Posted by IsoM on May 16, 2002, at 2:59:56
In reply to Re: Pressor effects and response » IsoM, posted by manowar on May 15, 2002, at 13:04:07
Hi Tim, so you're not on Provigil (or was it adrafinil) anymore? It pooped out for you? Rats, that's awful - especially when you think you've found an answer to some of your problems. Happily, I can still say I love my adrafinil.
Now about your questions, I wish Cam could answer them onstead. It's the difference between understanding what I've read & then trying to explain it to someone else; and then Cam, who knows it inside/outside & can explain it more simple & clear than me. But I'll give it a try again. Do remember, I understand it but not with the clarity he does. I hope this is an improvement, not more confusing.
1. The phenethylamine-type class of drugs include a fair amount of different ones, just as benzodiazepines are a class of drugs. Ecstasy (MDMA) belongs in this phenethylamine family. It does act on serotonin alright, but also on dopamine. So that's why I mentioned the related drugs & their effects.
2 (a). But there is a natural hormone/neurotransmitter called phenylethlamine (PEA, or the 'cuddle' hormone) that makes us feel good from its release of dopamine. But phenethylamine (& related drugs) do bind to serotonin reuptake transporters acting as an inhibitor.2 (b). Now norepinephrine (or noradrenaline) does cause a rise in heart rate & blood pressure, but so does PEA (or PEA-type drugs) too. But for reasons I don't understand, norepinephrine blocks the rise in heart rate & blood pressure that PEA causes. So, no, the effect of norepinephrine & PEA *both* have parasympathetic system effects (rise in heart rate & blood pressure among other effects) but norepineprine WILL strangely block the further effects of PEA if both are released at the same time. It's not that norepinephrine has an opposite effect than PEA, cancelling each other but only that norepinephrine "blocks" the pressor response of PEA. (Haven't a clue why & don't even know if scientists know why.)
3. I'm still not certain why sometimes it's said "pressor effect" & other times "pressor response". Just terminology perhaps? Effect is what you get & response, what you expect?
The difference between an SSRI which is to inhibit the reuptake of serotonin & that of a MAO inhibitor is the first only acts on serotonin usually (one specific monamine neurotransmitter) while MAO inhibitors block the enzyme (called monoamineoxidase) that break down monoamine neurotransmitters such as serotonin, dopamine, norepinephrine, & epinephrine thereby leaving more of these neurotransmitters in the synaptic gap. So again, yes, both MAO inhibitors & SSRIs have similar effects but just in different ways & an MAO inhibitor isn't as specific for certain neurotransmitters as an SSRI is.
poster:IsoM
thread:106073
URL: http://www.dr-bob.org/babble/20020510/msgs/106610.html