BIOLOGY 3P03 Lecture Notes - Lecture 17: Adenylyl Cyclase, Protein Kinase, Neurosecretion
28 Dec 2017
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Document Summary
Also known as the dihydropyridine channel (dhp channel) Like most voltage-gated ion channels has -subunit composed of four subunits- Each subunit is formed by six -helical, transmembrane domains that cross membrane (s1-s6: s1-s4 subunits are voltage-gated speci cally (i. e. voltage sensors)- the other two allow for selectivity of channel (i. e. selectivity lter) L = long-lasting (referring to length of activation) Responsible for excitation-contraction coupling of skeletal, smooth, and cardiac muscle. In cardiac myocytes l-type calcium channel passes inward calcium current and triggers calcium release from sr by activating ryanodine receptor 2 (ryr2) (cicr)- Phosphorylation of these channels increases their permeability to calcium and increases the contractility of their respective cardiac myocytes. When cell depolarized, it opened channel which allowed very small amount of calcium to enter cell- f/f0 is the di erence in uorescence which was seen when this small amount of calcium entered the cell. Fluorescence signal corresponds to calcium concentration of a single calcium channel in heart cell.
