Posted by Racer on March 24, 2007, at 20:19:41
In reply to Please explain what these meds are actually doing?, posted by Sandra62 on March 24, 2007, at 17:51:24
I can't answer all of it, but here's what I do know:
Neurotransmitters are stored in vesicles inside the neurons. When an action potential triggers them, the neurotransmitters are released into the synaptic gap between neuronal cells. Once there, they communicate a message to another cell, either directly, through what are called ligand-gated ion channels, or indirectly, via G-protein coupled receptors. Serotonin, for example, has both sorts of receptors. After conveying their message, the neurotransmitter molecule is mopped up from the synapse, and transported back to the originating cell, where it's either saved for reuse, or recycled for its component proteins. The "mopper upper," if you will, is usually another molecule specifically designed to transport that particular molecule. Thus, serotonin has its transporter, and dopamine has another. The reuptake inhibitors act to stop the transporter molecules from returning the "used" neurotransmitter to the originating cell.
This leaves the neurotransmitter in the synaptic gap, where it continues to stimulate the receptor on the second cell. Eventually, that receptor says, "Enough already! I'm just going to ignore you now." That's obviously simplistic, but it's called downregulation, and it generally means that there are fewer receptors working on those cells. There are some theories that it's the downregulation of certain receptors that causes the benefits of the reuptake inhibitors. They say that SSRIs, for instance, work because the serotonin receptors get so much less sensitive that it allows more sensitivity to dopamine. No one really knows why they work, though, so it's basically educated guesses.
The reason that SSRIs have sexual side effects is beyond me. I just know they do. What worked for me, though, was taking cyproheptidine about half an hour before I wanted to -- you know. It blocks the action of the SSRIs temporarily. It's not something you'd take constantly, because that would block any action of the SSRI, and you don't want that. But for a couple of times a week, it's a good solution. It doesn't work for everyone, but it's cheap and safe, so it's probably worth a try.
As for some of the other mechanisms, like the weight gain some people get with SSRIs, no one really knows what happens, but it's likely that it involves the serotonin receptors in your digestive tract. Several receptors there regulate both bowel motility and satiety. If those receptors become less sensitive, your digestion will slow down, and the messages that you're not hungry probably won't be as clear. So they probably act both ways -- affecting your metabolism, and increasing your appetite.
I hope that's helpful.
poster:Racer
thread:743789
URL: http://www.dr-bob.org/babble/20070320/msgs/743815.html