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Neurotransmitters. What is a neurotransmitter? A chemical secreted by an axon. Watch video Excitatory neurotransmitters - lead to changes that generate an action potential in the postsynaptic neuron Inhibitory neurotransmitters
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Neurotransmitters What is a neurotransmitter? A chemical secreted by an axon. Watch video • Excitatory neurotransmitters - lead to changes that generate an action potential in the postsynaptic neuron • Inhibitory neurotransmitters - tend to block the changes that cause an action potential to be generated in a postsynaptic neuron
Watch an animation on neurotransmitters What ion causes the release of neurotransmitters from the axon terminal? Calcium
What ion channel will be opened during excitatory response? Sodium (ions will rush into the postsynaptic neuron causing an action potential) What ion channel will be opened during inhibitory response? Chlorine (ions will rush into the postsynaptic neuron making the inside of the cell more negative therefore no action potential)
What happens if both excitatory and inhibitory signals are sent? The impulses are summated and the greatest type is carried out. “ALL OR NOTHING RESPONSE” What happens to the neurotransmitters after they have fused with the postsynaptic receptor? Broken down by enzymes or they reenter the presynaptic axon terminal
Excitatory neurotransmitters Acetylcholine Glutamate Epinephrine Serotonin Sleepiness, mood Activates muscles Learning and memory Also called adrenaline, keeps you alert and mentally focused
Inhibitory Neurotransmitters Endorphins Dopamine GABA Calms the brain, controls anxiety Reduce pain and increase pleasure Motivation and pleasure, known for its role in addiction
Glutamate: The most common and most potent excitatory neurotransmitter in the CNS GABA and glycine: The major inhibitory neurotransmitters in the CNS. Acetylcholine and norepinephrine are the most important neurotransmitters in the PNS.
Effect of drugs on neurotransmission When neurons do not communicate normally, the brain does not function normally either. Cocaine How does cocaine affect neurotransmission? Why are many drugs addictive? -Tolerance -Withdrawal Mouse Party Interactive On-line Activity How does marijuana affect neurotransmission? Summary- Rats on Drugs
Determine what happens when 2 drugs are mixed Caffeine (disrupts adenosine) Alcohol (disrupts GABA) Link to example Open “Effect of Drugs on Neurotransmission” Complete by 7pm tonight