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Neurotransmitters

Neurotransmitters. AP Psychology. Neurons. Neurons don’t actually touch Separated by a tiny fluid-filled gap called a synapse Neural impulses must be ferried across the synapse by chemical messengers called neurotransmitters. Neurotransmitters.

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Neurotransmitters

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  1. Neurotransmitters AP Psychology

  2. Neurons • Neurons don’t actually touch • Separated by a tiny fluid-filled gap called a synapse • Neural impulses must be ferried across the synapse by chemical messengers called neurotransmitters.

  3. Neurotransmitters • Biochemical substances that are released into the synaptic cleft to stimulate or suppress other neurons. • Dozens of neurotransmitters have been identified.

  4. Each type of (NT) has a three-dimensional shape. • The journey across the synapse takes only a thousandth of a second.

  5. Neuron Potential • Neurons are electrically charged • Resting potential – the state of the neuron when not firing a neural impulse. • Action potential – the release of the neural impulse consisting of a reversal of the electrical charge within the axon. • During this state inside of a neuron is positive and outside is negative. • Allows impulses (messages) to transfer.

  6. Excitatory or Inhibitory • Changes the neurotransmitter makes to the neuron have either an excitatory effect or an inhibitory effect. • Excitatory • Activates the next cell • Makes an action potential more likely to occur in receiving neuron • Hooked to a positive ion channel • Inhibitory • Less likely that the cell will fire • Hooked to a negative ion channel

  7. NT • Some NT have only Excitatory effects • Some NT have only Inhibitory effects • Some NT have both

  8. Preventing the ENT from stimulating a receiving cell • Reuptake: NT not taken up by the receiving cell are reabsorbed by their vesicles to be used again. Nature’s own version of recycling. • Enzymes: organic substances in the synapse break down NT, which are then eliminated from the body in the urine.

  9. How do drugs impact NTs • NT originate in the body • Drugs originate outside of the body. • Antagonists: drugs or chemicals that block the actions of NTs by occupying their receptor sites. • Antagonists prevent transmission of the messages carried by the NT • Compete with NTs at the same receptor sites

  10. How do drugs impact NTs • Agonists: drugs that either increase the availability or effectiveness of NT or mimic their actions.

  11. 5 NT that students need to KNOW • 1. Acetylcholine (ACh): NT that enables motor function in the body. Ex. Wiggle my fingers. • makes muscles contract (motor cortex) • Role in learning and memory. • If ACh transmission is blocked, the muscles cannot contract.

  12. ACh • Underproduction of ACh is an important factor in Alzheimer’s disease • Reductions in ACh weaken or deactivate neural circuitry that stores memories.

  13. ACh • Absence: Paralysis • Oversupply: violent muscle contractions • Certain spider bites/Black widow

  14. 5 NT that Students need to KNOW • 2. Endorphins: natural chemicals released in the brain that have pain-killing and pleasure-inducing effects. Blocks pain. • Inhibitory NT

  15. Endorphins • Located in the Brain, pituitary gland, and spinal cord. • “runners high” • Morphine and heroin are agonists since they mimic the effects of endorphins.

  16. 5 NT that students need to KNOW • 3. Serotonin: affects mood, hunger, temp regulation and sleep. Inhibitory or excitatory • Located in the brain stem, cerebellum, pineal gland, and the spinal cord. • Undersupply may lead to depression, sleeping and eating disorders. • Oversupply linked to OCD

  17. Serotonin • Prozac acts as a agonist • Prozac elevates serotonin levels • Best selling antidepressant! 40 million patients • Some other antidepressant drugs raise serotonin levels

  18. 5 NT That students need to KNOW • 4. Dopamine: influences body movement, learning, attention, reward experiences, and emotion. • Located in the brain and the peripheral nervous system. • excess dopamine receptor activity linked to schizophrenia. • Antipsychotic drugs like Theorize are antagonists that block receptor sites for dopamine.

  19. Dopamine • Parkinson’s Disease: a degenerative brain disease that leads to a progressive loss of motor function. Experience tremors, shakiness, rigidity, and difficulty in walking. • Lack normal levels of dopamine. • Ex. Michael J. Fox • Muhammad Ali

  20. 5 NT that students need to KNOW • 5. Gamma-aminobutyric acid (GABA): a major inhibitory NT. • Regulates nervous activity by preventing neurons from overly exciting their neighbors. • Located in the retina, spinal cord, hypothalamus, and cerebellum. • Exists in as many as a third of all synapses. • Drugs that boost GABA’s effects have a calming or relaxing effect. • Reduced levels of GABA may play a role in emotional disorders in which anxiety is a core feature.

  21. GABA • Alcohol and anti-anxiety drugs like Valium, act as agonists

  22. GABA • Rohypnol (roofies): suppress general neural activity by enhancing the action of GABA. Rohypnol is 10 times more potent than Valium. • Coma, amnesia, respiratory depression, and death.

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