recently i was reading a bit about these x-APB compounds on wikipedia and found this:
I always was under the impression that these drugs were monoamine releasers like MDMA and the like. are the wikipedia articles incorrect or not?
"There is now an abundance of evidence, both experimental and clinical, that MDMA and the other ring-substituted amphetamine derivatives act by increasing the net release of the monoamine neurotransmitters (serotonin, noradrenaline and, to a smaller extent, dopamine) from their respective axon terminals.3,26,27 MDMA does not act by directly releasing serotonin but, rather, by binding to, and thus blocking, the transporter involved in its reuptake.3,28,29"
http://www.cmaj.ca/content/165/7/917.full
Some background information: There are a bunch of monoamine neurotransmitters in humans. Some are tryptamines, like serotonin and melatonin. Others are catecholamines, like dopamine, norepinephrine, and epinephrine. There are also histamines and other trace amines.
The abbreviations NET, DAT, and SERT refer to different monamine transporters: norepinephrine transporters, dopamine transporters, and serotonin transporters, respectively.
"Ki is the symbol for the dissociation constant of an inhibitor; in enzyme kinetics, Kii reflects the values of Ki that affect the intercept of a double-reciprocal plot, whereas Kis reflects the values of Ki that affect the slope of the same plot." (
http://www.biology-online.org/dictionary/Ki "The inhibitor constant Ki is the concentration of inhibitor which is required to decrease the maximal rate of the reaction to half of the uninhibited value, in the presence of a low substrate concentration. Therefore, the lower the Ki the lower the concentration of inhibitor needed to lower the rate."
http://dwb4.unl.edu/Chem/CHEM869K/C...S/DEPT/biochemistry/kinetics/HTML/PAGE21.HTML
"In pharmacology, an "agonist" is a drug that has an affinity for and stimulates physiologic activity at cell receptors normally stimulated by naturally occurring substances."
http://medical-dictionary.thefreedictionary.com/Agonists
However... "New findings that broaden the conventional definition of pharmacology demonstrate that ligands can concurrently behave as agonist and antagonists at the same receptor, depending on effector pathways or tissue type. Terms that describe this phenomenon are "functional selectivity", "protean agonism",[4][5] or selective receptor modulators.[6]"
http://en.wikipedia.org/wiki/Agonist Something interesting to keep in mind.
I have read all over the place that 6-APB is a serotonin releasing agent. (That's why it's nice to take 5-HTP afterward, to help restore depleted reserves.) My own experiences with 6-APB support this.
So, yep, 6-APB is both a monoamine reuptake inhibitor and thought to be a releasing agent of 5-HT (serotonin), DA (dopamine), and NE (norepinephrine).
I'm such a novice biochemist, but I want to learn! I'm confused about how Ki is measured. Can anyone help me understand this better?