Terms to learn Flashcards
What is a receptor
A protein molecule embedded within the cell membrane, or free in the cell interior. They have an affinity for specific chemical groups, molecules or viruses. When such things bing to the receptor, they cause some form of cellular or tissue response.
What is a binding domain on a receptor?
Complex shapes on the surface of the protein receptors with hollows and ridges, and this domain has a specific shape to accept incoming messengers.
What is a chemical messenger?
It is a molecule that will fit to the binding domain of a receptor if the shape is right, and ‘switches on’ the receptor molecule to receive a message. The chemical messenger then leaves unchanged.
What is an Agonist drug?
These are drugs that mimic the NATURAL TRANSMITTER and are useful in treating a shortage in the natural compound. They will initiate a physiological response when bound to the binding site of receptors.
What must the active site of the agonist do for binding?
The active site on the agonist must complement the binding domain on the receptors for binding to occur.
What are the 5 different types of agonists?
Full agonist Co-agonist Partial agonist Inverse agonist Irreversible agonist
What is a Full agonist?
It will bind and activate a receptor with the maximum response that an agonist can elict at the receptor.
What is a co-agonist?
It works in conjugation with other agonists to produced the desired effect, similar to what the natural transmitter would elict, by binding receptors.
What is a partial agonist?
It will bind and activate a given receptor, but will only have partial efficacy at the receptor compared to the full agonist. Even at maximal binding, the response is not maximum.
What is an Inverse agonist?
This is similar to an antagonist. It will compete and bind to receptors that an agonist would normally bind to, but it will also cause the opposite response and pharmocological effect to what an agonist would do. (an antagoist dosen’t cause the opposite response, it only competes with the agonist to block the agonist response.)
What is an Irreversible Agonist?
It will bind permanently to the receptor by forming covalent bonds.
What is an Antagonist?
A type of receptor ligand or drug that competes and binds to the recptors, blocking the agonist from binding. This dampens the biological response because an antagonist doesn’t switch on the receptor like an agonist would.
What are the different types of antagonists? HINT: 2 main types, and 2 sub-groups of 1 main type
Competitive Antagonist: Reversible or Irreversible
Non-competitive antagonist
What is a competitive antagonist and the sub-groups?
It will bind to receptors at the same binding site as the agonist. Sufficient concentration of a competitive antagonist will displace an already bound agonist, resulting in a lower frequency of receptor activation. The two sub-groups are Reversible or Irreversible, depending on the interaction.
What is a non-competitive antagonist?
Unlike competitive antagonists, these will reduce the magnitude of the maximum response that can be attained by any amount of agonist. The non-competitive antagonist will bind to an ALLOSTERIC site of the receptor (away from binding domain), displacing and agonist already bound, and preventing any more binding.
