Safety Considerations
As the activity uses chocolate candies, identify students with this food allergy. Another colored candy may be substituted, and students do not need to eat the candy in order to understand the lesson. Do not conduct this demo in the laboratory, but rather move to an open classroom, hallway, or courtyard. You need a space only about 5m X 5m.

Materials
3 plastic bowls
1 plastic funnel (big enough for M&Ms to pass through)
4 small jars with lids (baby food jars)
~100 green M&Ms
~100 blue M&Ms
~100 yellow M&Ms
3-4 plastic cups
7 students

Management
Estimated Time: 1 hour 30 minutes
Maximum Cost: $25

Procedure
Before you start
Pour blue M&Ms into one of the bowls.
Pour green M&Ms into another one of the bowls.
Fill two jars half-way with yellow M&Ms.

Get Started!
1. Facilitate student review of neurotransmission. (Hit these highlights: Synthetic enzymes for neurotransmitters are made in the cell body, transported to the axon terminal via microtubules, and react with chemical precursors to make neurotransmitters. When an action potential arrives at the terminal, neurotransmitters are released and bind to postsynaptic receptors. Degradative enzymes break down neurotransmitters in the synapse.)

2. Recruit volunteers for the following roles. (Students can make necklace cards or hats with these abbreviations to remind them of their roles.)

Cell Body (CB): Holds blue M&Ms (synthetic enzymes)

Microtubules (M): Transports blue M&Ms (can be more than one)

Axon Terminal (A): Holds yellow M&Ms (precursors)
Releases green M&Ms (serotonin)

Receptor (R): Receives green M&Ms (serotonin)

Action Potential (AP): Triggers green M&M release

Degradative Enzyme (Z): Destroys green M&Ms (serotonin)

MDMA (E, for ecstasy): Gives green M&Ms (serotonin) in mass quantities to R.

3. Facilitate student review of specific duties. (Make diagrams, note cards, or additions to their necklace cards. See Fig. 4.)

4. Places please: Ask volunteers to stand in their places, according to Fig 4. (We have enjoyed placing stage directions on colorful cut-outs on the floor.)

5. Ask other student aides to place props.
a. Place the bowl of blue M&Ms in front of the cell body (Student CB).
b. Give two empty jars to the microtubule student(s) (M).
c. Place the bowl with the green M&Ms and the jars with yellow M&Ms in front of the terminal (A).
d. Place an empty bowl in the hands of degradative enzyme (Z) and ask the receptor (R) to hold the funnel over the bowl.

Let’s Play!
Normal (Drug-Free) Neurotransmission
a. The blue M&Ms in the bowl, held by Student CB, represent the enzymes made by the cell body. The yellow M&Ms in the jars held by Student A, represent the precursors present in the axon terminal.
b. Students M (microtubules) carry enzymes to the axon terminal (Student A) in a jar filled halfway with blue M&Ms (synthetic enzymes).
c. Student M will then pour the blue M&Ms into the jar with yellow M&Ms (precursors).
d. Explain to the students that as the enzymes (blue M&Ms) react with the precursors (yellow M&Ms), the neurotransmitters (green M&Ms) are synthesized. (Just as mixing the colors blue and yellow makes the color green.) Shake the jar with blue and yellow M&Ms to represent synthesis, then place the jar into the bowl with green M&M. Use green M&Ms from here on; serotonin is ready.
e. For a neuron to communicate, an action potential travels from the cell body to axon terminal and signals neurotransmitter release. Student AP (action potential) walks from the cell body (Student CB) to the axon terminal (Student A) and tap Student A on the shoulder. Student A (axon terminal) then takes some green M&Ms and pours them through the funnel held by Student R (receptor). This funnel represents a binding site. The neurotransmitters (green M&Ms) fall through the funnel into a bowl, held by Student Z (degradative enzyme).
f. The degradative enzyme (Student Z) takes the neurotransmitters (green M&Ms) from the bowl and degrades them by eating them (!) or giving them to other students to degrade (eat!). (Alternatively the M&Ms can be placed in a trash receptacle to represent inactivation.)
g. Repeat as often as you like.

Ecstasy is Agony
a. Plan to repeat the sequence again, but this time ask MDMA (Student E) to grab handfuls of green M&Ms (serotonin) from the bowl in front of the axon terminal (Student A) and dump them into the degradation site.
b. Once the bowl with the serotonin (green M&Ms) is empty, the axon is destroyed; Student A sits down. Once Student A sits down, Student(s) M also sit(s) down. These events represent the degradation of the serotonin axon terminal and axon.
c. Ask students whether or not neurotransmission can occur when the axon terminal and axons are destroyed. (The answer is no.)