Glial cells transform glucose to alanine, which fuels the neurons in the honeybee retina

摘要: The retina of honeybee drone is a nervous tissue with crystal-like structure in which glial cells and photoreceptor neurons constitute two distinct metabolic compartments. phosphorylation glucose its subsequent incorporation into glycogen occur glia, whereas O2 consumption (QO2) occurs the photoreceptors. Experimental evidence showed that glia phosphorylate supply photoreceptors substrates. We aimed to identify these transferred Using ion-exchange reversed-phase HPLC gas chromatography-mass spectrometry, we demonstrated more than 50% 14C(U)-glucose entering transformed alanine by transamination pyruvate glutamate. In absence extracellular glucose, used make alanine; thus, pool size isolated retinas maintained stable or even increased. Our model proposes formation thereby maintaining redox potential this cell contributing NH3 homeostasis. Alanine released space then transported using an Na(+)-dependent transport system. Purified suspensions have similar aminotransferase activity as transform 14C-alanine glutamate, aspartate, CO2. Therefore, transaminated pyruvate, turn enters Krebs cycle. Proline also supplies cycle making glutamate and, turn, intermediate alpha-ketoglutarate. Light stimulation caused 200% increase QO2 decrease proline Also, production 14CO2 from 14C-proline was use amino acids would sustain about half light-induced delta QO2, other being sustained via formation. meets necessary anaplerotic function cycle, but implies high production. results fixes at rate exceeding glutamine This consistent rise upon photostimulation. conclusion, strongly support nutritive for glia.