Summer Students 2006

Greg Hogate studied ethanol conditioned place preference in C57 wild type mice. Mice were injected with either saline or 2g/kg ethanol and placed in one side of a 3-compartment activity box for 10 minutes. The right and left compartments had different walls floors and smells; each was randomly paired with either an ethanol or a saline injection for each mouse. In his study Greg examined whether an acetaminophen (Tylenol) injection given after conditioning sessions would strengthen the mice’s preference for the ethanol-paired side of the activity box. Mice that were initially given saline were injected with the acetaminophen vehicle. After ten conditioning sessions the mice were placed in the center of the conditioning box, and a computer measured how long the mice stayed in each compartment. The mice displayed a fairly strong preference for the ethanol paired compartments.

Jennifer Porth is a rising senior Psychology major who worked in the Neuroscience Lab this summer. She studied the self-administration of alcohol during two hour periods in different strains of mice with varying levels of beta-endorphin. Mice initially received alcohol mixed with sucrose until receiving 15 % alcohol through after an 8 day fading procedure. To represent the experience of a natural stressor, mice underwent the forced-swim test. Alcohol consumption was once again measured to study the drinking patterns before and after stress. Heterozygotes- mice that have only half the normal amount of beta-endorphin- are expected to demonstrate high alcohol consumption that further increases after stress in order to compensate for their deficiency. Data analysis is still in progress to determine actual experimental results.

 
Julie Usala, a rising junior majoring in Neuroscience, studied the effect of α-MSH (melanocyte stimulating hormone) on the social interactions of male and female Swiss Webster mice. A pair of naive female and male mice were first exposed to each other in a social interaction box twenty minutes after an ICV injection of either α-MSH or saline. the pair remained in the box for ten minutes, during which they were measured on the following behaviors: line crosses, flees, tail follows, frontal investigations, anogenital investigations, self-grooming, rears, mounting, initiate contact, and squeaks. based on previous research, it was hypothesized that α-MSH males would decrease in social behaviors compared to their saline counterparts. In addition, the impact of female estrous cycle on social behaviors and the drug's effects were also examined. Estrous cycle was determined by subtle changes in vaginal appearance. It was predicted that α-MSH mice in proestrus or estrus would have increased social behaviors compared to α-MSH males have decreased social behaviors compared to the saline groups. however, it appears that α_MSH, nonestrus mice have fore social behaviors that α-MSh, estrus mice. A second trial with a different strain, MC1R (melanocortin 1-receptor gene), is still in progress.

Kevin Karwan is a junior neuroscience major at Furman University. His main study was to test a new compound of Lidocaine against the form already in use. The new compound, called Lidocaine Docusate, is an ionic compound that is supposed to be more effective than the already used form of Lidocaine HCl. The two compounds were mixed with DMSO to form a topical anesthetic. Mice were given a mild injury and then one of the compounds was applied. Then the mice were tested for pain sensitivity using the tail-flicks method. Kevin also worked with Sidney Williams on her study of ethanol consumption in beta endorphin knockout and heterozygous mice. He also worked with Alex Woodell on his study of endorphin-ethanol relationships in regular and b-endorphin KO heterozygous mice.

Liana Matson, a rising sophomore majoring in Neuroscience, studied the effects of α-MSH (melanocyte stiumulating hormone) on the social interaction between male and female Swiss Webster. Additionally, the state of the estrous cycle of each female was taken into account for the ppurpose of determining whether MSH has a larger effect during estrus or aestrus. The female mice were determined to be in estrus or aestrus visually and then assigned a male partner. Each member of the pair was then injected with either saline or MSH, and the pair was placed in an interaction box for ten minutes. The degree of social interaction between the pair was then evaluated using ten different measures of behavior: line crosses, tail follows, flees, anogenital investigation, frontal investigation, rears, speaks, self-grooming, mounting, and initiate contact. Although results are presently pending, the preliminary data suggests that α-MSH may have the greatest bahvior increasing effect on aestrus feamles and an opposite effect on the male Swiss Webster mice. Hence,α-MSH could possibly be untilized in increasing the social interaction of female mice.

 

Ashley Holloway is a USC biology student that worked in the Neuroscience Lab this summer.  She studied the self administration of ethanol in ovariectomized and non-ovariectomized female mice.  Each mouse underwent surgery; either ovariectomized (OVX) or not ovariectomized (sham).  After the allotted time for hormone depletion, the mice were given five concentrations of ethanol, each concentration for four days.  Consumption, preference and dosage were read and recorded daily.  The study showed no significant difference in overall preference and dosage between the two groups.  Ashley also studied the interaction between sex hormones and beta-endorphin and their affect on alcohol sensitivity by measuring loss of righting reflex after ethanol injection.

 

Alex Woodell is a senior Neuroscience major who studied the interactive effects of ethanol and stress on beta endorphin levels. This study used beta endorphin knockout heterozygote mice as a model for alcoholics, comparing them to C57BL/6J controls. On day 1, mice were injected with saline or ethanol and placed in a light/dark box for baseline measures of anxiety. On day 2, mice were injected with drug based on a crossover design and stressed via the tail suspension test, followed by testing in the light/dark box. Blood samples were taken on both days via the orbital sinus cavity and plasma was extracted. Blood ethanol concentration was measured using aliquots from each sample and plasma beta endorphin levels were obtained by using a commercial radioimmunoassay kit. This study was designed to determine 1) a possible link between beta endorphin and alcoholism and 2) the effects of stress and ethanol on beta endorphin levels.

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