Pharmacology

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Ligand-gated Ion channels: 

·         Fastest response; used in neurotransmission.

·         Binding of neurotransmitter causes opening of the channel's pore to ions; the cell depolarises (excitation) or hyperpolarises (inhibition).

·         Cellular response results from the change in membrane potential, or from the change in intracellular ionic concentration.

·         EXAMPLES: Nicotinic superfamily, glutamate superfamily, purinergic superfamily (ATP).

G-Protein Coupled Receptors:  

·         These are slower than the ligand-gated receptors and allow slower neurotransmission.

·         Process of signal transduction: 

o    The G-protein trimer is bound to GDP.

o    The agonist occupied receptor binds to the G-protein and GDP is exchanged for GTP. The trimer dissociates to α (which is bound to the GTP) and βγ.

o    The α and βγ subunits reach and activate or inhibit effectors. 

o   

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