BIOM20001 Lecture 40: 40 Cell Communication III C
Document Summary
Short stature, obese, round face, subcutaneous ossifications, characteristic shortening and widening of long bonds in the hands and feet, resistance to various hormones (tsh, pth, vasopressin, gonadotropin, prolactin and glucagon) The gland and the hormone are fine but the cell response is not. Activated beta-gamma subunits can also bind to a target protein and activate them. In heart muscle acetylcholine can bind g-protein-linked receptor. Activated beta-gamma subunit binds to a k+ channel and opens it. Loss of k+ ions reduces contraction and heart rate. After alpha is inactivated it reassociates with beta and gamma subunits and the k+ channels closes. Pathways involving opening of ion channels are very quick e. g. g protein -linked receptors involved in. Smell receptors activated by food and stimulation of saliva. Fastest is the response of photoreceptors to light. When inactive the cell is depolarised and cation channels are open. Light induced isomerisation of cis-retinal (cis-->trans) causes conformational change in rhodopsin.
