High osmolarity and L-DOPA augment release via the fusion pore in PC12 cells.
We have amperometrically measured dopamine release from rat pheochromocytoma cells (PC12 cells) in high osmolarity conditions with and without L-3,4-dihydroxyphenylalanine (L-DOPA) treatment. We observe an increase in the number of release events displaying a prespike feature or "foot" when the cells are stimulated in high osmolarity saline. We also see an increase in foot area and duration when cells are stimulated in high osmolarity saline, or high osmolarity saline subsequent to incubation with the dopamine precursor L-DOPA in isotonic saline, which serves to increase the vesicle size. The data suggest that membrane biophysics are an important component in defining the rate, duration and amount of neurotransmitter release via the fusion pore.
Sombers
Leslie A
LA
Department of Chemistry, The Pennsylvania State University, 102 Chemistry Building, University Park, PA 16802, USA.
Wittenberg
Nathan J
NJ
Maxson
Marc M
MM
Adams
Kelly L
KL
Ewing
Andrew G
AG
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D021961:Cell Membrane Structures / Q000187:drug effects* / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005089:Exocytosis / Q000187:drug effects; D007980:Levodopa / Q000494:pharmacology*; D008954:Models, Biological; D009994:Osmolar Concentration; D016716:PC12 Cells; D016062:Porosity / Q000187:drug effects; D051381:Rats
D007980:Levodopa; D004298:Dopamine