PSL300H1 Chapter 6: Chapter 6 Metabotropic Receptors
Document Summary
Many receptors catalyze enzyme reaction rather than directly changing ionic perm abilities. They increase production of second messengers, camp, cgmp or inositol triphosphate (inp3) which then initiate secondary metabolic effects. Metabolic receptors activate enzymes which catalyze production of a second messenger. The chemical agents used for synaptic transmission are all amino acids, peptides, or amino acid derivatives. The receptor determines the ionotropic or metabotropic action of a transmitter. Receptors for noradrenaline come in two classes: and , which are g-protein. 1 activates adenylyl cyclase, and are found in cardiac muscle. 2 is found in smooth muscle where they cause vasodilation. G-protein structure secondarily activates adenylyl cyclase, increasing the concentration of camp, catalyzing the phosphorylation of membrane proteins and ca++ channel. Some ion channels are gated open by second messenger molecules produced as a result of metabotropic activity. They are removed by transporters or enzymatic degradation ach is hydrolyzed by acetylcholinesterase. Products are reabsorbed by pre or post-synaptic cell.
