10.1184/R1/6104396.v1 Jason B. Castro Jason B. Castro Nathan Urban Nathan Urban Subthreshold glutamate release from mitral cell dendrites. Carnegie Mellon University 2009 Animals Newborn Bicuculline Biophysics Calcium Dendrites Dose-Response Relationship Drug Drug Interactions Electric Stimulation Excitatory Amino Acid Antagonists GABA Antagonists Glutamic Acid Inhibitory Postsynaptic Potentials Membrane Potentials Methoxyhydroxyphenylglycol Mice Olfactory Bulb Patch-Clamp Techniques Pyridazines Receptors Metabotropic Glutamate Sensory Receptor Cells 2009-05-27 00:00:00 Journal contribution https://kilthub.cmu.edu/articles/journal_contribution/Subthreshold_glutamate_release_from_mitral_cell_dendrites_/6104396 <p>The dendrites of a number of neuron types function as presynaptic structures, releasing transmitter after action potentials and dendritic spikes. In this regard, dendrites can function like axons, producing discrete outputs after suprathreshold electrical events. However, as the major site of synaptic inputs, dendrites experience ongoing subthreshold fluctuations in membrane potential, raising the question of whether these subthreshold changes can cause changes in transmitter release. Here, we show that mitral cells of the accessory olfactory bulb release glutamate from their dendrites in response to both subthreshold and suprathreshold stimuli. Whereas subthreshold output was typically low under control conditions, it could be enhanced several fold by pharmacological or endogenous activation of group I metabotropic glutamate receptors. These results indicate that presynaptic dendrites can support two distinct forms of output, and can dynamically regulate how electrical activity is coupled to transmitter release.</p>