Neuroscience Chapter: Glial Cells & Synaptic Transmission

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Questions and Answers

Which neurotransmitter is primarily associated with the locus coeruleus?

Acetylcholine

Noradrenaline (correct)

Dopamine

Serotonin

Glutamate is primarily an inhibitory neurotransmitter.

False

What type of receptors are α1 and β1,2 receptors classified as?

excitatory receptors

Noradrenaline is associated with the ______ brain region.

locus coeruleus Signup and view all the answers

Match the following brain regions with their associated neurotransmitter:

Locus coeruleus = Noradrenaline Raphe = Serotonin TMN = Histamine Substantia nigra = Dopamine Signup and view all the answers

Which metabotropic glutamate receptor group is located post-synaptically?

Group I Signup and view all the answers

What type of receptor activates a second messenger system inside neurons?

Metabotropic receptors Signup and view all the answers

Lipid and peptide transmitters are released via electrical signaling.

False Signup and view all the answers

What is the primary function of GABA in the central nervous system?

inhibition Signup and view all the answers

Ionotropic receptors cause ion channels to open directly upon activation.

True Signup and view all the answers

Name one ion channel that is voltage dependent.

NaV Signup and view all the answers

The process of developing new pharmaceutical drugs is known as ______.

drug discovery Signup and view all the answers

TRPV1 is activated by ______ and capsaicin.

heat Signup and view all the answers

Which type of receptor can act as both an autoreceptor and a heteroreceptor?

Autoreceptors Signup and view all the answers

Match the ion channel category with its associated feature:

NaV = Activated by low (negative) voltage Cav = Has high and low voltage channels Kv = Mainly high voltage (positive) channels TRP = Sensory ion channels activated by environmental stimuli Signup and view all the answers

Which of the following is a function of autoreceptors?

Inhibit neurotransmitter release Signup and view all the answers

Heteroreceptors are the same as autoreceptors.

False Signup and view all the answers

What is the difference between EPSPs and IPSPs?

EPSPs depolarize the membrane, while IPSPs hyperpolarize the membrane. Signup and view all the answers

_______ channels are primarily responsible for generating action potentials.

Voltage-gated sodium (NaV) Signup and view all the answers

Which of the following ions typically flow through CaV channels?

Calcium (Ca2+) Signup and view all the answers

Study Notes

Glial Cells

Astrocytes: support neurons, maintain chemical environment, blood brain barrier
Oligodendrocytes: produce myelin in the CNS
Schwann cells: produce myelin in the PNS
Microglia: immune cells of the CNS

Synaptic Transmission

Presynaptic membrane: release neurotransmitters
Postsynaptic membrane: receptors bind neurotransmitters
Autoreceptors: receptors on the presynaptic terminal that bind the neurotransmitter released by the same neuron
Heteroreceptors: receptors on the presynaptic terminal that bind a neurotransmitter released by a different neuron

Ionotropic vs. Metabotropic Receptors

Ionotropic receptors: directly open ion channels after ligand binding, fast response
Metabotropic receptors: activate a second messenger system inside the neuron, leading to channel opening, slower response

Neurotransmission Termination

Reuptake: neurotransmitters are reabsorbed by the presynaptic terminal using transporter proteins
Enzymatic degradation: neurotransmitters are broken down by enzymes
Diffusion: neurotransmitters diffuse away from the synapse

Excitatory Postsynaptic Potential (EPSP) and Inhibitory Postsynaptic Potential (IPSP)

EPSP: depolarizing potential, increases likelihood of action potential
IPSP: hyperpolarizing potential, decreases likelihood of action potential
Voltage-dependent ion channels: open based on membrane potential
Ligand-gated ion channels: open when a ligand binds to the receptor

Ion Channels

Voltage-dependent channels:
- Sodium channels (NaV): activated by low (negative) voltage, responsible for the rising phase of the action potential
- Calcium channels (CaV): activated by high and low voltage, roles in neurotransmitter release and neuronal plasticity
- Potassium channels (Kv): activated by high (positive) voltage, repolarize the membrane after an action potential
Ionotropic/Ligand-gated channels:
- P2X: activated by ATP, permeable to cations
- TRP: activated by various stimuli including heat, cold, and environmental toxins
- nAChR: activated by acetylcholine, permeable to cations

Glutamate Receptors

NMDA: activated by glutamate and glycine, permeable to sodium, potassium, and calcium, involved in learning and memory
AMPA: activated by glutamate, permeable to sodium and potassium, fast-acting
Kainate: activated by glutamate, contributes to synaptic plasticity

TRP Channels

TRPV1: activated by heat and capsaicin (spicy chili pepper)
TRPA1: activated by mustard oil, wasabi, and environmental toxins
TRPM8: activated by menthol and cool/cold temperatures

Neurotransmitters

Acetylcholine (Ach):
- Origin: basal forebrain, hippocampus, brainstem
- Receptor: nicotinic (nAchR) and muscarinic (mAChR)
- Inhibition: muscarinic autoreceptors
Dopamine (DA):
- Origin: substantia nigra, ventral tegmental area
- Receptor: D1-D5
- Inhibition: D2 autoreceptors
Noradrenaline (NA or NE):
- Origin: locus coeruleus, brainstem
- Receptor: alpha (α1, α2) and beta (β1, β2)
- Inhibition: alpha2 (α2) autoreceptors
Histamine:
- Origin: tuberoinfundibular nucleus (TMN)
- Receptor: H1-H4
- Inhibition: H3 autoreceptors
Serotonin (5-HT):
- Origin: raphe nuclei, brainstem
- Receptor: 5-HT1-5-HT7
- Inhibition: 5-HT1 autoreceptors
Glutamate:
- Function: excitatory
- Location: throughout the CNS
GABA:
- Function: inhibitory
- Location: throughout the CNS
Metabotropic glutamate receptors:
- Group I (mGluR1, mGluR5): postsynaptic, excitatory
- Group II (mGluR2, mGluR3): presynaptic, inhibitory autoreceptors
- Group III (mGluR4, mGluR6, mGluR7, mGluR8): presynaptic, inhibitory heteroreceptors

Lipid and Peptide Transmitters

Lipid transmitters: released from phospholipid membranes, retrograde signaling
- Example: endocannabinoids (anandamide)
Peptide transmitters: synthesized as larger proteins and cleaved into smaller peptides before release
- Example: endorphins, substance P

Drug Discovery

Preclinical studies: animal testing
Phase I clinical trials: safety and dosage in healthy subjects
Phase II clinical trials: effectiveness and optimal dosage in target population
Phase III clinical trials: large-scale trials comparing drug to standard treatment
Phase IV clinical trials: post-marketing surveillance to monitor long-term effects and identify adverse reactions

Text Subsections

Chapter 2:
- LO 2.3: Cellular Structures
- LO 2.10: Neurotransmitters
- LO 2.11: Synthesis and Storage
- LO 2.12: Release
- LO 2.13: Synaptic Communication
- LO 2.14: Receptor Binding
- LO 2.15: Neurotransmission Termination
- LO 2.16: Receptor Signaling
Chapter 4:
- LO 4.10: Drug Discovery and Development
- LO 4.11: Drug Administration
- LO 4.12: Drug Metabolism
- LO 4.13: Drug Distribution
- LO 4.14: Drug Excretion

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Test your knowledge on glial cells and their functions, including astrocytes, oligodendrocytes, and microglia. Additionally, delve into synaptic transmission, receptor types, and neurotransmission termination mechanisms. This quiz covers key concepts necessary for understanding nervous system operations.