Pharmacodynamics Flashcards
What is pharmacodynamics?
The study of what a drug does to the body – its biological and physiological effects
What are the main receptor subtypes in relation to psychotropic drug actions?
- Dopaminergic (D1 - D5)
- Serotonergic (5-HT1 to 5-HT7)
- Noradrenergic (α1, α2, β)
- Cholinergic (muscarinic and nicotinic)
- GABAergic (GABA-A, GABA-B)
- Glutamatergic (NMDA, AMPA)
- Histaminergic (H1)
- Opioid receptors (μ, κ, δ)
What are the receptor types/ superfamilies?
- Metabotropic receptors (G protein-coupled receptors - GPCRs)
- Ionotropic receptors
What are metabotropic receptors?
Receptors are linked to G proteins which when activated imitates a reaction within the cell
…
(slower-acting)
What are ionotropic receptors?
Receptors that when activated, mediates its effect by opening an ion channel on the surface of a cell
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(fast-acting)
Give examples of metabotropic receptors
- Dopaminergic (D1 - D5)
- Serotonergic (all apart from 5HT-3)
- Noradrenergic (α1, α2, β)
- Cholinergic (muscarinic)
- GABAergic: GABA-B only
- Histaminergic (H1)
- Opioid receptors (μ, κ, δ)
Give examples of ionotropic receptors
- Serotonergic: 5HT-3 only
- Cholinergic (nicotinic)
- GABAergic: GABA-A only
- Glutamatergic: NMDA, AMPA
What is meant by the term affininity?
The strength of binding between drug and receptor
What is the Dissociation constant (Kd)?
What is meant by the term “intrinsic activity”?
A drug’s ability to activate a receptor upon binding
What is an agonist?
A drug that binds and activates a receptor fully
…
(e.g. morphine)
What is a partial agonist?
A drug that binds to a receptor but with less intrinsic activity
…
(e.g. aripiprazole at D2)
What is an antagonist?
A drug that binds to a receptor however does not activate it but rather blocks agonists
…
(e.g. haloperidol)
What is an inverse agonist?
A drug that binds to a receptor and produces opposite effect to an agonist
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(e.g. some antihistamines)
Activating a receptor triggers what signalling cascades?
- Second messengers: cAMP, IP3, DAG.
- . Enzyme activation: Protein kinase A/C.
- Gene expression: Transcription factors like CREB regulate protein synthesis.
