Pharmacology 1 Flashcards
Why don’t receptors all bind the same signalling molecules?
Allows the cells to specialise, so they don’t all perform the same function
Different receptors can be activated by
Different and sometimes even the same signalling molecule
What type of response can a receptor evoke?
Membrane permeability
Metabolism
Secretory activity
Rate of proliferation or differentiation
contractile activity
The process is called signal transduction
What type of chemical messenger binds to an intracellular receptor?
A lipid soluble receptor, steroid hormones
Where are the receptors found that can influence the transcription of DNA?
Within the nucleus
What response can steroids have on transcription?
They are a transcription factor and can alter the rate of transcription
Where is the receptor for the chemical messenger for the chemical messenger NO (nitric oxide)
Within the cell as NO is lipophilic
How many different types of cell surface receptors exist?
4
Describe the 4 different types of cell surface receptors
Ionotropic- receptor channel- The receptor is also an ion channel
Receptor that functions as an enzyme - Receptor enzyme
Integrin receptor - Receptor that directly affects cytoskeleton
G-Protein coupled receptors
What happens to a subunit of a G protein when the G protein coupled receptor is activated?
It regulates an enzyme that produces a secondary messenger, e.g
Regulates adenyl cyclase, which in turn produces the second messenger cAMP (cyclic AMP), This in turn regulates the activity of another enzyme, PKA (protein kinase A) which then goes off to phosphorylate proteins
Give the possible effects of a secondary messenger
Make channels open wider
Regulate protein synthesis
Regulate the release of calcium
Regulate the synthesis of RNA in the nucleus
Might act on microtubules making things secrete things out of the cell
What happens when phospholipase C is regulated?
Two secondary messengers are regulated, these (diacylglycerol and Inisitol triphosphate) - These are responsible for activation of Protein Kinase C and the release of calcium ions from internal stores
What effect can G proteins have on ion channels?
They can evoke a slow EPSP/ Slow IPSP
What are the sources of calcium ions?
Internal stores via inisitol triphosphate
From outside the cell via ligand or voltage gated channels
Via inhibition of calcium transport out the cell
What are the effects of calcium in the cell?
Can regulate the activity of the target protein e.g of Protein Kinase C
Can bind to calmodulin which directly activates a target protein
Works via some other calcium binding protein e.g troponin
