Assay for General Anesthetic Phenotype in Xenopus Tadpoles
Anesthetic development has remained a largely empirical process. There are growing concerns about the cognitive effects of known general anesthetics  and acceleration of the onset of neurodegenerative disease . The compounds' toxicity  and multiple specific binding targets in the mammalian brain  has made them less attractive as drug leads. This assay was designed for the in vivo follow-up testing of compounds in tadpoles. ..more
BioActive Compounds: 6
Anesthetic development has remained a largely empirical process. There are growing concerns about the cognitive effects of known general anesthetics  and acceleration of the onset of neurodegenerative disease . The compounds' toxicity  and multiple specific binding targets in the mammalian brain  has made them less attractive as drug leads. This assay was designed for the in vivo follow-up testing of compounds in tadpoles.
 S.L. Bianchi, T. Tran, C. Liu, S. Lin, Y. Li, J.M. Keller, R.G. Eckenhoff, and M.F. Eckenhoff, Brain and behavior changes in 12-month-old Tg2576 and nontransgenic mice exposed to anesthetics. Neurobiol Aging 29 (2008) 1002-10.
 Z. Xie, Y. Dong, U. Maeda, R.D. Moir, W. Xia, D.J. Culley, G. Crosby, and R.E. Tanzi, The inhalation anesthetic isoflurane induces a vicious cycle of apoptosis and amyloid beta-protein accumulation. J Neurosci 27 (2007) 1247-54.
 P. Honegger, and J.M. Matthieu, Selective toxicity of the general anesthetic propofol for GABAergic neurons in rat brain cell cultures. J Neurosci Res 45 (1996) 631-6.
 M.F. Eckenhoff, K. Chan, and R.G. Eckenhoff, Multiple specific binding targets for inhaled anesthetics in the mammalian brain. J Pharmacol Exp Ther 300 (2002) 172-9.
 C.A. Butts, J. Xi, G. Brannigan, A.A. Saad, S.P. Venkatachalan, R.A. Pearce, M.L. Klein, R.G. Eckenhoff, and I.J. Dmochowski, Identification of a fluorescent general anesthetic, 1-aminoanthracene. Proc Natl Acad Sci U S A 106 (2009) 6501-6.
 W.A. Lea, J. Xi, A. Jadhav, L. Lu, C.P. Austin, A. Simeonov, and R.G. Eckenhoff, A high-throughput approach for identification of novel general anesthetics. PLoS One 4 (2009) e7150.
Pre-limb bud Xenopus tadpoles were obtained in large batches from Nasco, Inc. Batches of 10 tadpoles were placed in 20 mm Petri dishes with approximately 20 ml of pond water ("pond water" is approximately a 20-fold dilution of Ringers saline solution). Compounds were added to the pond water from DMSO stock to obtain 100, 10 and 1 microM concentrations. Tadpoles were then incubated with these solutions for 1 hour, and then scored for "anesthesia". Anesthesia in this case is lack of movement in response to a sharp tap on the Petri dish lid, i.e., a lack of startle response. This correlates well to the loss of righting reflex in rodents and the loss of consciousness in humans. The pond water is then changed, and the return of a startle response is monitored for 24 hours. Immobility at 24 hours is considered death.
Compounds were considered active if "Percent Immobility at 10uM after 1hr" was greater than 50, inclusive if between 15 and 50, and inactive if less than 15.
PUBCHEM_ACTIVITY_SCORE for actives or inconclusives were set to same as the "Percent Immobility at 10uM at 1hr" and was set to 0 if compound was categorized as inactive.
"Percent Immobility at 10uM at 24hr" represents toxicity. Higher percent immobility implies toxicity.
Data Table (Concise)