Monday, July 8, 2013

Phase III: Day 1 - Training

Today was the first day of training for the phase III test rats. During this phase we subjected the test animals to fifteen trials in the Davis Rigs in order to train the animals to lick while in the rigs. Each rig contained three bottles containing water, 2 millimolar sucrose, and 2 millimolar glucose.

Each of the twelve rats were trained today, and each of them licked for 50-70% of the trials. We have three more training days to get these rats to lick for each of the trials.

- Deep

Sunday, July 7, 2013

Summary of Phase II

Apologizes for not updating this blog more often. Phase II of the experiment has just been completed, and Phase III will begin starting tomorrow. Now that this phase is complete let's see what we did and accomplished.

Step 1: The rats were trained. Training the rats is essentially putting the rats into the Davis Rigs, a device designed to precisely count the number of licks a rat does at any given trial. The training period is used to teach the rats they when they are inside the rig they are expected to lick. This will give us better data later on when the actual taste trials are conducted. The rats are given water and 0.2 molar sucrose solution and placed in the rigs over 30 trials. These training days lasted about four days to ensure the test rats will be properly trained.

Step 2: Surgery. The anti-anxiety drug must be injected into a particular region of the rat's brain. In order to inject the drug the test rats must undergo brain surgery in order to place the cannulas into the rats' brains. The process requires a small incision down the top of the rats head. The area is cleaned to reveal the top of the rat's skull. Using a measuring tool the rat's skull is properly aligned so that the cannulas can be placed into the appropriate region of the rat's brain. After that 6 holes are drilled into the skull, two at the cannula sites and four closer to the rats eyes to hold the screws. Next, a single cannula is placed into the rat's brain and cement is placed in order to keep the cannula in place. Next the second cannula is placed into the rat's brain, and once the cement is completely dry the rat is left to recover for a couple of days.

Step 3: Taste Trials. Once the rats have recovered the actual taste trials can be conducted. The rats have either the drug or a control substance (cerebral spinal fluid) injected into their brains. Once the appropriate substance has been injected the rats are placed in the Davis rigs for the trial. The rats are given aqueous solutions containing various concentrations of sodium chloride, quinine, and citric acid in order to test salty, bitter, and sour tastes. The rats under go four trials over the course of a week and a half in order to get proper data.

Step 4: Perfusion. Once the trials are complete the rats must be perfused and the brains must be removed in order to do proper histology on the rats. Formalin is injected into the rat in order to replace the blood and preserve the brain. Once the brain is removed it is placed in a formalin solution and preserved in a chilled environment.

That is the summary of phase II. I'll give you more frequent updates on Phase III, the final phase for this summer.

- Deep Sangani