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