On Thu, 12 Oct 2000, Gayle Brosnan-Watters wrote:

> Can anyone tell me if it is okay to perfuse mice with a perfusate containing
> glutaraldehyde when I am going to do the Tago technique for cholinesterase
> staining?  

Yes.

The original paper (Tago, Kimura & Maeda 1986 J Histochem Cytochem
34: 1431-1438) says fix for 1 to 4 days in 1 to 4% formaldehyde, 
with or without 0.5 to 2% glutaraldehyde. Alternatively, fix in 4%
formaldehyde and 0.2% picric acid in 0.1M phosphate buffer, pH 7.4.

The principle of this method is that you use a 100X diluted medium
of the Karnovsky-Roots type. The reaction product (copper ferrocyanide)
has a peroxidase-like activity, and is amplified by a DAB-H2O2
incubation. It is sometimes necessary to inhibit endogenous peroxidase
activity, especially in unfixed cryostat sections, by putting them
in 0.1% H2O2 for 30 minutes before starting the AChE incubation.
 

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1