X-Message-Number: 4665
From: 
Date: Mon, 24 Jul 1995 20:51:20 -0400
Subject: SCI. CRYONICS rabbit brain

I'll have to forego the indicated long response to Mike Darwin's #4661, even
though I have strong disagreements with several items; I just can't take time
now. Maybe later.

We now have Dr. Yuri Pichugin's  report on the bioelectric activity in rabbit
brain pieces, although some of the graphs are still to come;  we expect to
publish all of it in the September issue of THE IMMORTALIST. 

Very briefly, my impression of the import of the results and discussion is as
follows. This is being sent to Dr. Pichugin for possible correction.

1. Bioelectric activity, spontaneous and evoked, was shown by glycerolized
specimens even after freezing to liquid nitrogen temperature, whereas the
non-glycerolized specimens did not show BEA even after cooling to -10 C.

2. The main BEA of the rabbit cortical slices was recorded at frequencies 0.2
- 1.0 Hz. This range relates to functional activity including that of
noradrenaline neurons and synapse apparatus. Evoked potentials indicate
possible activity of neurons and synapse apparatus not expressed in normal
spontaneous activity. 

3. Qualitatively, the results indicate that the majority of the neurons in
the slices are in some degree functional, with integrated activity, and that
the majority of synapse contacts are preserved.

4. Results also indicate that at least the neuron membranes and their
processes are intact, and cell systems that ensure membrane potential and
action potential work to some degree. Noradrenaline and external electrical
impulses induce action potential, which means that the system of
neuromediators is functional. 

5. Quantitative evaluation presents problems in such functions as
respiration, nutrition, general exchange of substances etc. It is difficult
to examine the functions of glial cells, which are less cryoresistant than
neurons. Many questions could be answered with better culture conditions.
Reanimated slices can now be preserved 2-3 hours, but causes of damage and
eventual death remain to be determined.

6. This work was peliminary to study with fresh cat heads and probably
post-operational pieces of human brain tissue.

Our thanks to Drs. Pichugin, Marchenko, and Shilo, and we hope the follow-ups
can proceed expeditiously. 

Robert Ettinger
Cryonics Institute
Immortalist Society


Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=4665