Why Be Awake? (Re: A Theory of Sleep)

John H. John at faraway.com.au
Thu Oct 11 09:09:37 EST 2001


"Statik" <czero93 at hotmail.com> wrote in message
news:c480423c.0110081456.7e7d98df at posting.google.com...
> "yan king yin" <y.k.y@(no spam please)lycos.com> wrote in message
news:<9pnkq8$jjs14 at imsp212.netvigator.com>...
> > The conclusion seems to be that sleep has some special function. It
> > could be recuperative, such as replenishing neurotransmitter stores.
> >
>
> First off, I should mention that I am new to this group.  I am a
> biology student at University of Wisconsin Whitewater. So I suppose
> you can regard this as 'Hi'.
>
> One would first jump to the conclusion that sleep has to do with
> neurotransmitter replenishment.  However, observation seems to
> indicate that we replenish neurotransmitters during waking hours just
> fine.

We can replenish some neurotransmitters, but the problem may be with respect
to neuro modulators.

Take the example of a person using MDMA which causes mass
> release of seretonin.  When the effect of the drug wears off, they
> will often take another dose but find that it is ineffective.  That is
> because all of their serotonin has been reabsorbed into the neuron
> after release and is awaiting to be brought back into the vesicles
> (which is the part of reuptake that takes most of the time).  This can
> happen while awake, as sometimes people will take and feel the effects
> of the drug more than once during a waking period.  However it is a
> safe guess that this process is far more active in the sleeping brain,
> which accounts for hallucinogenic effects of extreme sleep
> deprivation.

MDMA has been demonstrated to cause extensive damage to serotonin cells. One
researcher has claimed that 100 uses of the drug is sufficient to cause
damage and increasing amounts of research point towards PERMANENTLY depleted
serotonin resulting in mood and cognitive functions, will will probably only
worsen with age. (Caveat: I have one study on rats that showed substantial
serotonin recovery one year after loss from MDMA. There may be hope yet for

all those who thought this was another safe drug but I doubt it.) Not sure
of the process that gives rise to this, can only speculate that as serotonin
metabolism generates super anions, and this together with nitric oxide,
released under some types of glutamate receptor activation(assuming high
levels of glu in MDMA and LSD), can give rise to peroxynitrate , which
nitrates tyrosine H and and generally does a lot of damage to cells.


After MDMA a person will feel 'washed out' for a few days, no matter how
much they sleep. I suspect the serotonin is not waiting to be reabsorbed
into vesicles, but has been lost forever, metabolised and gone. If it were
just a matter of transport back to vesicles, then a day should be ample.
MDMA probably
causes a low level but nonetheless deleterious inflammatory reaction. The
subsequent release of cytokines like il1 and tnf will induce fatigue (hence
why you feel tired when you get the flu and other viruses) and have been
demonstrated to inhibit cerebral metabolism; not to mention causing cell
death.


> However, I take a different stance on sleep.  This falls more in the
> realm of psychology than biology and focuses on dreaming.  Oftentimes
> people recall certain events of the previous day appearing in various
> mutations throughout a dream.  Could it be possible that it has
> something to do with editing long-term memory?  This also goes along
> with what someone had mentioned about becoming mentally slower with
> lack of sleep.  Perhaps the brain is becoming overtaxed with all the
> data that is waiting to be edited and compressed during the dream
> cycle.  Of course the mental slowness could be accounted for by lack
> of seretonin.

If dreaming is simply about long term editing etc, then one would expect
those who are learning a great deal to be dreaming a great deal more than
others and children should dream every sleeping minute. It appears however
that dreaming increases during anxiety, I don't know of any studies
indicating increased dreaming during intense learning but if anyone know of
the same please tell. Is there a relationship between IQ and sleep
requirements? I have heard that some gifted children require less sleep than
others but I don't think the trend is consistent across the board. Remember,
only some gifted children, not all.

Long term memory is one thing amongst many that can be affected. Tests seem
to reveal a range of cognitive deficits, many of these having nothing to do
with processing information for long term purposes. Recently read an
interesting abstract about how a one hour nap helped to prevent performance
fatigue in some psych test or the other, and that this effect correlated
with the amount of SWS during the nap. Also the fatigue effect was at the
retina\primary visual (ie, not related to some generalised fatigue), as if
the retinal cells were only good for so much intense sustained activity,
keeping in mind that most of the time we are operating at a fairly sub
optimal level, but in a test it tends to be 'all hands on deck', so any
metabolic deficit may be more noticeable because something about this visual
test clearly had the capacity to fatigue the primary visual cortex in
testings sessions throughout a single day.

On this angle, I remember an older study indicating that while mild stress
can improve cognitive performance for a period, other recent material that I
cannot reference suggests that in humans at least this effect is good for
about six hours. Nor epinephrine can improve cognitive performance, but
we're talking about hours here, it seems that after a time a deficit sets
in, as if the brain can't sustain that pace for too long.

I would exercise some caution in adopting the assumption that our brains
can -easily- replenish the Neuro T levels throughout the day. To be
balanced, my hobby horse is that human brains are, from an evolutionary
perspective(got any other?), working overtime. Not just bigger brains, but
much harder working brains, even before school was invented. Glutamate,
Gaba, Ach may always be readily to hand, but dopamine and serotonin,
produced by not that many cells, but fluctuate through a number of processes
and this probably has implications for our cognitive integrity at the end of
the day. Can't think straight anymore, better sleep ... .

As to lack of sleep generally, what about circadian rhythms? Think about jet
lag, no loss of sleep
there but recent research points to low level cognitive deficits in those
who experience a lot of jet lag. What I would like to know is if SWS
initiates melatonin production or is melatonin production during sleeping
hours simply a function of just sleeping, not SWS specifically.



John H.







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