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.
Butts
Christopher A
CA
Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
Xi
Jin
J
Brannigan
Grace
G
Saad
Abdalla A
AA
Venkatachalan
Srinivasan P
SP
Pearce
Robert A
RA
Klein
Michael L
ML
Eckenhoff
Roderic G
RG
Dmochowski
Ivan J
IJ
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