Re: What actually occurs inside your body during the Adrenalin rush.

Hi Katie. 
First, read the following 2 articles.  The source of the articles is 
mentioned at the end of each.  Then try the links.

ARTICLE 1

The adrenal medulla consists of masses of neurons that are part of the 
sympathetic branch of the
autonomic nervous system. Instead of releasing their neurotransmitters at a 
synapse, these neurons release
them into the blood. Thus, although part of the nervous system, the adrenal 
medulla functions as an
endocrine gland.

The adrenal medulla releases: 

     adrenaline (also called epinephrine) and 
     noradrenaline (also called norepinephrine)

Both are derived from the amino acid tyrosine.

Release of adrenaline and noradrenaline is triggered by nervous stimulation 
in response to physical or
mental stress. The hormones bind to adrenergic receptors - transmembrane 
proteins in the plasma
membrane of many cell types.

Some of the effects are: 

     increase in the rate and strength of the heartbeat resulting in 
increased blood pressure 
     blood shunted from the skin and viscera to the skeletal muscles, 
coronary arteries, liver, and brain 
     rise in blood sugar 
     increased metabolic rate 
     bronchi dilate 
     pupils dilate 
     hair stands on end ("gooseflesh" in humans) 
     clotting time of the blood is reduced 
     increased ACTH secretion from the anterior lobe of the pituitary. 

All of these effects prepare the body to take immediate and vigorous 
action. 

source: http://www.mmra.org/~jkimball/BiologyPages/A/Adrenals.html#adrenaline


ARTICLE 2------------------------------------------------------------------


Cornell University 
18-Apr-98 

                 Molecular Memory Tunes Adrenalin to Stress

Library: MED 
Keywords: ADRENALINE EPINEPHRINE ADRENAL GLAND STRESS MEMORY MOLECULAR
CORNELL 
Description: Cornell University neurobiologists, studying the adrenal 
glands of rats, have discovered how
chronic stress cranks up the intensity of thes adrenaline response. The key 
to this so-called molecular
memory resides in a donut-shaped protein on the surface of cells that 
secrete adrenaline, the hormone also
known as epinephrine. 


FOR RELEASE: April 17, 1998 

Contact: Roger Segelken Office: (607) 255-9736 Internet: hrs2@cornell.edu 
Compuserve: Bill Steele,
72650,565 http://www.news.cornell.edu 

ITHACA, N.Y. -- In the rat race of life, a sudden demand from the boss can 
trigger an adrenaline surge
that quickens your pulse, raises blood pressure, kick-starts anxiety and 
prepares you for "fight or flight." 

Now Cornell University neurobiologists, studying the adrenal glands of 
rats, have discovered how chronic
stress cranks up the intensity of this adrenaline response. The key to this 
so-called molecular memory
resides in a donut-shaped protein on the surface of cells that secrete 
adrenaline, the hormone also known
as epinephrine. 

"The hormonal response to stress is different for every individual, and 
seems to be controlled by some
combination of inheritance and lifestyle," explains David P. McCobb, 
co-author along with Jiuyong Xie of
a report in the April 17 issue of the journal Science. "Our study points to 
the effect of lifestyle. Stressful
experience is remembered, and biases us toward responding forcefully to 
subsequent threats," McCobb
says. 

Improved understanding of chemical signaling cascades in the endocrine 
system could lead to better
medical therapies -- perhaps even gene therapy -- for conditions such as 
hypertension and heart attack,
predict McCobb, an assistant professor of neurobiology and behavior, and 
Xie, a postdoctoral researcher
in the McCobb's department. 

"Whether our stress responses are controlled by genes or lifestyle, we'd 
like to have more control,"
McCobb says. "We don't want to secrete more adrenaline than necessary. 
There's a definite adaptive
advantage to being able to back off." 

The Cornell researchers report that adrenal cells dump adrenaline into the 
blood at a rate that is determined
not only by the necessary incoming neural signals from the brain, but also 
by the intrinsic electrical
excitability of the adrenal cells themselves. That excitability is 
determined by the structural detail of the
donut-shaped channel proteins that allow potassium electrical signals to 
cross the cell membrane. And the
structural detail is controlled at the gene level by steroids, according to 
the researchers. 

Forceful heart, lung, metabolic and behavioral reactions help cope with 
acute threats, McCobb says, "but
those reactions are not healthful in the long run. We found that steroid 
stress hormones dictate whether
the potassium channels controlling adrenaline release are constructed with 
or without an optional piece
called STREX, for stress exon. This STREX exon causes the channel to open 
more easily, which favors
rapid, excitable responses and fast secretion of adrenaline." 

To test the theory, the Cornell researchers surgically removed several 
rats' pituitary glands, the source of
ACTH (adrenocorticotropic hormone), a key link in the stress hormone 
cascade. Without pituitary glands,
the percentage of STREX-type channels dropped sharply. This was prevented 
by injecting ACTH
artificially. 

Source: http://www.newswise.com/articles/1998/4/ADRENAL.CNS.html


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Links:
 http://www.stmarys.medford.or.us/curriculum/bio/hbsm/glands/adrenal.htm
 http://www.ncbi.nlm.nih.gov/PubMed/        If you type "adrenaline", you 
get close to 90,000 hits!

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I hope this helps.  If you are looking for something more specific, then
send your question and I will be glad to respond.

Arash E.
Genetics
UBC