1. A.5 Neuropharmacology

2. Synaptic Transmission  Remember, neurons communicate chemical signals via a space called a synapse  On one side of the synapse is the presynaptic membrane (of the sending neuron) and on the other side is the postsynaptic membrane (of the receiving neuron)  Kind of like sending an email across this “invisible” space  There are two types of neurons: excitatory and inhibitory

3. Modulation of synaptic transmission  Neurotransmitters are like “doorways” to the neuron  It does not go IN the door, it IS the doorway  It has an effect on the postsynaptic neuron that causes the ion gates to open, causes depolarization or hyperpolarization  Slow vs fast Neurotransmitters  Slow-acting NTs have an effect on the target cell in hundreds of milliseconds or can take up to a minute (dopamine, serotonin, acetylcholine)  Fast-acting NTs have an effect on the target cell within 1 millisecond of binding to a receptor

4. Memory and Learning  Why do we care about fast vs slow NTs?  Slow NTs affect our ability to learn and our memory  Research with slow NTs shows that long-term processes (memory) and short-term processes (learning) differ  Long term (memory): requires the synthesis of proteins, which activate genes in the nucleus, which changes form and function of the synapse, resulting in memory  For a long-term memory to be created, stronger, more longer-lasting stimuli is needed

5. Psychoactive Drugs  Two main neurotransmitters: acetylcholine and noradrenaline  Acetylcholine  Released in all motor neurons  Activates skeletal muscle; parasympathetic nervous system  Depolarizes postsynaptic membrane, but if it remains in synapse, PSM would go on firing indefinitely  To prevent this, an enzyme called acetylcholinesterase breaks down acetylcholine, causes relaxation instead of flight.  Noradrenaline  Also depolarizes postsynaptic neuron; sympathetic nervous system  Causes fight or flight

6. Two types of synapses

7. Causes of Addiction  Why do people take drugs?  Genetic Pre-disposition  Social Factors  Dopamine secretion

8. Between now and Friday: Create an INDIVIDUAL presentation that explains:  What is it? (chemically)  Legal or Illegal?  Effect on behavior?  Cholinergic or adrenergic?  How does it affect the brain and nervous system?  Prevalence of addiction? Long-term use effects?  Treatment of addiction (if necessary) Possible Stimulants and Sedatives: 1.THC – Alexis, Kaleb 2.Cocaine – Marcus, Gabi 3.Alcohol - Celine 4.MDMA - Ruth 5.Nicotine - Rachel 6.Amphetamines - Mithra 7.Benzodiazapines – Dave, Taylor 8.Caffeine - Sara *No more than two people per option. *Sign up with me to claim your spot! Next class: >>Presentations >>Notes over analgesics and endorphins

9. Anesthetics  Block sensory reception of pain at the CNS  Local anesthetics produce drug-induced insensitivity to localized pain  Novocain – local anesthetic that blocks nerve transmission to the pain centers  General anesthetics: volatile compounds that are inhaled, affecting the entire body; results in generalized insensitivity to pain  Used in surgery; causes reversible loss of consciousness

11. Endorphins  Discovered by studying opium addiction  Found receptors for opiates, morphine, heroin in brain cells  These compounds mimic endorphins (CNS neurotransmitters with pain-relieving properties)  Endorphins are:  Released by pituitary gland during stress, injury, exercise  Small peptides that bind to opiate receptors  Endorphins block transmission of impulses involved in pain reception and bind to the receptors involved in pain perception; this blocks the release of neurotransmitters

12. 1.Looking at the labels on the graph, what does “specific binding of” tell you about the number of active receptors? 2.Which group has the highest number of activated serotonin receptors? Give evidence. 3.Compare the data of 0.25 days after the first dose with the data for 1 day after the first dose. 4.What happened to the receptor density over the 21 days following the last dose of MDMA? 5.Explain how MDMA acts on the receptor density of these rats 8 hours after the last dose of MDMA.

13. 1.Which two groups are the “control” rats? Explain why. 2.Compare the other two groups and explain the findings. 3.Draw a conclusion based on these data.

14. Answers 17-21 = 1-5 22-24 = 1-3

15. Next Class:  A.6 Ethology  Review  Exam on Thursday over all of neurobiology  You will receive assignments to complete over Spring Break Thursday: