Re: catecholamine histofluor

From:"J. A. Kiernan"

Rachel Munshower wrote:
>   Can anybody help me with getting some info on Catecholamine
> histofluorescence?  We want to be able to see the sympathetic 
> innervation of the kidney.  
This is a classical histochemical method developed in the early
1960s, based on the reaction of formaldehyde gas with
freeze-dried blocks of tissue. Later developments allowed the
use of vibratome and even cryostat sections. Several variants
were developed, with the best and most sensitive being published
about 1979. At about that time, extremely reliable antisera to
tyrosine hydroxylase (TH) became commercially available, and the
specific staining of catacholamines became technically simpler,
probably more sensitive, and applicable to conventionally
prepared sections. 

Having used both types of method, I recommend TH histochemistry
for any serious study of noradrenergic sympathetic innervation.
Formaldehyde-induced fluorescence can give great results, and
is a splendid practical exercise for students of Histochemistry,
but I'd be surprised if it's used at all in routine or research
work nowadays. If I'm wrong, please let me know, and why; I'd
be delighted to hear if these methods still have their uses. 

> Does the histofluorescence diminish severely with time?

It keeps for days or a few weeks. The fluorophore is removed
by exposure to water or alcohol (but not by wax or Entellan).
If this reply has not deterred you from trying one of the
"catecholamine histofluorescence" methods, ask again by way
of Histonet and I'll be happy to provide some references to 
the literature. The best technique will be determined by the
requirements of your investigation. What question(s)are you 
trying to answer? Do other facets of the research limit the
way the specimens can be prepared? What section thickness will
display the sympathetic fibres in such a way as to provide
answers to your questions? All these considerations matter,
whether you use a classical-type fluorescence method or
John Kiernan
London, Canada

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