Alteration of AMPA Receptor-Mediated Synaptic Transmission by Alexa Fluor 488 and 594 in Cerebellar Stellate Cells.
The fluorescent dyes, Alexa Fluor 488 and 594 are commonly used to visualize dendritic structures and the localization of synapses, both of which are critical for the spatial and temporal integration of synaptic inputs. However, the effect of the dyes on synaptic transmission is not known. Here we investigated whether Alexa Fluor dyes alter the properties of synaptic currents mediated by two subtypes of AMPA receptors (AMPARs) at cerebellar stellate cell synapses. In naive mice, GluA2-lacking AMPAR-mediated synaptic currents displayed an inwardly rectifying current-voltage (I-V) relationship due to blockade by cytoplasmic spermine at depolarized potentials. We found that the inclusion of 100 µm Alexa Fluor dye, but not 10 µm, in the pipette solution led to a gradual increase in the amplitude of EPSCs at +40 mV and a change in the I-V relationship from inwardly rectifying to more linear. In mice exposed to an acute stress, AMPARs switched to GluA2-containing receptors, and 100 µm Alexa Fluor 594 did not alter the I-V relationship of synaptic currents. Therefore, a high concentration of Alexa Fluor dye changed the I-V relationship of EPSCs at GluA2-lacking AMPAR synapses.
Department of Cell Biology and Anatomy, LSU Health Sciences Center New Orleans , New Orleans, Louisiana 70112.
Matthieu
0000-0003-2694-0773
M
Maroteaux
Department of Cell Biology and Anatomy, LSU Health Sciences Center New Orleans , New Orleans, Louisiana 70112.
Siqiong June
SJ
Liu
D000818:Animals; D002491:Central Nervous System Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D002531:Cerebellum / Q000187:drug effects* / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000502:physiology; D004058:Diffusion; D004305:Dose-Response Relationship, Drug; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005456:Fluorescent Dyes / Q000493:pharmacokinetics / Q000494:pharmacology; D005589:Foxes; D006834:Hydrazines / Q000494:pharmacology*; D008297:Male; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009930:Organic Chemicals / Q000493:pharmacokinetics / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D018091:Receptors, AMPA / Q000378:metabolism*; D013096:Spermine / Q000494:pharmacology; D013315:Stress, Psychological / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D046509:Tissue Culture Techniques; D014556:Urine
C417561:Alexa 488 hydrazide; C417664:Alexa594; D002491:Central Nervous System Agents; D005456:Fluorescent Dyes; D006834:Hydrazines; D009930:Organic Chemicals; D018091:Receptors, AMPA; D013096:Spermine
Alexa Fluor 488; Alexa Fluor 594; Ca-permeable AMPA receptors; GluA2-lacking AMPA receptors; cerebellar stellate cells; glutamate; synaptic transmission