Agreed . One could use tinctorial methods in confirming abscence or even
reduced numbers of Ache +ve ganglia/fibres but as you state....difficult
.Immuno against Ache itself or NCAM or NF for eg  will unequivocally
demonstrate these cells/processes. However, I put this Q to the great Brian
Lake at Grt Ormond St Childrens Hospital UK a few years ago and he replied ,
if it aint broke, don't fix it! ( using IHC as an alternative to detection
of enzyme activity)
I have used IHC in Pwax trials and it looked good...( thinking of the hassle
of frozen sectioning)but I'm not an expert. Then I left clinical labs.
Carl
Carl Hobbs
Laboratory Manager
Molecular Neurobiology Group
MRC Centre For Developmental Neurobiology
New Hunts House
Guys Campus
kings College London
SE1 1UL
020 7848 6810/fax 6816