Day 11

Microinjections

Today, we are testing rats in group C.  This morning, I came in and prepared the syringes for microinjections.  I cleaned the fragile microinjectors with ethanol and distilled water.  I then filled them with water and attached them to the pump.  I also prepared the tubes for microinjections.  After I vortexed the drugs, we began microinjections for group C2.  All rats received 0.01M quinine (bitter).  All aCSF injections went well.  The first rat receiving CDP had problems with the left side.  It took three microinjections for the air bubble to move on the left side.  The second rat also had trouble, and when I reinserted his dummy into his right cannula, liquid was coming out.  Group C3 rats all received 0.01M quinine except for the rat in Box 4 who received 0.03M NaCl.  Group C1 rats all received 0.01M quinine.  We gave water to group D rats for 60 minutes, and agitated the cannulae of and weighted rats in group A and group B.  I discovered that rats can unscrew their dummy if it is not properly secured.  When agitating one cannula of a rat, his was missing for the second time because he had methodically taken it out.

CTA Testing

Dr. Holstein taught us how to prepare syringes for CTA (conditioned taste aversion) testing.  First, you take the barrel and move the plunger in and out a few times in the LiCl to get rid of air bubbles. Then you hit the barrel against your hand to move the air bubbles to the top.  After they are at the surface, you pull back on the plunger so there is air in the barrel and push the plunger back in until liquid comes out.  You can then screw on the needle tightly, pop off the cap, and squirt the liquid out of the needle.  We prepared 16 syringes with LiCl to inject group A and group B rats with.  The LiCl was injected to the left or right of the midline about an inch above the base of the tail.  It is important to pull back on the plunger when injecting the rats to make sure no blood is coming out.  LiCl will make the rats feel sick, which we hope they will associate with the NaCl they are given to drink (rats in group A and group B had not been given NaCl before, so it is a new taste for them).  Julia and I did not yet experience CTA testing, but will have that opportunity when it is time for the rats in group C and group D.