The HCl salt should go into solution fine with minimal correction for formula weight. Get it from Sigma. The bitartrate salt FW is huge, so you will have to make a larger correction when you weigh it out. Make sure that you include abscorbic acid (100 uM) to the medium prevent NE oxidation. I really don't understand why you need such a large concentration of NE- the Kd for the alpha adrenergic receptor is around 1 nM.

Bitartrate or HCl salt should be fine. Should have no problem solubulizing. As James Carr mentions, need to correct for the formula weight and add ascorbic acid to prevent oxidation.

If you are interested in mimicking the effects of the natural transmitter/hormone, then you must choose the naturally-occurring stereoisomer, which is the - (minus) or L form. You might get away with generating biological effects using the (probably cheaper) DL racemic mixture, but I'd suggest you avoid introducing this complication.

Thanks so much for all the information. I will get the NE-HCl (L form) from sigma and dilute in H2O. I was wondering if any of you might be able to answer some other basic questions.

Should the dilutions be made in the dark (I know dopamine is light sensitive)? Should they be made fresh for each use or can I make up a stock and store it in aliquots at -80°C?

In terms of breakdown, how rapidly does NE break down in culture media or water? Is it similar to dopamine? Does it get bound by serum proteins as well? I ask because ascorbic acid itself modulates some macrophage activities so I would rather not use it unless necessary.

I am interested in the high concentration because of the way I make dilutions, so I hope to use NE in the low micromolar - high nanomolar range ... but different studies have used a variety of concentrations of NE on macrophages, so I wanted to be able to use a wide range of concentrations.

Have always used it with ascorbic acid. I would aliquot and keep in deep freezer and thaw the aliquots as needed. Activity remains for at least a few weeks (the assay measure here was it's pressor activity in anesthetized preps). Wrapping the bottle with foil or use amber colored containers will attenuate the photodegaradtion.

NE is probably a bit more sensitive to oxidation/light etc than dopamine, but if kept acidic in stock it shouldn't be a problem using normal lab lighting in dilutions - I never bothered with diluting in the dark. Stocks should be fine frozen as aliquots - just use the diluted active solutions quickly. You may find that ascorbate in stock is low enough following dilution not to matter in your experiments, alternatively use bisulphite as an antioxidant (if its good enough for sauvignon blanc it may be ok for macrophages!) in your stocks. Good luck!

It is also possible to use glutathione to reduce breakdown, if that is a better alternative for you than ascorbic acid. Unlike dopamine NE does not fare that well in acidic solutions. Frozen aliquots in water should be OK for several months.

We use +/- bitartrate salt and solublize in H2O to 10mM without ascorbate. This is done in the light and we store at 4 deg for several weeks without a noticeable decrease in effectiveness. If it starts to turn yellow, it is oxidizing. If you're doing a concentration response you can certainly make up a stock and use it for a couple of days.

As far as in culture, it will likely oxidize much faster at higher temperatures. If you're doing an experiment on the order of minutes to maybe an hour or so, it should be OK. If you know the specific receptor type on the macrophages, it would be safer to use a more specific agonist that won't be oxidized, transported or hit multiple receptors.

Follow Gavin's adviceNA/NE is readily oxidized, so be aware of heavy metals that will catalize the oxidation, if possible use EDTA (or EGTA) to neutralize this problem.