The Relationship between binge alcohol consumption and the sedative effects of Tetrahydrocannabinol (THC) in F2

progeny of a B6/D2 Mouse Cross Zachary East1, Brandon Frtiz1 and Dr. Stephen Boehm1

1Department of Psychology, Purdue School of Science, IUPUI

Methods

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Introduction

Discussion and Future Directions

There has been considerable interest lately in the combined use of THC And alcohol. In the United States, a handful of states have passed laws making Marijuana Legal for recreational and/or medical use. This experiment will test if there are relationships between the consumption of alcohol and the effects of THC on locomotor sedation. The mice used in this experiment are from a F2 C57BL/6J (B6) x DBA/2J (D2) cross. All of the mice have unique characteristics of B6 and D2 in their genomes. It has been well documented that B6 mice consume more binge like alcohol than D2 mice. One would expect mice with more B6 characteristics to drink more and those with more D2 characteristics to drink less. Also, according to unpublished observations in our lab (Kasten and Boehm, in preparation), it has B6 mice are more sensitive to the locomotor sedative effects of THC than D2 mice. This should mean that mice with more B6 characteristics would drink more and be more sedated by the effects of THC. The experiment is trying to answer these key questions: How do genetics influence binge drinking and THC sedation effects? What is the degree in which the animals are sensitive to both THC and ethanol consumption? Is there cross tolerance between the ethanol and THC and can tolerance occur with repeated ethanol exposure? Is there resistance to drinking and THC and are these two variables related?

Figure 1: Binge drinking data for Group A over a four day period.

Figure 2: Binge drinking data for Group B over a four day period three days after THC injection.

Figure 3: THC locomotor activity: first day was vehicle injection and the second day was an injection of 10 mg/kg THC. Both groups had a similar

sedative response on the second day due to the THC injection.

Figure 4: Group A: Sedation score vs average consumption. According to the correlation statistics the r2 value was around .06. This indicates that

there was no real relationship between consumption and sedation. The slope however is negative and this may mean that this

population of mice has tolerance to the sedative effects of THC due to previous alcohol exposure.

Group B: Sedation score vs average consumption. According to the correlation statistics the r2 value was about .08. This indicates that there was no real relationship between consumption and sedation. However, the slope is positive and this may suggest that consuming more ethanol

might slightly increase THC sedation.

• Overall, there were 76 mice split into two different groups, Group A

and Group B. Each group had half males and half females. All mice

were created from a F2 B6/D2 cross.

• The parental population consisted of an identical heterozygous po

pulation that was bred from inbred homozygote D2 and a

homozygote inbred B6.

• Mice in Group A were placed in separate cages and were left to

habituate to the change in the light/dark schedule and

environment for about three days.

• Next , the mice were all given bottles of 20% alcohol for two hours

in the dark the same time for four days.

• After the four days of drinking, the mice were left undisturbed for

two whole days.

• On the third day all of the mice were weighed and this was used to

determine how much vehicle and 10 mg/kg THC injection they

would receive.

• During first day of injections the mice would receive a vehicle

injection and on the second day they would receive a THC injection.

• After both injections, the locomotor activity of the mice were

measured for two hours.

• Mice in Group B followed a similar procedure except they were

tested for THC sedative effects first, with the drinking second.

• Group B mice were allowed to habituate to the new light/dark cycle

and their environment for three whole days

• On days four and five they were weighed, injected (vehicle on the

first day, and THC on the second day) and their locomotion was

recorded.

• The mice then sat undisturbed for 3 whole days

• The once daily 2 hour drinking protocol was then initiated for the

next four days

• Next the data for the alcohol drinking and THC measurements were

put into a Excel spreadsheet and graphed/analyzed using Graphpad

Prism.

Drinking in the Dark Group A

Drinking in the Dark Group B

THC Locomotor Activity

Average Consumption Group A

Average Consumption Group B Results

There was no significance in the sedation and average consumption correlations between the two groups in this experiment. This could be do to sampling error, which could have resulted from not having a large enough population and the likely hood that some groups may have more B6 or D2 characteristics in their overall populations. Several experimental ones include, accidently providing Group B mice with a higher concentration of alcohol on day 1 of drinking, having two mice taken out of the experiment due to leaky tubes and not being an expert at giving injections. Although there was no significance in the last two Graphs, there seems to be a slight difference between the two groups A and B. Group A seems to be slightly more sedated when increasing alcohol and Group B is the opposite. This could be due to differences in the population genome and/or be due to the different times the two variables alcohol and THC were initiated.

References

Figure 7: Homecage System

Figure 6: Standard Drinking Setup