the brain drugs day 3

You have five minutes to fill in your table of contents and the major concept for today (on the handout.

On the handout for today, fill in the major concept:Drugs affect the biology & chemistry of the brain.

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Date Topic Page19.11.09

Drugs change the way neurons communicate

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www.SummitStudies.com

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By the end of today you will…

Understand that certain drugs interfere selectively with neurotransmission

Realize that the effect of a drug is dependent on the dosage and route of administration.

The plan:

10 min. table of contents & warm up.

20 min. Examine how methamphetamines, nicotine & cocaine disrupt neurotransmitters (animation)

20 min. Compare routes of drug administration (animation)

10 – 12min. Interpret graphical data & answer questions.

3 min. wrap up.

Major Concept

Drugs affect the biology and chemistry of the brain.

Warm Up

What part (hint: system) of the brain regulates pleasure?

Limbic System

Drugs like alcohol, heroin and nicotine excite the dopamine-containing neurons so they produce more action potentials. As the number of action potentials increases, the amount of dopamine __________________________ (increases or decreases).

Drugs Disrupt Neurotransmission

http://science.education.nih.gov/supplements/nih2/Addiction/activities/lesson2_neurotransmission.htm

Let’s see if you are right. Here’s what

happens.. Methamphetamine alters dopamine

neurotransmission in two ways. Methamphetamine enters the neuron by passing directly through nerve cell membranes. It is carried to the nerve cell terminals by transporter molecules that normally carry dopamine or norepinephrine. In the nerve terminal, methamphetamine enters the dopamine- or norepinephrine-containing vesicles and causes the release of neurotransmitter. Methamphetamine also blocks the dopamine transporter from pumping dopamine back into the transmitting neuron. Methamphetamine acts similarly to cocaine in this way.

How is nicotine different from

methamphetamines?

Nicotine…

binds to specific receptors on the presynaptic neuron. When nicotine binds to receptors at the cell body, it excites the neuron so that it fires more action potentials (electrical signals) that move toward the synapse, causing more dopamine release (not shown in figure). When nicotine binds to nicotine receptors at the nerve terminal (shown above), the amount of dopamine released in response to an action potential is increased.

Cocaine

http://science.education.nih.gov/supplements/nih2/Addiction/activities/lesson3_cocaine.htm

What are three ways drugs can affect

neurotransmitters?

1. Drugs can bind at the cell body and send more action potential through the neuron, this increases the amount of dopamine released.

2. Drugs can bind to the terminal end of the presynaptic neuron, releasing more dopamine for each action potential.

3. Drugs can block the dopamine transporter (retake pump) that removes dopamine from the synapse. This results in a rapid rise of dopamine in the synapse. Which leads to feelings of euphoria.

The dose and how it enters into a person’s body, changes the

drug’s effect.

Once a certain amount of the drug enters the bloodstream, a response can then be measured. This point is known as the threshold. As the amount of drug taken increases, so does the response. At higher doses, opiates are toxic and can cause a fatal response by halting respiration.

Drugs enter the body in different ways.

What are four routes of Administration?

Inhalation

Ingestion

Injection

Snorting/Sniffing

And now for something super important

The same amount, or dose, of a drug can lead to milder or more severe responses depending on how the drug enters the body.

http://science.education.nih.gov/supplements/nih2/Addiction/activities/lesson3_pathways-flash.htm

Graphing Practice

Work with a partner to answer the questions on the last page of the packet.

the brain drugs day 3

Education