BIO 3153 Lecture Notes - Lecture 17: Neurotransmitter Receptor, Electrochemical Gradient, Signal Transduction
29 Aug 2016
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Document Summary
Cell-surface receptors: 3 major classes of receptor proteins transform an extracellular binding event into an intracellular signal, this is called signal transduction, 1. Ion-channel-linked receptors (extracellular ligand gated ion channels, or ionotropic receptors: receptors that are also ion channels, 2. G-protein-coupled receptors (metabotropic receptors: receptors in the membrane, initiate signaling mechanism controlled by g- proteins, 3. Enzyme-linked receptors (growth factor binding, autophosphorylation: dimerization, broadcast signal through the cell. Ions moving down electrochemical gradients: thus, binding to receptor leads directly to a change in membrane permeability or conductance, and excitability, fast, excitatory. Excitatory or inhibitory chemical synapses: excitatory, activation leads to net gain of positive charge. Sem image of achr: postsynaptic membrane of cell from electric fish, membrane is partially obscured by basal lamina, basic structure of achr can be seen. A nerve impulse reaches the synaptic terminal of a presynaptic neuron causing influx of ca2+ and release of ach into the synaptic cleft.
