Chemical Messengers

Chemical Messengers

1. Types of Messengers

   • Autocrine
   • paracrine
   • neurotransmitter
   • hormone
   • cytokine
   • neurohormone

2. Transport

   • hydrophilic messenger
     • dissolve easily in plasma so they don't require any type of carrier molecule
     • 3 types Enzyme linked, channel linked, g protein linked
       • Enzyme linked receptor: - hydrophilic messenger binds to the membrane receptor which is connected to an enzyme in the cell ususaly a kinase, activates the enzyme which then brings a response
       • Channel linked receptor- binds to the channel which allows the channel to open so ions or other stuff can move in or out which brings a response
       • G protein- receptor on membrane like to proteins inside the cell, activates alpha subunit and causes it to move, alph goes and works on.
         • a channel protein and causing it to open
         • an ampliphier enzyme, the product is a second messenger (generated in the cell or enters the cytoplasm depending on which one) [ these will be cAMP, cGMP, DAG, IP3]
           • Then a calcium channel could be activated by a first messenger and ca can come in as the 5th second messenger to react with calmodulin and then they go and activate kinase to create a reaction
   • lipophilic messengers
     • 1% dissolved in plasma
     • 99% bound to carrier molecule in the blood
     • go through cell membrane, bind to intracelular receptors, this then binds to the hormone response element at the beginning of a gene, effect transcirption. can be intranuclear. takes time to respond