Name: self-administration of drugs in mouse models of feeding and obesity
Uploaded: 2021-06-08T15:00:00
Description: Watch this Scientific Journal Video about Self-Administration of Drugs in Mouse Models of Feeding and Obesity at JoVE.com

This work was supported by the National Institutes of Health grant R01DK117872 awarded to OO and the Larry L Hillblom Foundation Fellowship awarded to RCZ.

All procedures involving animal subjects have been approved by the Institutional Animal Care and Use Committee (IACUC) at the University of California, San Diego.
1. Making the drug-peanut butter pellet
<ol>
	<li>Calculate the amount of drug needed to make the desired dose of drug in a pellet of peanut butter and scale to the size of the batch required for an experiment. Importantly, pellets can be kept at -80 &#176;C, depending on drug stability.</li>
	<li>Pulverize the drug tablets using a...

<ol>
	<li>de Meijer, V. E., Le, H. D., Meisel, J. A., Puder, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repetitive+orogastric+gavage+affects+the+phenotype+of+diet-induced+obese+mice.">Repetitive orogastric gavage affects the phenotype of diet-induced obese mice.</a> Physiology and Behavior. 100 (4), 387-393 (2010).</li><li>Perez-Gomez, 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+phenotypic+Caenorhabditis+elegans+screen+identifies+a+selective+suppressor+of+antipsychotic-induced+hyperphagia.">A phenotypic Caenorhabditis elegans screen identifies a selective suppressor of antipsychotic-induced hyperphagia.</a> Nature Communications. 9 (1), 5272 (2018).</li><li>Corbett, A., McGowin, A., Sieber, S., Flannery, T., Sibbitt, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+reliable+voluntary+oral+administration+of+a+fixed+dosage+(mg/kg)+of+chronic+daily+medication+to+rats.">A method for reliable voluntary oral administration of a fixed dosage (mg/kg) of chronic daily medication to rats.</a> Laboratory Animal. 46 (4), 318-324 (2012).</li><li>Teixeira-Santos, L., Albino-Teixeira, A., Pinho, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+alternative+method+for+oral+drug+administration+by+voluntary+intake+in+male+and+female+mice.">An alternative method for oral drug administration by voluntary intake in male and female mice.</a> Laboratory Animal. 55 (1), 76-80 (2021).</li><li>Zhang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+voluntary+oral+administration+of+drugs+in+mice.">Method for voluntary oral administration of drugs in mice.</a> STAR Protocols. 2 (1), 100330 (2021).</li><li>Cope, M. 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=Risperidone+alters+food+intake,+core+body+temperature,+and+locomotor+activity+in+mice.">Risperidone alters food intake, core body temperature, and locomotor activity in mice.</a> Physiology and Behaviour. 96 (3), 457-463 (2009).</li><li>Barton, B. B., Segger, F., Fischer, K., Obermeier, M., Musil, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Update+on+weight-gain+caused+by+antipsychotics:+a+systematic+review+and+meta-analysis.">Update on weight-gain caused by antipsychotics: a systematic review and meta-analysis.</a> Expert Opinion in Drug Safety. 19 (3), 295-314 (2020).</li><li>Cope, M. 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=Antipsychotic+drug-induced+weight+gain:+development+of+an+animal+model.">Antipsychotic drug-induced weight gain: development of an animal model.</a> International Journal of Obesity. 29 (6), 607-614 (2005).</li><li>Domecq, J. 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=Clinical+review:+Drugs+commonly+associated+with+weight+change:+a+systematic+review+and+meta-analysis.">Clinical review: Drugs commonly associated with weight change: a systematic review and meta-analysis.</a> Journal of Clinical Endocrinology and Metabolism. 100 (2), 363-370 (2015).</li><li>Wei, H., 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=Dopamine+D2+receptor+signaling+modulates+pancreatic+beta+cell+circadian+rhythms.">Dopamine D2 receptor signaling modulates pancreatic beta cell circadian rhythms.</a> Psychoneuroendocrinology. 113, 104551 (2020).</li></ol>

When conducting this protocol, it is important to be consistent with the accuracy of the measurements of food intake and body weight and the timing of drug administration throughout the study. While this self-administration method requires a significant training phase, this is particularly important to acclimate the mice to the novelty of the peanut butter and ensure mice consume the drug at the time given. Once established, it also offers great experimental flexibility and can be modified and adapted to deliver drugs at...

The goal of this method is to deliver drugs in mice via a non-invasive, minimally stressful procedure. Preclinical studies in mice often rely on stressful, invasive routes of drug administration that can have significant impacts on metabolic parameters. For example, repetitive daily oral gavage can significantly decrease caloric intake and weight gain in mice1. In addition, oral gavage can be technically challenging and has the potential to cause injuries. As an alternative, mice can self-administer compounds that are mixed in their food or dissolved in their drinking water 2. However, this approach has a major limitation, which is, it relies on the natural circadian timing of food or water intake. Furthermore, drug stability or solubility in water can be major issues when chronically delivered in this way. To overcome these limitations, drugs can be mixed with highly palatable foods, such as cookie dough 3, jelly 4,5 or peanut butter 6 to encourage self-administration in mice at a specified time. This approach has the advantage of facilitating drug delivery with minimal stress compared with an injection or daily gavage1. This procedure can be adapted to deliver a wide variety of drugs to mice. This protocol demonstrates the process of drug preparation, training, followed by drug delivery in highly palatable food. As an example, this method is used to administer the antipsychotic drug risperidone to C57BL/6J female mice. Risperidone is well known to have potent hyperphagic and weight gain effects in patients 7 that is well modelled in rodents 6,8. This system of administration facilitates a highly translational model that could be used to study a wide variety of drugs and their effects on pathways regulating food intake and body weight 9.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>C57B6/J mice</td>
			<td>Jackson Labs, Sacramento, CA, USA</td>
			<td>664</td>
			<td></td>
		</tr>
		<tr>
			<td>corticosterone pellet mold</td>
			<td>Ted Pella Inc, Redding, CA, USA</td>
			<td>106A</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse igloo</td>
			<td>VWR, Visalia, CA, USA</td>
			<td>89067-850</td>
			<td>cage enrichment</td>
		</tr>
		<tr>
			<td>peanut butter</td>
			<td>Jif Peanut Butter, Orrville, OH, USA</td>
			<td></td>
			<td>Creamy peanut butter</td>
		</tr>
		<tr>
			<td>pestle and mortar</td>
			<td>VWR, Visalia, CA, USA</td>
			<td>470148-960</td>
			<td></td>
		</tr>
		<tr>
			<td>risperidone</td>
			<td>Patriot Pharmaceuticals, Horsham, PA, USA</td>
			<td>50458-593-50</td>
			<td></td>
		</tr>
		<tr>
			<td>rodent chow</td>
			<td>LabDiet, St. Louis, MO, USA</td>
			<td>5001</td>
			<td></td>
		</tr>
		<tr>
			<td>weigh boat</td>
			<td>VWR, Visalia, CA, USA</td>
			<td>10803-148</td>
			<td></td>
		</tr>
		<tr>
			<td>weighing scale</td>
			<td>Mettler Toledo, Greifensee, Switzerland</td>
			<td>MS104TS</td>
			<td></td>
		</tr>
		<tr>
			<td>Wypall paper X60</td>
			<td>Kimberly-Clark, Corinth, MS, USA</td>
			<td>34865-05</td>
			<td>absorbent paper bedding</td>
		</tr>
	</tbody>
</table>

self-administration of drugs in mouse models of feeding and obesity

Preclinical studies in mice often rely on invasive protocols, such as injections or oral gavage, to deliver drugs. These stressful routes of administration have significant effects on important metabolic parameters including food intake and body weight. Although an attractive option to circumvent this is to compound the drug in rodent food or dissolve it in water, these approaches also have limitations as they are affected by drug stability at room temperature for extended periods of time, the drug's solubility in water, and that the dosing is highly dependent on timing of food or water intake. The constant availability of the drug also limits translational relevance on how drugs are administered to patients. To overcome these limitations, drugs can be mixed with highly palatable food, such as peanut butter, allowing mice to self-administer compounds. Mice reliably and reproducibly consume the drug/peanut butter pellet in a short time frame. This approach facilitates a delivery approach with minimal stress compared with an injection or gavage. This protocol demonstrates the approach of drug preparation, animal acclimatization to placebo delivery, and drug delivery. The implications of this approach are discussed in studies related to timing of drug administration and the circadian rhythm.

In the example presented here, peanut butter was used to deliver risperidone to mice daily for 14 days.
This study shows the chronic delivery of risperidone via this method facilitates highly reproducible increase in food intake and body weight compared with control (Figure 1a,b). In addition, this delivery method results in highly consistent data compared with alternative, more stressful delivery approaches such as intraperitoneal injections (<st...

Watch this Scientific Journal Video about Self-Administration of Drugs in Mouse Models of Feeding and Obesity at JoVE.com

Self-Administration of Drugs in Mouse Models of Feeding and Obesity

The overall goal of this procedure is to describe a method for self-administration of drugs that can be used in mouse models of feeding and obesity.

Preclinical studies in mice often rely on invasive protocols, such as injections or oral gavage, to deliver drugs. These stressful routes of ...

Preclinical studies in mice often rely on invasive drug delivery, such as injections or oral gavage that can have significant effects on food intake and body weight. To overcome these limitations, drugs can be mixed with highly palatable food such as peanut butter, allowing mice to self-administer compounds with minimal stress compared with an injection or a gavage. Begin by pulverizing the drug tablets in a mortar using a pestle.Weigh the calculated amount of peanut butter in a weigh boat on a tared scale. Then, melt it over a beaker of warm water and mix the calculated amount of the pulverized drug into the melted butter. When cooled, place the peanut butter drug mix into a mold.Prepare the placebo pellets with peanut butter alone in a similar fashion. Freeze the mold in 80 degrees Celsius to allow the peanut butter to harden until use. Prepare standard mouse cages with a lining of highly absorbent paper bedding and enrichment, including paper towels and a housing dome.House a single mouse in each cage. Provide ad libitum food and water in the cages, and allow the mice to acclimate to the housing for approximately three days. Before starting the training, fast the mice for 24 hours.On the next day, place a placebo peanut butter pellet as a control on the wall of the cage approximately 1.5 inches from the base. Due to novelty, it may take approximately one hour for the mouse to consume the peanut butter pellet on the first day of a trial. The chronic delivery of risperidone in peanut butter for 14 days facilitated significantly higher daily food intake and more weight gain in C57 black 6 female mice, compared with control.Intraperitoneal delivery of risperidone in the same dosage did not have such robust effects on food intake or weight gain compared to self-delivery in peanut butter. When conducting this protocol, it is important to be consistent with the accuracy of the measurements of food intake, body weight, and the timing of drug administration throughout the study. Future application of this technique include the studies of the timing of drug delivery on food intake and weight gain in the context of circadian rhythm and metabolic health.

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