title: Optogenetic measurement of presynaptic calcium transients using conditional genetically encoded calcium indicator expression in dopaminergic neurons.
abstract: Calcium triggers dopamine release from presynaptic terminals of midbrain dopaminergic (mDA) neurons in the striatum. However, calcium transients within mDA axons and axon terminals are difficult to study and little is known about how they are regulated. Here we use a newly-developed method to measure presynaptic calcium transients (PreCaTs) in axons and terminals of mDA neurons with a genetically encoded calcium indicator (GECI) GCaMP3 expressed in transgenic mice. Using a photomultiplier tube-based system, we measured electrical stimulation-induced PreCaTs of mDA neurons in dorsolateral striatum slices from these mice. Single-pulse stimulation produced a transient increase in fluorescence that was completely blocked by a combination of N- and P/Q-type calcium channel blockers. DA and cholinergic, but not serotoninergic, signaling pathways modulated the PreCaTs in mDA fibers. These findings reveal heretofore unexplored dynamic modulation of presynaptic calcium in nigrostriatal terminals.
authors.affiliation: Transgenics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Sgobio
authors.affiliation: Laboratory of Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Kupferschmidt
authors.affiliation: Laboratory of Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Guohong
authors.initials: G
authors.lastname: Cui
authors.affiliation: Transgenics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Lixin
authors.initials: L
authors.lastname: Sun
authors.affiliation: Unit on Synapse Development and Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Transgenics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Huaibin
authors.initials: H
authors.lastname: Cai
authors.affiliation: Laboratory of Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: David M
authors.initials: DM
authors.lastname: Lovinger
mesh_terms: D000200:Action Potentials; D000818:Animals; D001369:Axons / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D059290:Dopaminergic Neurons / Q000378:metabolism*; D005453:Fluorescence; D018398:Homeodomain Proteins / Q000378:metabolism; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017072:Neostriatum / Q000378:metabolism; D062308:Optogenetics / Q000379:methods*; D010641:Phenotype; D017729:Presynaptic Terminals / Q000378:metabolism*; D011597:Psychomotor Performance; D011950:Receptors, Cholinergic / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D015398:Signal Transduction; D009435:Synaptic Transmission; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D018398:Homeodomain Proteins; D011950:Receptors, Cholinergic; D014157:Transcription Factors; C433629:homeobox protein PITX3; D012701:Serotonin; D002118:Calcium