Question | Answer |
Most receptors are located in... | the cell membrane |
Receptors are activated by... | Chemical messengers |
Chemical messengers include _____ and ______ | neurotransmitters and hormones |
Binding of messenger to receptor results in _______ _______ | Signal transduction |
Drug that mimics natural messenger is an _____ | agonist |
Agonist should bind and leave quickly or slowly? | quickly |
Drug that blocks natural messenger is an _____ | antagonist |
Antagonists alter induced fit due to _____ and/or _____ binding groups | stronger and/or more binding groups |
Agonist must have correct ____ , ______ and ____ _____ in order to work | correct shape , positioning and binding groups |
Enantiomers usually have ______ biological properties | different |
Agonists usually have _____ of interactions as natural messenger | same # |
Groups that block access to binding site are called ______ or ______ | steric blocks or steric shields |
Agents which bind to allosteric binding site rather than the messenger binding site | allosteric modulators |
Allosteric modulators _______ receptor activity | enhance |
Ex. of Allosteric modulator | benzodiazepines |
Benzodiazepines target allosteric site of | GABAa receptor |
Reversible antagonist binds _____ to receptor and produces different ____ ___ | reversibly , induced fit |
Does antagonist undergo rxn with receptor? | no rxn |
Level of antagonism depends on _____ of binding and _______ | strength and [antagonist] |
For reversible antagonist: increasing [messenger].... | lowers antagonism |
Irreversible antagonists bind _____ to receptor by form ______ bonds | irreversibly , covalent |
For irreversible antagonists: increasing [messenger]... | does not reverse antagonism |
Allosteric antagonist bind ______ to _______ site of receptor | reversibly , allosteric |
Alloseric antagonist work by.... | altering shape of receptor to block messenger action |
For Allosteric antagonists: increasing [messenger]... | does not reverse antagonism |
How does Antagonism by Umbrella effect work? | Antagonist binds to neighboring binding site and overlaps/covers messenger binding site |
______ ______ binds but does not produce maximum effect | Partial agonist |
Partial agonists act as _____ to one receptor subtype and ______ to different subtype | agonist , antagonist |
Define Inherent activity | any activity present in the absence of a chemical messenger |
Inverse agonist blocks ______ ______ of receptor | inherent activity |
Inverse agonist create equilibrium between ______ activity and _______ | inherent activity and inactivity |
Adding agonist pushed receptor toward _____ form | active |
Adding antagonist pushes receptor toward ____ form | inactive |
Adding partial agonist pushes receptor toward ______ between forms | equilibrium |
Receptors become ____ after long-term exposure to agonist | desensitized |
Prolonged binding of agonist leads to ______ of receptor | phosphorylation |
Phosphorylation _______ receptor until agonist leaves | deactivates |
Receptors become ______ after long-term exposure to antagonist | sensitized |
To compensate for antagonist-blocked receptors, cell.... | synthesizes new receptors |
Synthesis of new receptors makes cell more sensitive to _______ | natural messenger |
Long-term exposure to agonist can lead to ______ and ______ | tolerance and dependence |
Tolerance results in need to.... | increase dosage of antagonist |
Dependence results from ______ symptoms when antagonist is taken away | withdrawal |
Estradiol binding to estrogen receptor results in _______ and exposure of _____ | dimerization , AF-2 regions |
_______ binds to AF-2 regions of estrogen receptor in order to activate response | Coactivator |
Raloxifene is an estrogen receptor ______ and ______ agent | antagonist and anti-cancer |
Raloxifene works by preventing ______ so _____ regions are not exposed and coactivator doesn't bind | dimerization , AF-2 |
Tamoxifen is an estrogen receptor ______ | antagonist |