N&PD Moderators: Skorpio | someguyontheinternet
Anyone know of any drugs (they don't even need to cross the BBB, just any sort of medically useful molecule) that is hypervalent?
Well the problem with DAT is how freaking similar it is to NET
in the PFC there aren't even any DAT transporters; NET is responsible for DA uptake there.
Not to mention how DAT is pretty much identical to NET downstream
I don't think that I understand this point. At what point in signaling is the function of DA transporters similar to that of NE transporters? If we're talking about efflux rather than mere transport of the endogenous ligand, does this trend hold?
ebola
EA said:Well to my understanding most of the selectivity is conferred by the brain simply having more NE stores and NET transporters, so to reach half maximal activity you need far lower releasing agent concentrations for NE than DA. This is from my pharmacology prof, so it might not follow current research as far as it was the leading theory some years ago.
What I meant for that was catecholamines all share very similar transport/synthesis pathways, so its very difficult to cause selective DA efflux without NE efflux.
Though, without a double there are agents more selective for DA vs NE than others.
So this is during a coffee break before a lab so bear with:Ah. Right. But if you look at the binding affinities themselves, we have agents where the ki for DAT is 2-3 orders of magnitude larger than the ki for NET. Even in an environment where NET and DAT densities are similar, these agents would remain selective for NET. So my question is, why don't we have ligands where the pattern of affinities and efficacies is reversed?
Gotcha. Yes, here I concur, given (as you note) the role of DA uptake by NET in the pfc and downstream metabolism of DA to NE. However, there are numerous downstream processes where selective efflux at DAT would have vastly different consequences than selective efflux at NET.
However, we don't yet have agents that are selective for DA per se; every known DA releaser actually has a stronger effect at NE.
ebola
EA said:Well most of the problem comes from the fact that using traditional SAR, as things become more selective for DAT vs NET it also starts to bind to other things, for example meth vs regular amp. DAT just loves those oily mofo's.
But what I was getting at is the PKC mediated releasing action really isn't that different for NE vs DA, so using the traditional amphetamine MOA isn't ever really going to give you a greater DA/NE ratio.
My mistake.
Aha! Another piece of the puzzle that I didn't understand. So amphetamine-like efflux is achieved by the exogenous ligand inducing PKC to phosphorylate the transporter (by binding to PKC, changing its conformational form?). Okay, so if this mechanism is fundamentally similar whether we're talking about DAT or NET, why do releasers have any selectivity at all? Are there different isoforms of PKC present proximate to different transporters?
ebola
How much exactly does your heart rate increase on Meth/Amps?
one of the samples was independently tested.
the more potent one was the one that was independently verified. the less potent one is the one with the vendor crying up and down in the thread that his stuff must be 99.9% pure.
i think i've heard enough lol, thanks guys
the stuff that was third party tested was originally sold as JTE-907 btw. the trip reports made a lot more sense once the lab results came back. glad i stayed away from that one until it got lab confirmed.... UR-144 did end up being pretty nice though.