The biphasic NAD(P)H fluorescence response of astrocytes to dopamine reflects the metabolic actions of oxidative phosphorylation and glycolysis.
The NAD(+)/NADH redox pair constitutes an important metabolic node connecting catabolic pathways to energy production. We took advantage of the fluorescence of NADH to monitor changes in NADH levels by 2-photon laser scanning microscopy in cultured cortical astrocytes and acutely isolated brain slices in response to dopamine (DA), a major neurotransmitter involved in modulation of attention, motivation, and learning. DA induced a dose-dependent biphasic response of the NAD(P)H fluorescence signal, consisting of an initial decrease followed by a subsequent increase. This response was mediated by D1-receptors, protein kinase A, and 5'-AMP-activated protein kinase signaling. While the initial decrease could be inhibited by blocking mitochondrial respiratory chain, the increase was inhibited by blocking glycolysis. Finally, activation of DA receptors on astrocytes in acutely isolated mouse cortical brain slices also induced an increase in the NAD(P)H fluorescence signal. We conclude that DA activates two opposing components of astrocytic metabolism with different kinetics. This response of the astroglial metabolism might contribute to fine-tuned participation of astrocytes to neuronal activity and functional states of the brain.
Requardt
Robert P
RP
Carl-Ludwig-Institute for Physiology and Interdisciplinary Centre for Clinical Research (IZKF), University of Leipzig, Leipzig, Germany.
Wilhelm
Franziska
F
Rillich
Jan
J
Winkler
Ulrike
U
Hirrlinger
Johannes
J
D000818:Animals; D001253:Astrocytes / Q000187:drug effects*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D005576:Colforsin / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism / Q000494:pharmacology*; D015259:Dopamine Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005453:Fluorescence; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal / Q000379:methods; D009243:NAD / Q000378:metabolism*; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
D015259:Dopamine Agents; D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; C485184:enhanced green fluorescent protein; D009243:NAD; D049452:Green Fluorescent Proteins; D005576:Colforsin; D019344:Lactic Acid; D005947:Glucose; D004298:Dopamine