Posted by PhoenixGirl on January 31, 2001, at 13:37:48
In reply to Re: What does down regulation mean? » PhoenixGirl, posted by Sunnely on January 30, 2001, at 20:06:38
I don't understand how a reduction in the number of neurotransmitter receptors could help depression. Seems like it would make it worse? Or else, it seems like if you stopped the AD, and the number of receptors was still low, you would be more depressed than before you started the drug. That would make it so that you would have to stay on the drug to keep from becoming more depressed.
Hi PhoenixGirl,
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> When the rate of a neurotransmitter receptor's synthesis (production) is decreased, it is sometimes called "down regulation" or desentization. During this process, the number of a neurotransmitter receptor is reduced. This process takes days. This is postulated to be the mechanism involved in the antidepressant drugs' action. For example, when Prozac (an SSRI) is taken, it inhibits the reuptake of serotonin (neurotransmitter) to the storage vesicle, thereby increasing serotonin's availability in the synapse. After several days (2-3 weeks) of serotonin reuptake inhibition, the serotonin receptors involved become "down regulated" (decreased in number). This time period also coincides to the onset of antidepressant action (lag time).
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> On the other hand, when the rate of a neurotransmitter receptor synthesis is increased, it is sometimes called "up regulation." Too much receptor synthesis (production) may not only increase the sensitivity of neurotransmission but may also produce a disease. Exactly this is suspected to be the case for the condition known as tardive dyskinesia (TD), which is apparently caused when drugs that block dopamine receptors cause abnormal changes in the number or sensitivity of dopamine receptors.
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> > I've read that ADs can "down regulate" neurotransmitter receptors. Desipramine, for example, is said to "down regulate" 5H2 serotonin receptors. What does that mean, and is it permanent? What effect does it have on people?
poster:PhoenixGirl
thread:52975
URL: http://www.dr-bob.org/babble/20010131/msgs/53040.html