Identification of a fluorescent general anesthetic, 1-aminoanthracene.
We identified a fluorophore, 1-aminoanthracene (1-AMA), that is anesthetic, potentiates GABAergic transmission, and gives an appropriate dissociation constant, K(d) approximately 0.1 mM, for binding to the general anesthetic site in horse spleen apoferritin (HSAF). 1-AMA fluorescence is enhanced when bound to HSAF. Thus, displacement of 1-AMA from HSAF by other anesthetics attenuates the fluorescence signal and allows determination of K(d), as validated by isothermal titration calorimetry. This provides a unique fluorescence assay for compound screening and anesthetic discovery. Additional electrophysiology experiments in isolated cells indicate that 1-AMA potentiates chloride currents elicited by GABA, similar to many general anesthetics. Furthermore, 1-AMA reversibly immobilizes stage 45-50 Xenopus laevis tadpoles (EC(50) = 16 microM) and fluorescence micrographs show 1-AMA localized to brain and olfactory regions. Thus, 1-AMA provides an unprecedented opportunity for studying general anesthetic distribution in vivo at the cellular and subcellular levels.
Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
Christopher A
CA
Butts
Jin
J
Xi
Grace
G
Brannigan
Abdalla A
AA
Saad
Srinivasan P
SP
Venkatachalan
Robert A
RA
Pearce
Michael L
ML
Klein
Roderic G
RG
Eckenhoff
Ivan J
IJ
Dmochowski
D018681:Anesthetics, General / Q000378:metabolism*; D000818:Animals; D000873:Anthracenes / Q000378:metabolism* / Q000494:pharmacology; D001052:Apoferritins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D018118:Chloride Channels / Q000378:metabolism; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism*; D006736:Horses; D015640:Ion Channel Gating / Q000187:drug effects; D007530:Isoflurane / Q000378:metabolism; D007814:Larva / Q000166:cytology / Q000187:drug effects; D018613:Microscopy, Confocal; D009474:Neurons / Q000166:cytology / Q000187:drug effects; D015742:Propofol / Q000378:metabolism; D017433:Protein Structure, Secondary; D013216:Reflex, Startle / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014982:Xenopus laevis / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018681:Anesthetics, General; D000873:Anthracenes; D018118:Chloride Channels; D005456:Fluorescent Dyes; D005680:gamma-Aminobutyric Acid; C049062:1-aminoanthracene; D001052:Apoferritins; D007530:Isoflurane; D015742:Propofol