X-Message-Number: 24328 From: "Basie" <> Subject: Laser microscopy technique settles long debate Date: Sun, 4 Jul 2004 16:41:09 -0400 Laser microscopy technique settles long debate about brain chemistry, could aid studies of Alzheimer's and stroke damage, Cornell biophysicists report EMBARGOED UNTIL THURSDAY, JULY 1, 2004, 2 P.M., EST Contact: Roger Segelken Office: 607-255-9736 E-Mail: Starburst-shaped astrocytes (red cells) and neurons (blue cells) were labeled with specific antibodies in this fixed rat brain section. Because NADH, the coenzyme involved in brain metabolism, fluoresces differently in astrocytes and neurons in living brain tissue, biophysicists at Cornell could determine precisely when astrocytes were providing extra lactate 'fuel' to neurons, confirming the controversial astrocyte-neuron lactate shuttle hypothesis. Copyright Credit: K. Kasischke,P. Fisher/Cornell University Click on the image for a high-resolution version (2.9MB) Proof of activity-dependent metabolism in two kinds of brain cells, neurons undergoing oxidative metabolism show up as green speckles while astrocytes with glycolytic metabolism are red in this multiphoton microscopy scan of living rat brain tissue. Copyright Credit: K. Kasischke/Cornell DRBIO ITHACA, N.Y. -- A laser-based microscopy technique may have settled a long-standing debate among neuroscientists about how brain cells process energy -- while explaining what's really happening in PET (positron emission tomography) imaging and offering a better way to observe the damage that strokes and neurodegenerative diseases, such as Alzheimer's, wreak on brain cells. Multi-photon microscopy scans by Cornell University biophysicists of living brain tissue, as reported in the latest issue of Science (July 2, 2004), reveal exactly how and when neurons (the cells that do the thinking) and astrocytes (the starburst-shaped glial cells that service neurons) interact to burn oxygen and glucose, after astrocytes make lactate from glucose in the bloodstream, to meet the extraordinary energy demands of the brain. Based on imaging of two different energy states of NADH (nicotinamide adenine dinucleotide, a coenzyme involved in brain-cell metabolism), the Cornell biophysicists say they have both confirmed and redefined the controversial "astrocyte-neuron lactate shuttle" hypothesis for brain energy metabolism. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=24328