X-Message-Number: 18719
Date: Thu, 07 Mar 2002 21:46:44 -0800
From: Kennita Watson <>
Subject: How long ago did they say we couldn't grow new neurons?

I'll call out one significant paragraph before the body of the article:

	Several stimuli increase neurogenesis, including exercise, hippocampal
	dependent learning--"memory formation that involves spatial cues," Dr.
	Duman explained--and estrogen. Additional such factors are expanded
	learning opportunities and increased social interaction. 

Here's the whole thing.  I love the Web!
Kennita
(P.S.:  Another argument for square dancing!  Rah! :-) )

   Antidepressants Enhance Neurogenesis in Adult Rodent Hippocampus

NEW YORK (Reuters Health) Feb 25 - Serotonin and norepinephrine selective
reuptake inhibitors, monoamine oxidase inhibitors, and electroconvulsive
seizures increase neurogenesis in the adult rat hippocampus, according to
findings presented at the 168th annual meeting of the American Academy for
the Advancement of Science. These findings point to mechanisms possibly
involved in successful treatment of mood disorders. 

"The two big effects of stress and glucocorticoid activation in the
mammalian brain are atrophy of dendritic arborization and a decrease in the
formation of new neurons," Dr. Ronald S. Duman, of the Yale University
School of Medicine in New Haven, Connecticut, said in an interview with
Reuters Health. The end result in depressive and posttraumatic stress
disorders is decreased volume of the hippocampus. 

Several stimuli increase neurogenesis, including exercise, hippocampal
dependent learning--"memory formation that involves spatial cues," Dr.
Duman explained--and estrogen. Additional such factors are expanded
learning opportunities and increased social interaction. 

Dr. Fred H. Gage, of the Salk Institute in La Jolla, California, added that
the new neurons exhibit functional integration in the adult hippocampal
circuitry. 

Administration of antidepressants for at least 2 to 4 weeks up-regulates
the cAMP-cAMP response element binding protein (CREB) cascade via
phosphorylation of CREB, as well as the expression of brain derived
neurotrophic factor (BDNF) in the hippocampus, Dr. Duman showed. 

"CREB is the second messenger in brain and other cells that activates the
intracellular signaling cascade that leads to activation of transcription
factors," Dr. Duman said to Reuters Health. This up-regulation appears to
be responsible for the increased hippocampal neurogenesis. 

Furthermore, he added, rodent experiments show that the decrease in
neurogenesis and the behavioral helplessness caused by inescapable
footshock are reversed by administration of fluoxetine. 

"Although the hippocampus does not directly influence mood, connections
with other brain regions such as the amygdala and prefrontal cortex could
result in regulation of emotional states," Dr. Duman said in his
presentation. 

"It appears that there could be remarkable potential for control of neuron
birth and incorporation in the normal, diseased, and injured adult brain,
if cellular and molecular controls over these events can be harnessed and
manipulated," Dr. Gage concluded. 

   Reuters Health Information 2002.   2002 Reuters Ltd
-- 
May you live long and prosper,
Kennita
--
Kennita Watson          | Emancipate yourselves from mental slavery;
     |   None but ourselves can free our minds.
http://www.kennita.com  |           -- Bob Marley, "Redemption Song"

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=18719