Fundamental Principles Of Cellular Signalling Flashcards
Where are electrical synapses found?
Endothelial cells
Cardiac myocytes
Epithelia
Which of the chemical synapses give the slow and which gives the fast response
Slow= G protein coupled receptors Fast= ligand gated ion channel receptors
What are the 4 types of cellular control receptors?
Ligand gated
G protein coupled
Tyrosine kinase linked
Nuclear
What are the 2 types of ion channels?
Voltage gated
Ligand gated
What are the 3 types of transporters?
Exchange
Symporters
AntiPorter s
What is an ion channel?
Proteinaceous pores that are basically holes through the membrane
Give the key features of ion channels (4)
- Aqueous pore connecting internal and external media
- gating mechanism that opens the pore
- High transfer rate (movement of many ions leads to a recordable current)
- selective permeability ( preference of one type of an ion over another
What’s a permeant ion?
The nature of ion that passes through the channel protein
What is a gating mechanism?
The nature of molecular mechanisms that open the ion pathway
Give examples of voltage gated channels (4)
Na+ channel
Ca2+ channel
K+ channel
Cl- channel
Give (3) examples of ligand gated channels
Neurotransmitter receptor
Ca2+ activated k+ channel
Cyclic nucleotide gated channel
What is an agonist?
Drug that binds to a receptor and elicits a biological response
What is an antagonist?
Drug that blocks the action of an agonist compound, commonly by binding to a receptor without eliciting a biological response
What is a partial agonist?
An agonist drug that produces a biological effect, but never the maximal of which the tissue is capable- partial agonists possess antagonistic properties
What is an inverse agonist?
An agonist that produces an opposing biological response to that observed by a full agonist
What is affinity?
The ability of a drug molecules to bind to a receptor site
What is efficacy?
Ability of a drug to elicit a biological response from a drug receptor intermediate
Give another name for a ligand gated ion channel
Ionotropic receptor
Give the (BASIC) steps in a ligand gated ion channel
Agonist binds to a cell surface receptor
Channel opens
Positive or negative charges come in and cause hyperpolarisation or depolarisation
Causes a pharmacological effect
What time frame does a ligand gated ion channel work in?
Super quick (milliseconds)
Give an example of a ligand gated ion channel
Nicotinic AchR
Give another name for a g-protein coupled receptor
Metabotropic
What is activation?
The pharmalogical effect of a drug
What are the types of bonding that are used in agonist bonding?
Hydrogen
Ionic
Van der waals
Covalent bonding
What does k1 stand for (receptors)?
Association rate
What does k-1 stand for (receptors)?
Dissociation rate
What’s the law of mass action as related to agonists and receptor
[Agonist]+[receptor] [ agonist receptor complex]
What is the law of mass action definition
The reversibility of binding is dependant on concentration of the reactants involved
What does an increase in agonist lead to?
Increase in agonist receptor complexes. There comes a point where are the receptors in the cells are filled (saturation point)
What is kd a measure of affinity
Conc of the drug where 50% of max number of receptors are bound by the drug
What does a lower kd mean for affinity?
Higher affinity
What is bmax?
Max number of receptors bound by drug
Define potency
Concentration of drug needed for effect. Lower conc = higher potency
What is the potency and efficacy of fentanyl?
High potency and efficacy
What is the potency and efficacy of morphine?
Kinda potent but highly efficacious
What is the potency and efficacy of aspirin?
Not very potent or efficacious
What is a drug for treatment of opioid addiction?
Burenorphine
What does burprenorphine do?
Reduces withdrawal effects
Reduces addictive highs
What molecules are competitive and non-competitive antagonism similar to
Enzymes
What happens if you overdose on opioids?
Respiratory depression
What is naloxone?
Competitive antagonist to oppose and has a stronger affinity to the receptors so good for treating opioid overdose
