Midterm 1 Need: ID, Pen, Pencil 25 multiple-choice (50%) –Ch 1,3 2/3 essays (50%) – SQ 1-12

Axon Hillock Biophysics of Neural Impulse: Action Potential Saltatory Conduction: from one node to the next & so on Nodes of Ranvier Membrane- selectively permeable to ions

Ions: 1.Electrostatic pressure 2.Diffusion 3.Na – K “Pumps” Neuron polarized Neuron depolarized Neuron hyperpolarized Proteins--

IPSP - inhibitory postsynaptic potential in Cl - (Chloride) or out K+ (Potassium) The terminals of this axon have inhibitory effects - axosomatic synapse SYNAPSE: The terminals of this axon have excitatory effects Axodendritic synapse EPSP - Na+ excitatory postsynaptic potential

P + P IN OUT Excitation: EPSP axodendritic - Na+ Inhibition: IPSP axosomatic - Cl- in - K+ out EPSP Ionotropic receptor Ion channel Ca++channels open

Types of Receptors: 1. Ionotropic receptor— coupled to ion channel and directly opens it (fast acting). 2. Metabotropic receptor– indirectly opens ion channel (slow acting). It activates G-protein in post-synaptic neuron which (a) opens ion channel, or (b) activates 2 nd messenger (e.g., cyclic AMP) which then opens ion channel (b is more common).

1. Re-uptake or 2.Breakdown Enzyme 3. Autoreceptors Terminating transmission at the synapse:

1. Post-synaptic competition blocking e.g., Thorazin blocks DA receptors 3. Post-synaptic agonist e.g., morphine - Enkephalin, Endorphin valium - GABA 2. Pre-synaptic Reuptake block e.g., Prozac - Serotonin (5-HT) 4. Pre-synaptic agonist e.g., Amphetamine - Norepinephrine No molecule in binding site. Channel closed Transmitter molecule in binding site. Channel is open Drug molecule blocking the binding site. Channel is closed a. Agonists b. Antagonists 1 1 Drugs: Drug (Receptor)