Psyc4130 1nd Edition Lecture 5 Outline of Last Lecture I. Blood Brain BarrierII. Important terms/conceptsA. Action PotentialB. Phospholipid III. Three PotentialsA. Resting potentialB. Graded potentialC. Action potentialOutline of Current Lecture I. Ligand-gated ion channelII. Ligand-gated Chloride channelIII. EPSPIV. IPSPV. Nodes of RanvierVI. ExocytosisVII. SynapseVIII. Post-synaptic ReceptorsIX. DiffusionX. Terminating TransmissionCurrent Lecture(Note: Professor did not have PowerPoint reference today- lecture was sporatic)- Ligand-gated ion channelo 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 channelo 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…)- EPSPo Excitatory Post-Synaptic Potentialso Transient depolarizationo Must sum in order to reach the threshold of excitation and thus cause the neuron to fire- IPSPo Inhibitory Post-Synaptic Potentialo Hyperpolarization- Nodes of Ranvier o Contains more voltage gated sodium channels- purpose is to recharge the action potential throughout the length of the axono Axon potential jumps from node to nodeo Saltatory conduction- only for mylenaited axons (jumping)- Action Potential Initiation of Exocytosiso 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.- Synapseo Where drugs work, they modify some element of the neurotransmission processo Lots of mitochondria in axon terminal o Omega: fusing of the synaptic vesicleo Neurotransmitter like serotonin (key that goes into lock, but don’t carry it into room) just actives receptor and job is done - Post synaptic receptorso Two major classesIonotropic 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 - Diffusiono Can slowly terminate the activity of post synaptic receptors However you want it to be quick and terminate it quickly… (see below)- Terminating Transmissiono Enzymatic degradation/inactivation Creates enzymes that binds o Removal aka Reuptake Vacuum cleaner, terminates neurotransmission Cocaine: binds to transporters and blocks them, reuptake
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