Cocaine

Cocaine Professional Development:
cocaine lab description:

Kinks in the Cocaine Lab:
 * Using back button sometimes kicks you out of the program (I used the help button, and got kicked out when I used the browswer's (Firefox) back button)
 * Students can copy and paste from text in the desk area, into their lab notebook, are we ok with that?
 * Task in the prep area: "calculate anesthesia" How? It says in the notebook, which is fine. But since we get a prompt later during the prep area, why have it so early on the list? I thought I was supposed to enter it then (not later) and got "stuck" for a few minutes, before I realized I could put the needle and vile on the right hand side of the prep area.

**Prep Desk Guide:**

**Prerequisite:** Before doing anything at the prep desk area, students should have been to the desk area, done their reading filling out their lab notebook. Specifically, students will need to know how to calculate how much anesthesia to give the rat. (1 ml/kg) The weight of the rat will be given to student in grams. So students must be able to convert grams to kilograms. Example calculation: 1 mL/kg x 200g (rat)/1 x 1 kg/1000g = 0.2 mL You may want to do some sample conversions if students have not done these before. You could also suggest that they show their work in their lab notebook to make sure they understand the concept.


 * Overview:** Students will select a rat, determine how much anesthesia to administer based on the rat's weight, administer the anesthesia via syringe, and clean up the lab area.

1) Read sticky note from advisor (students will refer to this throughout this section) 2) Put on gloves 3) Select rat (they pick either a female or male rat), weigh it, calculate amount of anesthesia, and then place the rat in the prep tray. 4) Place syringe and anesthesia bottle in prep tray. 5) Extract the correct amount of anesthesia (0.3 ml for female rat, and 0.35 ml for male rat) 6) Inject anesthesia in the correct location on the rat. 7) Dispose of the syringe & put bottle away.
 * Specific Tasks** students will be asked to complete at the prep desk:

While the advisor's note tell students to calculate the weight of the rat in the third task, students don't actually need to do anything with that number until they fill the syringe a few tasks later.
 * Special notes:**

Remind students that their lab notebook answers are important because they will be using those later in the lab to answer questions that will help them get "published." They will have full access to their notes as they answer a series of questions after they have completed the experiment and collected data.

**Surgery Guide:** Overview: In this section, the student will insert electrodes into the rat’s brain in order to monitor dopamine levels during cocaine self-administration. Special Notes: The students must wear full gear (mask, gloves, and lab coat) in order to prevent infection in the rat. Betadine is also applied to the surgery area for this reason. Intrajugular cocaine injection is the most efficient way to deliver cocaine to the rat. The stereotaxic apparatus does not harm the rat and ensures that all electrodes are inserted in the proper places. The rat is secured in the apparatus by both a nose/upper jaw clip and ear bars. Cutting the muscle and skin is a little more tedious than displayed. These tissue layers are held together by connective tissue that needs to be scraped away from the surgery site. The reference electrode acts as a chemical “control”, stabilizing the brain’s environment so the other electrodes can work properly. The sensing electrode is placed in the striatum of the rat where the dopamine neurons from the substantia nigra terminate. This is where the best measure of dopamine release can be found. (?????? Why is the sensing electrode in the nucleus accumbens versus the CP???????) The stimulating electrode delivers voltage to the axons of the dopamine neurons. This stimulates the neurons to activate dopamine release. (?????Why is the stimulating electrode necessary when the rat is actually doing the stimulating in order to get cocaine??????? Why the ventral tegmental???) The rat is on a heating pad during the surgery and recuperation because, while under anesthesia, it can not maintain its own body heat. The cap and cement hold all the electrodes in place, allowing for the measure of dopamine release and stimulation of the dopamine neurons while the rat moves around.

Possible Questions:
 * 1) Why is the sensing electrode placed in the nucleus accumbens?
 * 2) Why is the stimulating electrode placed in the ventral tegmental?
 * 3) Explain what the rat needs to be on a heating pad during the surgery and recovery times.

**Experiment Guide:** Overview: In the experiment portion of the lab, students will observe the rat’s dopamine levels as it self-administers cocaine. Since cocaine produces a release of dopamine in the brain, one would expect to find an increase in dopamine only after the rat presses the bar. According to this experiment, however, the dopamine spikes as the rat approaches the bar to press it. This would indicate that dopamine if involved in the anticipation of actions and may give further insight into drug addiction. Possible Questions:
 * 1) Describe the dopamine activity in the rat’s brain during the experiment. What was occurring when it went up? What was occurring when it went down?
 * 2) Interpret these results in light of what you read about how animals behave. What stage(s) of behavior does dopamine appear to be involved with? Explain your answer.
 * 3) Explain how these results might help researchers in the area of drug addiction and other behaviors.