These studies were supported by grants from the National Institutes of Health, National Institute for Alcoholism and Alcohol Abuse to M.G. (P20AA017828, R01AA020634, P50 AA022537). The authors thank Jill Bettinger for helpful discussions and Jacqueline DeLoyht for technical assistance.

1. Day Before Assay
<ol>
	<li>Collect flies into fresh food vials in groups of 11 (single sex) under brief (1-5 min) CO2.</li>
	<li>Allow flies to recover O/N in food vials in an environmentally controlled space (typically 25 &#176;C, 60% relative humidity, 12 hr light/dark cycle).</li>
	<li>Prepare ethanol solution(s) by diluting pure (100%) ethanol in purified (&#8805;18 M&#937;) water to final concentration(s) appropriate for the planned experiment. Allow solution(s) to return to RT O/N. 
	Note: Dilu...

<ol>
	<li>Rehm, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+burden+of+disease+and+injury+and+economic+cost+attributable+to+alcohol+use+and+alcohol-use+disorders.">Global burden of disease and injury and economic cost attributable to alcohol use and alcohol-use disorders.</a> Lancet. 373, 2223-2233 (2009).</li><li>Prescott, C. A., Kendler, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+and+environmental+contributions+to+alcohol+abuse+and+dependence+in+a+population-based+sample+of+male+twins.">Genetic and environmental contributions to alcohol abuse and dependence in a population-based sample of male twins.</a> The American journal of psychiatry. 156, 34-40 (1999).</li><li>Devineni, A. V., Heberlein, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+evolution+of+Drosophila+melanogaster+as+a+model+for+alcohol+research.">The evolution of Drosophila melanogaster as a model for alcohol research.</a> Annual review of neuroscience. 36, 121-138 (2013).</li><li>Scholz, H., Mustard, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invertebrate+Models+of+Alcoholism.">Invertebrate Models of Alcoholism.</a> Current topics in behavioral neurosciences. 13, 433-457 (2011).</li><li>Rodan, A. R., Rothenfluh, A., Reilly, M. T., Lovinger, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Functional Plasticity and Genetic Variation: Insights into the Neurobiology of Alcoholism. 91, (2010).</li><li>Schumann, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+association+and+genetic+functional+studies+identify+autism+susceptibility+candidate+2+gene+(AUTS2)+in+the+regulation+of+alcohol+consumption.">Genome-wide association and genetic functional studies identify autism susceptibility candidate 2 gene (AUTS2) in the regulation of alcohol consumption.</a> Proceedings of the National Academy of Sciences of the United States of America. 108, 7119-7124 (2011).</li><li>Corl, A. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Happyhour,+a+Ste20+family+kinase,+implicates+EGFR+signaling+in+ethanol-induced+behaviors.">Happyhour, a Ste20 family kinase, implicates EGFR signaling in ethanol-induced behaviors.</a> Cell. 137, 949-960 (2009).</li><li>Moore, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol+intoxication+in+Drosophila:+Genetic+and+pharmacological+evidence+for+regulation+by+the+cAMP+signaling+pathway.">Ethanol intoxication in Drosophila: Genetic and pharmacological evidence for regulation by the cAMP signaling pathway.</a> Cell. 93, 997-1007 (1998).</li><li>Scholz, H., Franz, M., Heberlein, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+hangover+gene+defines+a+stress+pathway+required+for+ethanol+tolerance+development.">The hangover gene defines a stress pathway required for ethanol tolerance development.</a> Nature. 436, 845-847 (2005).</li><li>Riley, B. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alcohol+dependence+is+associated+with+the+ZNF699+gene,+a+human+locus+related+to+Drosophila+hangover,+in+the+Irish+affected+sib+pair+study+of+alcohol+dependence+(IASPSAD)+sample.">Alcohol dependence is associated with the ZNF699 gene, a human locus related to Drosophila hangover, in the Irish affected sib pair study of alcohol dependence (IASPSAD) sample.</a> Molecular psychiatry. 11, 1025-1031 (2006).</li><li>Morozova, T. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alcohol+sensitivity+in+Drosophila:+translational+potential+of+systems+genetics.">Alcohol sensitivity in Drosophila: translational potential of systems genetics.</a> Genetics. 183, 733-745 (2009).</li><li>Ogueta, M., Cibik, O., Eltrop, R., Schneider, A., Scholz, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+Adh+function+on+ethanol+preference+and+tolerance+in+adult+Drosophila+melanogaster.">The influence of Adh function on ethanol preference and tolerance in adult Drosophila melanogaster.</a> Chemical senses. 35, 813-822 (2010).</li><li>Han, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrating+GWASs+and+human+protein+interaction+networks+identifies+a+gene+subnetwork+underlying+alcohol+dependence.">Integrating GWASs and human protein interaction networks identifies a gene subnetwork underlying alcohol dependence.</a> American journal of human genetics. 93, 1027-1034 (2013).</li><li>Lind, P. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+genomewide+association+study+of+nicotine+and+alcohol+dependence+in+Australian+and+Dutch+populations.">A genomewide association study of nicotine and alcohol dependence in Australian and Dutch populations.</a> Twin Res Hum Genet. 13, 10-29 (2010).</li><li>Schuckit, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+level+of+response+to+alcohol+as+a+predictor+of+future+alcoholism.">Low level of response to alcohol as a predictor of future alcoholism.</a> The American journal of psychiatry. 151, 184-189 (1994).</li><li>Schuckit, M. A., Smith, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+8-year+follow-up+of+450+sons+of+alcoholic+and+control+subjects.">An 8-year follow-up of 450 sons of alcoholic and control subjects.</a> Archives of general psychiatry. 53, 202-210 (1996).</li><li>Tabakoff, B., Cornell, N., Hoffman, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alcohol+tolerance.">Alcohol tolerance.</a> Ann Emerg Med. 15, 1005-1012 (1986).</li><li>Chan, R. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contrasting+Influences+of+Drosophila+white/mini-white+on+Ethanol+Sensitivity+in+Two+Different+Behavioral+Assays.">Contrasting Influences of Drosophila white/mini-white on Ethanol Sensitivity in Two Different Behavioral Assays.</a> Alcohol Clin Exp Res. 38, 1582-1593 (2014).</li><li>Eddison, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=arouser+reveals+a+role+for+synapse+number+in+the+regulation+of+ethanol+sensitivity.">arouser reveals a role for synapse number in the regulation of ethanol sensitivity.</a> Neuron. 70, 979-990 (2011).</li><li>Wen, T., Parrish, C. A., Xu, D., Wu, Q., Shen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+neuropeptide+F+and+its+receptor,+NPFR1,+define+a+signaling+pathway+that+acutely+modulates+alcohol+sensitivity.">Drosophila neuropeptide F and its receptor, NPFR1, define a signaling pathway that acutely modulates alcohol sensitivity.</a> Proceedings of the National Academy of Sciences of the United States of America. 102, 2141-2146 (2005).</li><li>Bhandari, P., Kendler, K. S., Bettinger, J. C., Davies, A. G., Grotewiel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+assay+for+evoked+locomotor+behavior+in+Drosophila+reveals+a+role+for+integrins+in+ethanol+sensitivity+and+rapid+ethanol+tolerance.">An assay for evoked locomotor behavior in Drosophila reveals a role for integrins in ethanol sensitivity and rapid ethanol tolerance.</a> Alcohol Clin Exp Res. 33, 1794-1805 (2009).</li><li>Bhandari, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloride+intracellular+channels+modulate+acute+ethanol+behaviors+in+Drosophila,+Caenorhabditis+elegans+and+mice.">Chloride intracellular channels modulate acute ethanol behaviors in Drosophila, Caenorhabditis elegans and mice.</a> Genes, brain, and behavior. 11, 387-397 (2012).</li><li>Gargano, J. W., Martin, I., Bhandari, P., Grotewiel, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+iterative+negative+geotaxis+(RING):+a+new+method+for+assessing+age-related+locomotor+decline+in+Drosophila.">Rapid iterative negative geotaxis (RING): a new method for assessing age-related locomotor decline in Drosophila.</a> Experimental gerontology. 40, 386-395 (2005).</li><li>Chen, J., Wang, Y., Zhang, Y., Shen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+in+Bacchus+reveal+a+tyramine-dependent+nuclear+regulator+for+acute+ethanol+sensitivity+in+Drosophila.">Mutations in Bacchus reveal a tyramine-dependent nuclear regulator for acute ethanol sensitivity in Drosophila.</a> Neuropharmacology. 67, 25-31 (2013).</li><li>Lasek, A. W., Giorgetti, F., Berger, K. H., Tayor, S., Heberlein, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lmo+genes+regulate+behavioral+responses+to+ethanol+in+Drosophila+melanogaster+and+the+mouse.">Lmo genes regulate behavioral responses to ethanol in Drosophila melanogaster and the mouse.</a> Alcohol Clin Exp Res. 35, 1600-1606 (2011).</li><li>Maples, T., Rothenfluh, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+way+to+measure+ethanol+sensitivity+in+flies.">A simple way to measure ethanol sensitivity in flies.</a> J Vis Exp. , e2541 (2011).</li><li>Rothenfluh, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+behavioral+responses+to+ethanol+are+regulated+by+alternate+RhoGAP18B+isoforms.">Distinct behavioral responses to ethanol are regulated by alternate RhoGAP18B isoforms.</a> Cell. 127, 199-211 (2006).</li><li>Rothenfluh, A., Troutwine, B. R., Ghezzi, A., Atkinson, N. S., Nohronha, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ch.+23.">Ch. 23.</a> Neurobiology of Alcohol Dependence. 23, 467-495 (2014).</li><li>Jones, M. A., Grotewiel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+as+a+model+for+age-related+impairment+in+locomotor+and+other+behaviors.">Drosophila as a model for age-related impairment in locomotor and other behaviors.</a> Experimental gerontology. 46, 320-325 (2010).</li><li>Martin, I., Grotewiel, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidative+damage+and+age-related+functional+declines.">Oxidative damage and age-related functional declines.</a> Mechanisms of ageing and development. 127, 411-413 (2006).</li><li>Devineni, A. V., Heberlein, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+ethanol+responses+in+Drosophila+are+sexually+dimorphic.">Acute ethanol responses in Drosophila are sexually dimorphic.</a> Proceedings of the National Academy of Sciences of the United States of America. 109, 21087-21092 (2012).</li></ol>

The authors have nothing to disclose.

Straightforward assays that reproducibly quantitate meaningful phenotypes are of great value for the analysis of behavior. The work described here addresses several practical aspects of an assay for measuring ethanol sedation sensitivity and rapid tolerance in Drosophila. Although not a focus of this work, behavioral analyses are facilitated by maintaining the environment and genetic background constant for test subjects within a study. Furthermore, comparisons should typically be made between groups of flies re...

Alcohol use disorder (AUD) is an enormous health problem worldwide (reviewed in 1). Although the mechanisms driving the development of AUD are complex, these disorders have a major genetic component (e.g., 2). The large heritability of AUD&#160;and the conserved behavioral responses to ethanol across many species (reviewed in 3,4) have generated strong interest in using genetic model organisms to investigate the involvement of specific genes in ethanol-related behaviors toward better understanding the molecular basis of AUD. The fruit fly, Drosophila melanogaster, has emerged as a leading model organism for exploring molecular-genetic mechanisms of ethanol-related behaviors (reviewed in 3,4). Studies in flies have highlighted roles for several signaling pathways in behavioral responses to ethanol (reviewed in 5). Intriguingly, some of the genes and pathways that influence behavioral responses to ethanol in flies have also been implicated in rodent ethanol-related behaviors and/or human AUD&#160;(e.g.,&#160;6-14). The conservation of mechanisms driving ethanol-related behaviors across species, coupled with the suite of genetic tools available in the Drosophila model system, underscore the utility of the fruit fly model for investigating the genetics of behavioral responses to ethanol.
Sensitivity 15,16 and tolerance (reviewed in 17) to ethanol in humans is linked to the development of AUD. Both of these behavioral responses to ethanol can be modeled in flies via a variety of laboratory assays (reviewed in 3,4). All of the fly assays known to the authors are based on either time-dependent ethanol-induced sedation/incoordination or time-dependent recovery from ethanol sedation.
In a previous article from our group on the genetics of ethanol sensitivity and rapid tolerance in Drosophila, a behavioral assay based on ethanol vapor-induced sedation of flies was used 18. Testing in this assay was initiated by transferring live adult flies without anesthesia to empty food vials, trapping the flies in the vials with a cellulose acetate plug, adding ethanol to the top (i.e.,&#160;non-fly side) of the cellulose acetate plug, and sealing the vial containing flies, cellulose acetate plug and ethanol with a silicone stopper (see schematic in Figure S3, reference 18). Multiple vials representing different groups of flies were assessed in parallel, increasing throughput of this assay. Vials were given an anonymous code and experimenters were blinded to treatment group to prevent unintended bias in the assessment of sedation. In a standard experiment, flies in vials were tapped gently at 6 min intervals and, after a 30 sec recovery, the number of sedated flies in each vial was counted and converted to percent active flies. Flies absorbed ethanol vapor from the cellulose acetate plug in a time-dependent fashion, causing progressive increases in internal ethanol18 and sedation (c.f. reference 18 and Figure 1A and 1B in this report). Sedation in this assay was operationally defined as flies (i) standing in the absence of walking or (ii) lying on their backs with or without flapping their wings. Here, this ethanol sedation assay is described in detail, further operational optimization relevant to using it is provided, and the assay is used to address the contribution of food supplementation options on fly sedation sensitivity.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>food vials</td>
			<td>VWR</td>
			<td>89092-772</td>
			<td>narrow</td>
		</tr>
		<tr>
			<td>Flugs</td>
			<td>Genesee/flystuff.com</td>
			<td>49-102</td>
			<td>narrow</td>
		</tr>
		<tr>
			<td>silicone stopper</td>
			<td>Fisher Scientific</td>
			<td>09-704-1l</td>
			<td>#4</td>
		</tr>
		<tr>
			<td>ethanol</td>
			<td>Pharmaco-Aaper</td>
			<td>111000200</td>
			<td>200 proof</td>
		</tr>
	</tbody>
</table>

an inexpensive, scalable behavioral assay for measuring ethanol sedation sensitivity and rapid tolerance in drosophila

Alcohol use disorder (AUD) is a serious health challenge. Despite a large hereditary component to AUD, few genes have been unambiguously implicated in their etiology. The fruit fly, Drosophila melanogaster, is a powerful model for exploring molecular-genetic mechanisms underlying alcohol-related behaviors and therefore holds great promise for identifying and understanding the function of genes that influence AUD. The use of the Drosophila model for these types of studies depends on the availability of assays that reliably measure behavioral responses to ethanol. This report describes an assay suitable for assessing ethanol sensitivity and rapid tolerance in flies. Ethanol sensitivity measured in this assay is influenced by the volume and concentration of ethanol used, a variety of previously reported genetic manipulations, and also the length of time the flies are housed without food immediately prior to testing. In contrast, ethanol sensitivity measured in this assay is not affected by the vigor of fly handling, sex of the flies, and supplementation of growth medium with antibiotics or live yeast. Three different methods for quantitating ethanol sensitivity are described, all leading to essentially indistinguishable ethanol sensitivity results. The scalable nature of this assay, combined with its overall simplicity to set-up and relatively low expense, make it suitable for small and large scale genetic analysis of ethanol sensitivity and rapid tolerance in Drosophila.

The raw data from this ethanol sedation assay are the numbers of flies that are sedated as a function of ethanol vapor exposure time. Raw data are converted to the percent active flies as a function of time (primary data, Figures 1A, B, D-F). Sensitivity to ethanol sedation from the primary data can be quantitated as Sedation Time 50 (ST50), the time required for 50% of flies to become sedated or aea under the curve (AUC), via interpolation from curve fi...

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An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila

Straightforward assays for measuring ethanol sensitivity and rapid tolerance in Drosophila facilitate the use of this model organism for investigating these important ethanol-related behaviors. Here, a relatively simple, scalable assay for measuring ethanol sensitivity and rapid tolerance in flies is described.

An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila

Alcohol use disorder (AUD) is a serious health challenge. Despite a large hereditary component to AUD, few genes have been unambiguously implicated in ...

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10.2K Görüntüleme.  Virginia Commonwealth University. Straightforward assays for measuring ethanol sensitivity and rapid tolerance in Drosophila facilitate the use of this model organism for investigating these important ethanol-related behaviors. Here, a relatively simple, scalable assay for measuring ethanol sensitivity and rapid tolerance in flies is described.