"The brain comprises 2% of the body’s mass, but uses 20% of its resting energy. This massive energy use is vital for neuronal computation : the energy is mainly used on pumping out the ions that enter during synaptic and action potentials. In this lecture I will first review how much energy the brain uses, and how the human body evolved to be able to use so much energy on neuronal information processing. I will then examine what subcellular processes the brain needs ATP for (such as synaptic currents, action potentials, maintaining the resting potential), and thereby demonstrate that energy use severely constrains the “design” of several features of neurons, including the affinity of AMPA receptors and the size of synaptic boutons. After reviewing how brain energy is generated, I will examine how the energy supply is regulated at the vascular level. Although the dogma is that this regulation is carried out by arterioles, I will focus on a recently discovered mechanism by which contractile cells called pericytes may control blood flow by regulating capillary diameter. I will then turn to how the energy supply is controlled at the level of individual neurons, examining how mitochondria are “parked” at active synapses to provide them with ATP. I will compare energy use in the white and grey matter and account for the fact that the white matter uses much less energy. Finally I will describe how energetic failure, in conditions like stroke, spinal cord injury and cerebral palsy, leads to a reversal of glutamate transporters which release glutamate into the extracellular space and thus causes mental and physical impairment by damaging neurons and oligodendrocytes."
Prof David Attwell is a leading neuroscientist and the Jodrell Professor of Physiology at University College London. He uses electrophysiological recording and imaging techniques to study neurotransmitter signalling between nerve and glial cells in the central nervous system.Cliquer ICI pour fermer
Dernière mise à jour : 19/04/2012