tolerant to some substance like alcohol, they are producing more enzymes to hydrolyze the toxin, like alcohol dehydrogenase (Moalem 178). The alcohol dehydrogenase affects the severity of some of the negative side affects of alcohol, including drunkenness. The person needs more of the same toxin in order to feel drunk and the body is still producing a lot of alcohol dehydrogenase. The high levels of alcohol in the body are anticipated when the body is used to more toxins and producing so much alcohol dehydrogenase. In a tolerant person, they experience different side affects when there is no alcohol present in their system. This means they are dependent on the toxin to feel “normal”. The body has adapted to the presence of alcohol and has amped up metabolism, promoting genes to deal with the alcohol (Moalem 178).
The same happens with other substances besides alcohol, like cocaine or oxycodone. These drugs are metabolized by certain enzymes: CYP450 and cholinesterases, respectively. In the cases of drugs like LSD and marijuana, the body can still become tolerant to the drug but the side effects of withdrawal in someone who is tolerant are much less severe than with other typical addictive drugs.
Sources:
Axelrod, J., Brady, R. O., Witkop, B., & Evarts, E. V. (n.d.). The distribution and metabolism of lysergic acid diethylamide. (1957). Annals of The New York Academy of Sciences, 66, 435-444.
Katelyn Noronha, knoronh4@students.d125.org