Receptors Flashcards
Ligands
chemical substances that bind to a specific receptor
agonists
binds to a receptor and stimulates the function that receptor serves
antagonists
binds to a receptor and blocks the function that receptor serves
competitive binding
reversible binding with the receptor - it’ll wear off/terminate
noncompetitive
irreversible binding - in order for bond to be broken receptor or cell would have to be destroyed
ED50
effective dose in 50% of the population
TD50
toxic dose in 50% of the population
LD50
lethal dose in 50% of the population
LD50/ED50
Therapeutic index - the higher, the safer the drug is
TD50/ED50
therapeutic window - estimation of drug dosage which can treat disease effectively while staying within the safety range
receptor
macromolecular complex which acts as the site of action for a drug. They are usually proteins involved in a production of normal cellular function. They may include membrane proteins, enzymes, carrier molecules, ion channels, nucleic acids.
Bond strength of the chemical bonds
Covalent > Ionic > Hydrogen > Hydrophobic > van der Waals
“Can I have higher valuables?”
Down regulation
continued stimulation of cells with agonists generally results in a state of desensitization - cells decrease the number of receptors for a given drug in response to chronic stimulation (insulin/glucose relationship in DM)
Up regulation
process by which a cell increases the number of receptors to a given drug (chronic blockage with BBs)
Interaction
alteration in the therapeutic action of a drug by concurrent administration of other exogenous chemicals
Addition
the combined effect of two drugs acting via the same mechanism is equal to that expected by simple addition of their individual actions.
1 + 1 = 2
Synergism
the combined effect of two drugs is greater than the algebraic sum of their individual effects
1 + 1 = 3
Potentiation
the enhancement of the action of one drug by a second drug that has no detectable action of its own
1 + 0 = 3
Antagonism
the action of one drug opposes the action of another
1 + 1 = 0
Is preganglionic neuron longer in PNS or SNS?
PNS
drug that mimics the action of the PNS?
parasympathomimetic
drug that blocks action in the PNS?
parasympatholytic
What is a sympatholytic drug?
drug that blocks action of SNS
What is a sympathomimetic drug?
drug that mimics the action of the SNS
What NT is released from preganglionic neuron in PNS and what receptor is it?
ACh - nicotinic cholinergic receptor
What NT is released from preganglionic neuron in SNS and what receptor is it?
ACh - nicotinic cholinergic receptor
What NT is released from postganglionic neuron in PNS and what receptor is it?
ACh - muscarinic cholinergic receptor
What NT is released from postganglionic neuron in SNS and what receptor is it?
NE - adrenergic receptor
