Open Field Test
Week 2 June 22-June 26, 2015
A major part of this week was spent on continued behavioral testing of the 32 rats previously tested in the Von Frey and observational tests. We did the Open Field and Elevated Plus Maze tests that assess the anxiety of the rats.
The Open Field test consists of putting a rat in semi-large, black, square box that is marked with a white grid. The box is set under a camera that records the movement of the rat when it is placed into the box for ten minutes. It is important that little to no noise be made that may cause the rat’s movement to be disrupted by outside interference. Later on, the film of each rat will be put into a program that records and marks down how many times the rat moves into the middle of the box and the time it spends in the middle of the box and closer to the edges.
The expected outcome is that the rats on high doses of nicotine will have more anxiety and thus spend less time in the center parts of the box. In addition, as the dosage decreases with each lab group, and eventually the naive and control are exposed to none, their anxiety will decrease and they will be shown to walk out in the open center of the box more often and for longer period of times.
In the Elevated Plus Maze test each rat is first placed in the center of the maze. The maze is simply a plus sign with two opposite arms having walls and the other two opposite arms begin exposed. The rats are observed for five minutes each. A mark is recorded each time they enter one of the arms, and only marked if it is a different arm than the one they had just left. In addition, we timed when they were out in the open arms and recorded that data. As previously stated, the rats on high dosages of nicotine should spend more time in the closed arms and less time moving about, while the non-nicotine exposed rats should spend more time in the open arms and moving about between the arms.
Elevated Plus Maze
On Thursday and Friday we made catheters for the nicotine vapor chamber rats, Marsida’s second rat experiment. The catheters consist of tubing and a metal pipe surrounded in a plastic consistency substance. One side of the catheter is hooked up to a piece of tubing that is connected to the syringe with nicotine in it, while the other side has tubing that goes into the animal’s right jugular vein. When the animal presses the lever the drug will be administered, flowing through the tubing and into the bloodstream giving the rat the drug and feelings of reward it was craving. The catheters will be surgically implanted into the rats.
On Thursday we also went to see a presentation by Dr. Eisuke Koya, from the University of Sussex and National Institute of Drug Abuse (NIDA). He talked about his research in terms of memory affiliation with taking drugs and location (Context-induced relapse to drug seeking: a review). This study has been done previously, so he was confirming the results and then looking into new areas for future possible experiments. The experiment showed that when the rat was administered the drug in place A, taken out and put through withdrawal, then replaced in place A and given the drug, more C-Fos was released compared to the rats placed in place A at first and given the drug, withdrawn, and then placed in place B and given the drug.
This shows that when a drug is taken, the memory links up the situation, location, etc., with the feelings and reward of the drug taken. Thus, when the same situation is encountered later on, the rats start to crave the drug and have a higher chance of taking it. This is one problem commonly faced by recovering addicts.
Dr. Koya also observed the effect of Daun02 (Targeted disruption of cocaine-activated accumbens neurons prevents context-specific sensitization) when administered within the brain. The results showed that it did indeed completely erase the affiliation between a location and the administration of the drug, decreasing the chances of craving and taking the drug when the same situation is encountered. The George Lab is also looking into the possible uses and workings of Daun02, making this presentation of interest to Giordano and Olivier.
Over the next few weeks we are also starting to compile photos, often taken by Marsida, and the numerous amounts of information thrown at us to put together a PowerPoint that we will present at the end of our internship on Friday, July 24th. Although it is difficult to digest all the scientific content we see and hear, this experience has been incredible and has helped me better understand the working of alcohol, nicotine, and such other drugs that are so prevalent in my life as a teen and living in Colorado.
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