Podcast
Questions and Answers
Which of the following components is NOT part of a neuron?
Which of the following components is NOT part of a neuron?
What role do neurotransmitters play in the central nervous system?
What role do neurotransmitters play in the central nervous system?
Which neurotransmitter is primarily classified as an excitatory neurotransmitter?
Which neurotransmitter is primarily classified as an excitatory neurotransmitter?
In which part of the synapse are neurotransmitters released?
In which part of the synapse are neurotransmitters released?
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Which neurotransmitter is classified as inhibitory?
Which neurotransmitter is classified as inhibitory?
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What is the primary function of the synaptic cleft?
What is the primary function of the synaptic cleft?
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How are neurotransmitters synthesized in neurons?
How are neurotransmitters synthesized in neurons?
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Which ion is crucial for the release of neurotransmitters from vesicles?
Which ion is crucial for the release of neurotransmitters from vesicles?
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What is the primary role of the blood-brain barrier (BBB) in the central nervous system?
What is the primary role of the blood-brain barrier (BBB) in the central nervous system?
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Which neurotransmitter is primarily associated with excitatory functions in the central nervous system?
Which neurotransmitter is primarily associated with excitatory functions in the central nervous system?
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How are ionotropic receptors characterized?
How are ionotropic receptors characterized?
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Which structure connects the peripheral nervous system (PNS) to the central nervous system (CNS)?
Which structure connects the peripheral nervous system (PNS) to the central nervous system (CNS)?
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Which of the following describes presynaptic receptors?
Which of the following describes presynaptic receptors?
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What influences the properties of heterogeneous ionotropic receptors?
What influences the properties of heterogeneous ionotropic receptors?
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Which neurotransmitter is known for modulating mood and emotional responses?
Which neurotransmitter is known for modulating mood and emotional responses?
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Which statement about GABAA and GABAB receptors is accurate?
Which statement about GABAA and GABAB receptors is accurate?
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What is a characteristic of metabotropic receptors?
What is a characteristic of metabotropic receptors?
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How do presynaptic autoreceptors function?
How do presynaptic autoreceptors function?
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What outcome is associated with sustained activation of postsynaptic receptors?
What outcome is associated with sustained activation of postsynaptic receptors?
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Which neurotransmitter is characterized as generally inhibitory?
Which neurotransmitter is characterized as generally inhibitory?
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What type of receptor is primarily affected by drugs that lead to tolerance?
What type of receptor is primarily affected by drugs that lead to tolerance?
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Which term describes a reduction in the number of receptors due to long-term neurotransmitter activation?
Which term describes a reduction in the number of receptors due to long-term neurotransmitter activation?
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What is the role of heteroreceptors at presynaptic sites?
What is the role of heteroreceptors at presynaptic sites?
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Study Notes
CNS Pharmacology Objectives
- Discuss the significance of the blood-brain barrier (BBB).
- Study synapses and synaptic potentials.
- Study synapses and drug action sites (hierarchical and nonspecific/diffuse neuronal systems excluded from final exam).
- Identify major CNS neurotransmitter receptor subtypes and receptor regulation.
Presynaptic Receptors (Chapter 6)
- Postsynaptic receptors.
- Ionotropic ligand-gated ion channels: composed of subunits; 4 membrane-spanning domains; various combinations form slightly different receptors.
- Metabotropic receptors (linked to G-proteins): have seven transmembrane domains.
- Study major excitatory CNS neurotransmitters (glutamate and aspartate).
Additional CNS Neurotransmitters
- Study the following neurotransmitters: types, receptor subtypes, mechanisms, preferred agonists, and antagonists: acetylcholine, dopamine, GABA, glutamate, glycine, serotonin, norepinephrine, and orexins.
- Discuss CNS adaptation to prolonged drug exposure.
The Human Nervous System
- The nervous system separates into peripheral and central components.
- Peripheral further divides into afferent (sensory) and efferent (motor).
- Efferent further divides into somatic (skeletal muscle) and autonomic (internal organs and glands).
- Autonomic further divides into sympathetic (energy expenditure) and parasympathetic (energy conservation).
- Central further divides into brain and spinal cord.
Physiology of the CNS
- The CNS begins at the spinal cord, connecting with the afferent and efferent peripheral nervous system neurons.
- This connection allows for higher-level brain processing and executive control.
- The brain controls motor and cognitive functions, as well as emotional and intellectual functions.
Blood-Brain Barrier (BBB)
- The BBB, or blood-brain barrier, is a critical part of the CNS.
- It is a tight junction that regulates molecule permeability between the blood capillary system and the CNS.
- Lipid-soluble molecules easily cross, but ionized or polar molecules do not.
Organization of the CNS
- Neurons: form the basis of the CNS.
- Neuroglia: support neurons.
- Blood-brain barrier: critical to CNS function/integrity.
Neurons
- Nerve cells composed of cell bodies, axons, and dendrites.
- Synapses: the basis of neurochemical communication.
Types of Ion Channels and Neurotransmitter Receptors in the CNS
- Diagrams demonstrating voltage-gated, ligand-gated, and metabotropic receptors.
- Mechanisms of membrane-delimited & diffusible second messenger-mediated regulation of ion channels.
The Synapse
- Axon terminal of the presynaptic neuron.
- Dendrite of the postsynaptic neuron.
- Synaptic cleft: gap between the two structures listed above.
Neurotransmitter Release and Action
- Diagram depicting neurotransmitter synthesis, storage, release, receptor interaction, uptake, and degradation.
Neurotransmitters in the CNS (Part 1)
- Neurotransmitters act as messengers enabling neuron-to-neuron communication.
- They are present in high concentrations at the synaptic area.
- Release triggered by electrical or chemical stimulation (calcium-dependent).
- Neurotransmitters must exhibit synaptic mimicry (mimic the effects of actual nerve signals).
Neurotransmitters in the CNS (Part 2)
- Neurotransmitters are synthesized in presynaptic neurons (cell bodies/terminals).
- They are stored in vesicles.
- Stimulation increases [Ca2+]i, leading to vesicle fusion with the presynaptic membrane.
- Neurotransmitters in the synaptic cleft are released, then diffuse to postsynaptic receptors.
Postsynaptic Potential
- Graph illustrating action potential propagation, EPSPs (excitatory postsynaptic potentials), and IPSPs (inhibitory postsynaptic potentials).
- Spatial and temporal summation of potentials are also explained in the figure.
Examples of Major Neurotransmitters in the CNS
- Amino acids: glutamate, GABA, and glycine.
- Acetylcholine.
- Monoamines: dopamine, norepinephrine, serotonin, and histamine.
- Neuropeptides: orexin.
Excitatory Neurotransmitters
- Glutamate: major excitatory neurotransmitter (amino acid).
- Acts on NMDA (Ca2+, ionotropic), AMPA (ionotropic excitatory cation conductance), and metabotropic receptors (mGluR).
Inhibitory Neurotransmitters
- GABA (γ-aminobutyric acid): major inhibitory neurotransmitter (amino acid).
- Acts on GABAA (receptor-operated Cl- channel, ionotropic) and GABAB receptors (coupled to G proteins, metabotropic).
- Barbiturates, benzodiazepines, and some anticonvulsants influence GABAergic systems.
Amines Neurotransmitters
- Dopamine (generally inhibitory).
- Norepinephrine.
- Serotonin (5HT).
- Substance P.
Neurotransmitter Receptors
- Metabotropic receptors: membrane receptors acting through secondary messengers.
- Ionotropic receptors: Form ion channels.
Receptor Regulation
- Receptor sensitization (up-regulation): increased receptor numbers due to sustained reduction in neurotransmitter release or long-term antagonist use.
- Receptor desensitization (down-regulation): decreased receptor numbers due to sustained increase in neurotransmitter release, reuptake blockade, or long-term drug activation.
- Receptor regulation is one primary cause of drug tolerance.
Sites of Drug Action
- Refer to textbook figure 21-4 for locations of drug action.
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Description
Test your knowledge on CNS pharmacology with a focus on presynaptic and postsynaptic receptors discussed in Chapter 6. This quiz covers neurotransmitter types, receptor subtypes, and their regulatory mechanisms. Prepare to explore the intricacies of CNS drug action and neurotransmitter interactions.
