Psyc4130 1nd Edition Lecture 5 Outline of Last Lecture I Blood Brain Barrier II Important terms concepts A Action Potential B Phospholipid III Three Potentials A Resting potential B Graded potential C Action potential Outline of Current Lecture I Ligand gated ion channel II Ligand gated Chloride channel III EPSP IV IPSP V Nodes of Ranvier VI Exocytosis VII Synapse VIII Post synaptic Receptors IX Diffusion X Terminating Transmission Current Lecture Note Professor did not have PowerPoint reference today lecture was sporatic Ligand gated ion channel o i e sodium channels NA o Cause depolarizing currents which are excitatory o When sodium comes in you lose polarity depolarizing current o Starting out 70 and adding pluses moving in direction of zero Ligand gated Chloride channel o When they are open they are going to selectively allow chloride ions to infiltrate the neuron IPSP inhibitory These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Hyperpolarization 70 71 moving farther away from zero Ligand meaning opened up by ligands drugs etc EPSP o Excitatory Post Synaptic Potentials o Transient depolarization o Must sum in order to reach the threshold of excitation and thus cause the neuron to fire IPSP o Inhibitory Post Synaptic Potential o Hyperpolarization Nodes of Ranvier o Contains more voltage gated sodium channels purpose is to recharge the action potential throughout the length of the axon o Axon potential jumps from node to node o Saltatory conduction only for mylenaited axons jumping Action Potential Initiation of Exocytosis o Exocytosis CA2 rising calcium concentrations in the axon terminal Release of cellular products into the ECF by the docking of vesicles with cell membrane Axon Terminals Voltage Gated Ca Channels Synaptic Vesicles Calcium influx activates a protein called CaM kinase II which initiates exocytosis Synapse o Where drugs work they modify some element of the neurotransmission process o Lots of mitochondria in axon terminal o Omega fusing of the synaptic vesicle o Neurotransmitter like serotonin key that goes into lock but don t carry it into room just actives receptor and job is done Post synaptic receptors o Two major classes Ionotropic receptors The ion channel opens when a molecule of neurotransmitters attaches to the binding site GABAA benzodiazepine ligand gated chloride channel closes when GABA or drug opens it up and allows chloride to enter and causes neuroexcitation sedation causes more chloride to come into cell behavioral sedation Ethanol Metabotropic Receptors More sophisticated neurotransmitter binds and kickstarts a cascade of biochemical reactions inside of post synaptic cell that either excites inhibits it indirectly Outnumber ionotropic receptors in the brain Second messengers kickstarts events to occur in the cell Diffusion o Can slowly terminate the activity of post synaptic receptors However you want it to be quick and terminate it quickly see below Terminating Transmission o Enzymatic degradation inactivation Creates enzymes that binds o Removal aka Reuptake Vacuum cleaner terminates neurotransmission Cocaine binds to transporters and blocks them reuptake inhibitor
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