Norepinephrine stimulates glycogenolysis in astrocytes to fuel neurons with lactate
Fig 2
Noradrenergic modulation in glia.
A) Schematic compartmental diagram of the NGV model with noradrenergic locus coeruleus (LC) inputs, astrocyte, extracellular and neuronal compartments. The vasculature blood flow has been clamped for these simulations for simplicity. B) Distance of NE release site from astrocyte was simulated as differences in rise time constant (four NE waveforms with τrise = 1, 10, 100 and 1000 sec). C) Corresponding NE receptor (β2R) activation levels show maximum receptor activation to each NE waveform. Inset: time domain zoom. Astrocytic β2R receptor activation is largely invariant except within initial 50 ms from neurotransmitter release when source of NE release is varied over 4 orders of magnitude. D) Dose-response relationship for NE and β2R activation (Kd = 300 nM). E) cAMP production levels in response to 1 second pulses of NE and τrise = 10 (representing a constant, relatively close proximity of the LC input, see S1 Text) at 4 different adenylate cyclase amplification factors selected in order to empirically produce a wide dynamic range of cAMP. Inset: time domain zoom. NE duration indicated by gray shaded areas.