Development of fluorescence imaging probes for nicotinic acetylcholine ?4?2? receptors. Academic Article uri icon

abstract

  • Nicotinic acetylcholine ?4?2? receptors (nAChRs) are implicated in various neurodegenerative diseases and smoking addiction. Imaging of brain high-affinity ?4?2? nAChRs at the cellular and subcellular levels would greatly enhance our understanding of their functional role. Since better resolution could be achieved with fluorescent probes, using our previously developed positron emission tomography (PET) imaging agent [18F]nifrolidine, we report here design, synthesis and evaluation of two fluorescent probes, nifrodansyl and nifrofam for imaging ?4?2? nAChRs. The nifrodansyl and nifrofam exhibited nanomolar affinities for the ?4?2? nAChRs in [3H]cytisine-radiolabeled rat brain slices. Nifrofam labeling was observed in ?4?2? nAChR-expressing HEK cells and was upregulated by nicotine exposure. Nifrofam co-labeled cell-surface ?4?2? nAChRs, labeled with antibodies specific for a ?2 subunit extracellular epitope indicating that nifrofam labels ?4?2? nAChR high-affinity binding sites. Mouse brain slices exhibited discrete binding of nifrofam in the auditory cortex showing promise for examining cellular distribution of ?4?2? nAChRs in brain regions.

publication date

  • February 1, 2018