Essential Pharmacology 1 Flashcards
What can be chemical messengers?
- Hormones
- Neurotransmitters
How can variety of responses in receptors be brought about?
- One cell can have receptors for many different chemical signals
- One cell can have several different receptors for the same chemical signal so that it triggers several different responses
What can receptors do?
They make an appropriate response e.g alter
- membrane permeability
- sensory activity
- metabolism
- rate of proliferation or differentiation
- contractile activity
When can a chemical messenger enter cells?
When it is lipid soluble
- hydrophobic molecules
- steroid hormones
Describe steroid hormones.
- Lipid soluble
- bind to intracellular receptors
- Often a transcription factor in the nucleus
- Alters rate of transcription
Describe NO.
- Lipid soluble
- Binds to soluble guanylyl cyclase
- Generates cGMP as second messenger which regulates cell activity.
What will you need for messengers that cannot enter the cell?
Cell surface receptors
What are the 4 tribes of cell surface receptors?
- Ionotropic receptors where the receptor is also and ion channel
- Receptors that function as enzymes
- Receptors that directly alter enzyme activity
- G protein couples receptors
What are the two types of enzymes you can get in an enzyme receptor?
- Tyrosine kinases which are involved in proliferation and differentiation
- Guanylyl cyclases in retina
What are receptors that interact with JAK kinases responsible for?
Protein synthesis
What are examples of ionotropic receptors?
- EPSPs
- IPSPSs
How many times do the G protein coupled receptors cross the plasma membrane?
7
What is the second messenger produced?
Adenylyl cyclase
What does adenylyl cyclase do?
Produced cAMP
What does cAMP do?
Regulates the activity of the enzyme PKA
What does PKA do once active?
Phosphorylates intracellular proteins as part of a signal cascade
What can the transmitter and 2nd messenger end up reregulating?
- Active transport
- Channels
- Protein synthesis
- Glycogen breakdown
- Lipid breakdown
- Secretion
- Transport of calcium ions
What are the secondary messengers produced by Phopslipase C?
- IP3
- DAG
What do DAG and IP3 do?
- Activate PKC
- Release Ca ions from internal state
What do G-proteins coupled directly to ion channels do?
Evoke slow EPSPs and slow IPSPs
What are 3 sources of calcium ions?
- From internal stores via IP3 or stimulated release Ca From ER
- From outside the cell wall via voltage gated or ligand gated Ca channels
- Via inhibition of Ca transport out of the cell
What are the effects of Ca?
-Directly affects target protein
Binds to calmodulin which then activates target protein CamKinase
-Works via some other Ca binding protein
