Retinoic Acid

One method to differentiate neuroblastoma cells is to treat the cells with
retinoic acid (RA). I have seen two protocols; one uses RA in ethanol, the
other RA in DMSO. Both are made up at a stock of 10-2M and then diluted 1
in 1000 when treating the cells. Which method is preferable, or is there
any particular difference? Furthermore, I believe that RA is
light-sensitive and the solution is unstable. Would anybody have
suggestions for storage conditions, and is is sensitive to repeated
freeze-thaw cycles?

Thanks,
Kieran Breen


Kieran Breen, Dept. of Pharmacology,                  
University of Dundee,                   
Ninewells Hospital & Medical School,    
Dundee DD1 9SY,Scotland, U.K.                                              
               
k.c.breen at dundee.ac.uk