Pharmacodynamics: Main Targets of Drugs Quiz

Nicotinic and Muscarinic Receptors

• Nicotinic receptors are a type of ligand-gated ion channel that mediate fast synaptic transmission, functioning within milliseconds.
• Muscarinic acetylcholine receptors are classified as G-protein coupled receptors (GPCRs), playing a crucial role in the parasympathetic nervous system.

G-Protein Structure and Function

• G-proteins are composed of three subunits: α, β, and γ, with GDP bound to the α subunit in its inactive state.
• The activation of GPCRs leads to the dissociation of the G-protein subunits, which can then interact with various effector systems.

Types of G-Protein Coupled Receptors

• Dopamine receptors belong to the class of G-protein coupled receptors, influencing various physiological processes including mood and reward mechanisms.
• G-proteins facilitate communication between receptors and effector systems, which can include ion channels and enzymes.

Effector Systems

• G-protein effector systems include ion channels, which mediate cellular responses to neurotransmitter binding.
• The adenylate cyclase/cAMP system is another key effector pathway activated by G-proteins, regulating many biological processes.

Ion Channels and Transmission Types

• Ligand-gated ion channels play a significant role in fast synaptic transmission, allowing rapid changes in membrane potential.
• In contrast, GPCR-linked pathways typically mediate slower synaptic transmission, regulating longer-lasting physiological effects.