Name: an inexpensive, scalable behavioral assay for measuring ethanol sedation sensitivity and rapid tolerance in drosophila
Uploaded: 2015-04-15T14:00:00
Description: Watch this Scientific Journal Video about An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila at JoVE.com

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>

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...

Watch this Scientific Journal Video about An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila at JoVE.com

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 ...

an-inexpensive-scalable-behavioral-assay-for-measuring-ethanol

Research

JoVE Journal

Neuroscience

Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in rodents have shown a direct link between testosterone and aggressive behavior1 and folk wisdom adapts these findings to humans, suggesting that testosterone induces antisocial, egoistic or even aggressive behavior2. However, many researchers doubt a direct testosterone-aggression link in humans, arguing instead that testosterone is primarily involved in status-related behavior3,4. As a high status can also be achieved by aggressive and antisocial means it can be difficult to distinguish between anti-social and status seeking behavior.
We therefore set up an experimental environment, in which status can only be achieved by prosocial means. In a double-blind and placebo-controlled experiment, we administered a single sublingual dose of 0.5 mg of testosterone (with a hydroxypropyl-&beta;-cyclodextrin carrier) to 121 women and investigated their social interaction behavior in an economic bargaining paradigm. Real monetary incentives are at stake in this paradigm; every player A receives a certain amount of money and has to make an offer to another player B on how to share the money. If B accepts, she gets what was offered and player A keeps the rest. If B refuses the offer, nobody gets anything. A status seeking player A is expected to avoid being rejected by behaving in a prosocial way, i.e. by making higher offers.
The results show that if expectations about the hormone are controlled for, testosterone administration leads to a significant increase in fair bargaining offers compared to placebo. The role of expectations is reflected in the fact that subjects who report that they believe to have received testosterone make lower offers than those who say they believe that they were treated with a placebo. These findings suggest that the experimental economics approach is sensitive for detecting neurobiological effects as subtle as those achieved by administration of hormones. Moreover, the findings point towards the importance of both psychosocial as well as neuroendocrine factors in determining the influence of testosterone on human social behavior.

The procedure described in this protocol shows that testosterone administration and folk beliefs about testosterone may be associated with directly opposed social behaviors.

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in ...

A Simple Way to Measure Ethanol Sensitivity in Flies

Low doses of ethanol cause flies to become hyperactive, while high doses are sedating. The sensitivity to ethanol-induced sedation of a given fly strain is correlated with that strain s ethanol preference, and therefore sedation is a highly relevant measure to study the genetics of alcohol responses and drinking. We demonstrate a simple way to expose flies to ethanol and measure its intoxicating effects. The assay we describe can determine acute sensitivity, as well as ethanol tolerance induced by repeat exposure. It does not require a technically involved setup, and can therefore be applied in any laboratory with basic fly culture tools.

A simple assay to measure the sedating effects of ethanol on Drosophila flies, based on the loss of righting reflex, is described.

Low doses of ethanol cause flies to become hyperactive, while high doses are sedating. The sensitivity to ethanol-induced sedation of a given fly strain ...

Microdialysis of Ethanol During Operant Ethanol Self-administration and Ethanol Determination by Gas Chromatography

Operant self-administration methods are commonly used to study the behavioral and pharmacological effects of many drugs of abuse, including ethanol. However, ethanol is typically self-administered orally, rather than intravenously like many other drugs of abuse. The pharmacokinetics of orally administered drugs are more complex than intravenously administered drugs. Because understanding the relationship between the pharmacological and behavioral effects of ethanol requires knowledge of the time course of ethanol reaching the brain during and after drinking, we use in vivo microdialysis and gas chromatography with flame ionization detection to monitor brain dialysate ethanol concentrations over time. 
Combined microdialysis-behavioral experiments involve the use of several techniques. In this article, stereotaxic surgery, behavioral training and microdialysis, which can be adapted to test a multitude of self-administration and neurochemical centered hypotheses, are included only to illustrate how they relate to the subsequent phases of sample collection and dialysate ethanol analysis. Dialysate ethanol concentration analysis via gas chromatography with flame-ionization detection, which is specific to ethanol studies, is described in detail. Data produced by these methods reveal the pattern of ethanol reaching the brain during the self-administration procedure, and when paired with neurochemical analysis of the same dialysate samples, allows conclusions to be made regarding the pharmacological and behavioral effects of ethanol.

A method to determine the time course of ethanol concentration in the brains of rats during operant ethanol self-administration is described. Gas chromatography with flame ionization detection is used to quantify ethanol in the dialysate samples, because it has the sensitivity required for the small volumes that are generated.

Operant self-administration methods are commonly used to study the behavioral and pharmacological effects of many drugs of abuse, including ethanol.  ...

Measuring Changes in Tactile Sensitivity in the Hind Paw of Mice Using an Electronic von Frey Apparatus

Measuring inflammation-induced changes in thresholds of hind paw withdrawal from mechanical pressure is a useful technique to assess changes in pain perception in rodents. Withdrawal thresholds can be measured first at baseline and then following drug, venom, injury, allergen,&#160;or otherwise evoked inflammation by applying an accurate force on very specific areas of the skin. An electronic von Frey apparatus allows precise assessment of mouse hind paw withdrawal thresholds that are not limited by the available filament sizes in contrast to classical von Frey measurements. The ease and rapidity of measurements allow for incorporation of assessment of tactile sensitivity outcomes in diverse models of rapid-onset inflammatory and neuropathic pain as multiple measurements can be taken within a short time period. Experimental measurements for individual rodent subjects can be internally controlled against individual baseline responses and exclusion criteria easily established to standardize baseline responses within and across experimental groups. Thus, measurements using an electronic von Frey apparatus represent a useful modification of the well-established classical von Frey filament-based assays for rodent mechanical allodynia that may also be applied to other nonhuman mammalian models.

Electronic von Frey measurements are an effective and improved alternative to classical von Frey filaments, as they allow rapid and precise measurement of changes in rodent mechanical withdrawal thresholds to continuously applied pressure stimuli before and after an inflammatory event.

Measuring inflammation-induced changes in thresholds of hind paw withdrawal from mechanical pressure is a useful technique to assess changes in pain ...

A Simple and Inexpensive Method for Determining Cold Sensitivity and Adaptation in Mice

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity.
Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 &#176;C to 5 &#176;C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above.
This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

The Cold Plantar Assay (CPA) measures cold responsiveness between 30 &#176;C and 5 &#176;C, and can also measure cold adaptation. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life.  The cold ...

An Assay for Measuring the Effects of Ethanol on the Locomotion Speed of Caenorhabditis elegans

Alcohol use disorders are a significant public health concern, for which there are few effective treatment strategies. One difficulty that has delayed the development of more effective treatments is the relative lack of understanding of the molecular underpinnings of the effects of ethanol on behavior. The nematode, Caenorhabditis elegans (C.&#160;elegans), provides a useful model in which to generate and test hypotheses about the molecular effects of ethanol. Here, we describe an assay that has been developed and used to examine the roles of particular genes and environmental factors in behavioral responses to ethanol, in which locomotion is the behavioral output. Ethanol dose-dependently causes an acute depression of crawling on an agar surface. The effects are dynamic; animals exposed to a high concentration demonstrate an initial strong depression of crawling, referred to here as initial sensitivity, and then partially recover locomotion speed despite the continued presence of the drug. This ethanol-induced behavioral plasticity is referred to here as the development of acute functional tolerance. This assay has been used to demonstrate that these two phenotypes are distinct and genetically separable. The straightforward locomotion assay described here is suitable for examining the effects of both genetic and environmental manipulations on these acute behavioral responses to ethanol in C.&#160;elegans.

An Assay for Measuring the Effects of Ethanol on the Locomotion Speed of Caenorhabditis elegans

C. elegans is a useful model for studying the effects of ethanol on behavior. We present a behavioral assay that quantifies the effects of ethanol on the locomotion speed of crawling worms; both initial sensitivity and the development of acute functional tolerance to ethanol can be measured with this assay.

Alcohol use disorders are a significant public health concern, for which there are few effective treatment strategies. One difficulty that has delayed the ...

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense organs provide an excellent model system for the study of mechanosensation. This protocol describes a simple touch behavior in fruit flies which can be used to identify mutations that interfere with mechanosensation. The tactile stimulation of a macrochaete bristle on the thorax of flies elicits a grooming reflex from either the first or third leg. Mutations that interfere with mechanotransduction (such as NOMPC), or with other aspects of the reflex arc, can inhibit the grooming response. A traditional screen of adult behaviors would have missed mutants that have essential roles during development. Instead, this protocol combines the touch screen with mosaic analysis with a repressible cell marker (MARCM) to allow for only limited regions of homozygous mutant cells to be generated and marked by the expression of green fluorescent protein (GFP). By testing MARCM clones for abnormal behavioral responses, it is possible to screen a collection of lethal p-element mutations to search for new genes involved in mechanosensation that would have been missed by more traditional methods.

A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster

In order to identify novel mutations affecting mechanosensation, we designed an assay that measures the behavioral response to tactile stimulation of fly bristles in mutant clones generated by the MARCM method. The combination of techniques allows for the identification of mechanosensitive mutations that would otherwise be lethal.

Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense ...

Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo

Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method described here enables the investigator to measure long-lasting (from minutes to hours) high-quality intracellular responses from single Drosophila R1-R6 photoreceptors and Large Monopolar Cells (LMCs) to light stimuli. Because the recording system has low noise, it can be used to study variability among individual cells in the fly eye, and how their outputs reflect the physical properties of the visual environment. We outline all key steps in performing this technique. The basic steps in constructing an appropriate electrophysiology set-up for recording, such as design and selection of the experimental equipment are described. We also explain how to prepare for recording by making appropriate (sharp) recording and (blunt) reference electrodes. Details are given on how to fix an intact fly in a bespoke fly-holder, prepare a small window in its eye and insert a recording electrode through this hole with minimal damage. We explain how to localize the center of a cell's receptive field, dark- or light-adapt the studied cell, and to record its voltage responses to dynamic light stimuli. Finally, we describe the criteria for stable normal recordings, show characteristic high-quality voltage responses of individual cells to different light stimuli, and briefly define how to quantify their signaling performance. Many aspects of the method are technically challenging and require practice and patience to master. But once learned and optimized for the investigator's experimental objectives, it grants outstanding in vivo neurophysiological data.

Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo

Sharp microelectrodes enable accurate electrophysiological characterization of photoreceptor and visual interneuron output in living Drosophila. Here we show how to use this method to record high-quality voltage responses of individual cells to controlled light stimulation. This method is ideal for studying neural information processing in insect compound eyes.

Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method ...

Measuring and Altering Mating Drive in Male Drosophila melanogaster

Despite decades of investigation, the neuronal and molecular bases of motivational states remain mysterious. We have recently developed a novel, reductionist, and scalable system for in-depth investigation of motivation using the mating drive of male Drosophila&#160;melanogaster (Drosophila), the methods for which we detail here. The behavioral paradigm centers on the finding that male mating drive decreases alongside fertility over the course of repeated copulations and recovers over ~3 d. In this system, the powerful neurogenetic tools available in the fly converge with the genetic accessibility and putative wiring diagram available for sexual behavior. This convergence allows rapid isolation and interrogation of small neuronal populations with specific motivational functions. Here we detail the design and execution of the satiety assay that is used to measure and alter courtship motivation in the male fly. Using this assay, we also demonstrate that low male mating drive can be overcome by stimulating dopaminergic neurons. The satiety assay is simple, affordable, and robust to influences of genetic background. We expect the satiety assay to generate many new insights into the neurobiology of motivational states.

Measuring and Altering Mating Drive in Male Drosophila melanogaster

This article describes a behavioral assay that uses male mating drive in Drosophila melanogaster to study motivation. Using this method, researchers can utilize advanced fly neurogenetic techniques to uncover the genetic, molecular, and cellular mechanisms that underlie this motivation.

Despite decades of investigation, the neuronal and molecular bases of motivational states remain mysterious. We have recently developed a novel, ...

Novel Assay for Cold Nociception in Drosophila Larvae

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory machinery, such as in patients experiencing peripheral neuropathy or injury-induced sensitization, are not well characterized. The genetically tractable Drosophila model has been used to study the cells and genes required for noxious heat detection, which has yielded multiple conserved genes of interest. Little is known however about the cells and receptors important for noxious cold sensing. Although, Drosophila does not survive prolonged exposure to cold temperatures (&#8804;10 &#186;C), and will avoid cool, preferring warmer temperatures in behavioral preference assays, how they sense and possibly avoid noxious cold stimuli has only recently been investigated.
Here we describe and characterize the first noxious cold (&#8804;10 &#186;C) behavioral assay in Drosophila. Using this tool and assay, we show an investigator how to qualitatively and quantitatively assess cold nociceptive behaviors. This can be done under normal/healthy culture conditions, or presumably in the context of disease, injury or sensitization. Further, this assay can be applied to larvae selected for desired genotypes, which might impact thermosensation, pain, or nociceptive sensitization. Given that pain is a highly conserved process, using this assay to further study&#160;thermal nociception will likely glean important understanding of pain processes in other species, including vertebrates.

Novel Assay for Cold Nociception in Drosophila Larvae

Here we demonstrate a novel assay to study cold nociception in Drosophila larvae. This assay utilizes a custom-built Peltier probe capable of applying a focal noxious cold stimulus and results in quantifiable cold-specific behaviors. This technique will allow further cellular and molecular dissection of cold nociception.

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory ...