Gayle,

You remember correctly (although I don't have a concentration at hand).
Also, lidocaine can be used to relax the vessel walls and get better
penetration into the arterioles and capallaries.

Phil

>If I remember correctly, heparin (in perfusion fluid?) is used to prevent
>clotting problems.  Linda Jenkins has done this, plus some others, any
>comments
>
>
>
>>Date: Wed, 29 Mar 2000 09:17:16 -0500
>>From: Pam Marcum <pmarcum@polysciences.com>
>>Subject: RE: perfusion confusion
>>To: Roger Moretz <stamptrain@yahoo.com>, Karen Larison
>>    <larisonk@uoneuro.uoregon.edu>, HistoNet@Pathology.swmed.edu
>>
>>We did a large number of perfusions of rats and never used cold fixative.
>>It was room temperature.  The only person I knew who tried was a grad
>>student and the perfusion did not go well.  He tried it several times and it
>>just never worked well.  The brains did not fix well and we had swelling and
>>burst vasculature due to the cold temperature.  It caused clotting and
>>problems with processing and cutting.  Pam Marcum
>>
>>-----Original Message-----
>>From: Roger Moretz [mailto:stamptrain@yahoo.com]
>>Sent: Wednesday, March 29, 2000 8:22 AM
>>To: Karen Larison; HistoNet@Pathology.swmed.edu
>>Subject: Re: perfusion confusion
>>
>>
>>Karen:
>>I don't have any references to the use of cold
>>fixatives for this purpose, but I can't believe that
>>perfusion with cold fixative would work that well.
>>The vasculature will contract upon the initial
>>exposure to the cold unless a relaxant has been used,
>>and even then I'm not sure that this will obviate that
>>problem.  I have always used fixative that is at least
>>at room temp, and in some instances have run the
>>perfusion tubing through a warm water
>>bath--particularly since we were looking at the blood
>>brain barrier.
>>
>>Roger Moretz
>>Dept of Toxicology
>>Boehringer Ingelheim Pharmaceuticals, Inc.
>>
>>
>>--- Karen Larison <larisonk@uoneuro.uoregon.edu>
>>wrote:
>>> Histonetters,
>>>
>>> One of the labs here is doing in situ hybridzation
>>> on developing rat brains.  They
>>> have been using ice-cold perfusate on these rats as
>>> they believe that this prevents
>>> endogenous RNAses from acting.  I have a hard time
>>> believing this, particularly in
>>> light of the evidence that paraformaldehyde fixation
>>> effectively neutralizes
>>> endogenous RNAses (J Neurosci Meth 85 (1998) pp
>>> 129-139).  If this is true, why would
>>> you want to slow the fixation rate by perfusing with
>>> ice-cold perfusates?
>>>
>>> If anyone knows of any references that would clarify
>>> this issue or if anyone has had
>>> some practical experience on perfusion and in situ
>>> techniques, I'd appreciate hearing
>>> from you.
>>>
>>> Thanks for your kind advice.
>>>
>>> Karen in Oregon
>>>
>>>
>>>
>>
>>__________________________________________________
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>>
>>
>>
>Gayle Callis
>Veterinary Molecular Biology
>Montana State University
>Bozeman MT 59717-3610
>406 994-4705
>406 994-4303

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