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PGY 451 CELLULAR NEUROSCIENCE EXAM 1 REVIEWTOPIC 1 In a typical cell, there is a higher concentration of potassium inside the cell and a smallerconcentration of potassium outside for cell. As a chemical, it wants to go outside but as acharge, it wants to stay inside because the inside is negative. For sodium, there is a larger concentration outside the cell and a smaller concentration inside of the cell The sodium- potassium ATPase pump ensures you have this uneven distribution of ions. Can store information Information= energy Any uneven distribution of anything will store energy. Use NERNST EQUATION to describe anything with an uneven distribution Rest membrane potential for a typical cell is -70 mV and the outside is 0 because you aregrounded. The resting membrane potential for a muscle cell is -90mV EXAMPE: Let’s say you have ENa=66 mV and Ek=−91 mV and your RMP=-70mV. If you had a sodium channel and a potassium channel, a lot of the sodium would want tocome into the cell because it has a greater driving force. Only a little bit of the potassiumhowever would want to leave the cell, this value isn’t as large because the driving force isn’t that big. At the peak of the action potential, the potassium will come out because the channel will be open and this will result in a drop in the Vm. K+ has a huge reason to go out at the peak of an action potential because 0 is closer to negative than a 50. This is why there is a rapid decrease in an action potential graph Vm will drop quickly because of 2 reasons:1. No longer have supply of positive charge from the outside2. K+ is leaving the charge, you are losing positive charge Action potentials will not degrade because they will always regenerate KEY TERMS- K+ greater inside cell- Na+ greater outside cell- 2 K+ in, 3 Na+ out- Nernst equation used for uneven distribution (to describe energy)- Typical neuron RMP= -70mV- Muscle cell RMP= -90 mV- At -50, the sodium channel becomes inactivated.- Vm on an action potential graph will drop quickly because there’s no more positive charge being supplied and because you’re losing positive chargeTOPIC 2 At the axon hillock in a neuron, you want to generate an action potential. The axon hillock is the axon (the long part) Encode information in the frequency Vesicle will fuse with plasma membrane so the content will come out. An action potential causes neurotransmitter release by calcium sensor and SNARE protein that holds the vesicle to the active zone waiting for the calcium sensor. The calcium is able to come in because you have VGCC- Voltage gated calcium channel. Calcium causes the vesicle to fuse.  The purpose or action potential is to cause neurotransmitter release  Neurotransmitter release is caused by the fusion of the vesicle with the membrane. The inside of the vesicle is very concentrated, it is 150 mV. The outside is 0 so it will just rush out Neurotransmitter will release into the synaptic cleft where there are a lot of receptors. Once it binds, the neuron can now act on the post synaptic neuron Ionotropic receptor- channel for ion to directly come in, not like a hole. Can be different ion depending on the neurotransmitter Metabotropic receptor- is a GCPR. Have to let the neurotransmitter bind to it. The GCPR will have a G- protein and the G-protein will activate the signal transduction pathway.  The signal transduction pathway can affect the ionotropic channel such as the sodium channel, the potassium channel… Glutamate can have two receptors—the ionotropic or the metabotropic.1. Glutamate as ionotropic receptors: AMDA, NMDA, Kainate2. Glutamate as metabotropic receptors: mGluR 1-8 GABA has two receptors- ionotropic or metabotropic1. GABA as ionotropic receptors: GABA a, Gaba c2. GABA as metabotropic: GABA bKEY TERMS- Axon hillocks- action potential occurs- Frequency in action potential- Vesicle fuse to membraneneurotransmitter released go to synaptic cleftbind to receptor- VGCC: voltage- gated calcium channel- Ionotropic- channel- Metabotropic- GCPR’sTOPIC 3 There are excitatory neurotransmitters and inhibitory neurotransmitters Whether they are excitatory or inhibitory depends on the receptor. With the excitatory neurotransmitters: glutamate and Ach Inhibitory: Gaba and glycine Modulatory neurotransmitter can be the same. Can be excitatory or inhibitory.- For example: when the GABA B receptor (GPCR), it will be modulatory either inhibitory or excitatory. It depends on the signaling pathway, the neurons it is working. Dopamine and serotonin and the rest of neurotransmitters are all G- protein coupled receptors except for 5-HT3 5- HT3 is a ligand gated channel that is gated by serotonin. Cocaine blocks the reuptake of dopamine from the dopamine transporter which makes the action prolonged and the subject will experience a high. Transporters are used for reuptake back into the pre-synaptic cell. SerT is the serotonin transporter SerT is responsible for taking back serotonin. People with depression will take an antidepressant like Prozac. Prozac will block the serotonin transporter so serotonin in the synaptic cleft can increase and the action can be prolonged and that can stabilize themood. If the vM goes beyond the threshold, you will generate an action potential Can have transporters for reuptake on the presynaptic cells or the glial cells or the post synaptic cells. REUPTAKE DOES NOT APPLY FOR Ach!! IT IS DEGRADED INTO CHOLINE AND THEN THE CHOLINE CAN GET TAKEN BACK FOR REUPTAKE. 2 other type of neurotransmitter: Gas and neuropeptide. Reuptake does not occur for those!! Gas can only go away by diffusion. Same is true for the neuropeptide; it can only be diffused out or degraded.KEY TERMS- Excitatory- glutamate and Ach- Inhibitory- GABA and Glycerin- Modulatory- either excitatory or inhibitory- 5-HT3 gated by Serotonin- Cocaine blocks the reuptake of dopamine. More dopamine= More happy- Prozac used as antidepressant. Blocks serotonin transporter to stay in synapse.- Release and reuptake are two different things- Transporter is responsible for reuptake- Reuptake of choline from Ach. No reuptake of Ach- 2 other neurotransmitters: Gases & Neuropeptide- no reuptake for both.TOPIC 4 A large axon (length) has a higher conduction velocity. It has to do with the decay. Anything that has charge will decay.  AP appears like they don’t decay but

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