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Questions and Answers
Which characteristic distinguishes neurotransmission from neuromodulation in cell signaling?
Which characteristic distinguishes neurotransmission from neuromodulation in cell signaling?
- Neurotransmission primarily operates over longer distances, whereas neuromodulation is confined to local tissue.
- Neurotransmission is characterized by rapid signal transmission, while neuromodulation is associated with slower, longer-lasting effects. (correct)
- Neurotransmission involves direct neurochemical signaling, whereas neuromodulation primarily utilizes hormonal signaling.
- Neurotransmission is typically slower due to reliance on second messenger systems, unlike the faster neuromodulation.
What is the primary mechanism by which ionotropic receptors influence the membrane potential ($V_m$) of a neuron?
What is the primary mechanism by which ionotropic receptors influence the membrane potential ($V_m$) of a neuron?
- Activation of intracellular second messenger cascades that indirectly alter ion channel conductance.
- Releasing intracellular calcium stores that then trigger changes in membrane permeability to ions.
- Initiating G protein signaling pathways that subsequently modify the activity of nearby ion channels.
- Directly altering $V_m$ through the flux of ions across the membrane via an integral ion channel. (correct)
Metabotropic receptors are characterized by their association with which type of protein?
Metabotropic receptors are characterized by their association with which type of protein?
- Receptor tyrosine kinase proteins that activate phosphorylation pathways.
- GTP-binding proteins that initiate intracellular signaling cascades. (correct)
- Voltage-gated ion channel proteins that respond to changes in membrane potential.
- Ligand-gated ion channel proteins that directly mediate ion flux.
Which of the following is an example of a metabotropic acetylcholine receptor (mAchR)?
Which of the following is an example of a metabotropic acetylcholine receptor (mAchR)?
Considering the speed of signal transmission, how do ionotropic and metabotropic receptors compare in mediating chemical neurotransmission?
Considering the speed of signal transmission, how do ionotropic and metabotropic receptors compare in mediating chemical neurotransmission?
What structural feature is characteristic of metabotropic receptors but not ionotropic receptors?
What structural feature is characteristic of metabotropic receptors but not ionotropic receptors?
Following the activation of a metabotropic receptor, what is the primary function of the G protein α subunit?
Following the activation of a metabotropic receptor, what is the primary function of the G protein α subunit?
In the cyclic AMP signaling system, which enzyme is activated directly by the G protein to produce the second messenger?
In the cyclic AMP signaling system, which enzyme is activated directly by the G protein to produce the second messenger?
Within the Phosphatidyl Inositol signaling system, phospholipase C catalyzes the production of which pair of second messengers?
Within the Phosphatidyl Inositol signaling system, phospholipase C catalyzes the production of which pair of second messengers?
Phosphorylation of which cellular component is a convergent downstream effect observed in both the cyclic AMP and Phosphatidyl Inositol signaling pathways?
Phosphorylation of which cellular component is a convergent downstream effect observed in both the cyclic AMP and Phosphatidyl Inositol signaling pathways?
Which type of acetylcholine receptor is predominantly involved in mediating the inhibitory effects of acetylcholine on cardiac muscle?
Which type of acetylcholine receptor is predominantly involved in mediating the inhibitory effects of acetylcholine on cardiac muscle?
What is the primary mechanism by which muscarinic acetylcholine receptors (mAchR) influence cardiac muscle function?
What is the primary mechanism by which muscarinic acetylcholine receptors (mAchR) influence cardiac muscle function?
Curare and bungarotoxin are identified as antagonists for which type of acetylcholine receptor?
Curare and bungarotoxin are identified as antagonists for which type of acetylcholine receptor?
Which of the following best describes the 'M-type K channel' in the context of acetylcholine receptor pharmacology?
Which of the following best describes the 'M-type K channel' in the context of acetylcholine receptor pharmacology?
What distinguishes ionotropic receptors, like the nicotinic acetylcholine receptor (nAchR), from metabotropic receptors, like the muscarinic acetylcholine receptor (mAchR)?
What distinguishes ionotropic receptors, like the nicotinic acetylcholine receptor (nAchR), from metabotropic receptors, like the muscarinic acetylcholine receptor (mAchR)?
Otto Loewi's experiment, which identified 'vagustuffe', is most directly related to the discovery of:
Otto Loewi's experiment, which identified 'vagustuffe', is most directly related to the discovery of:
In the sympathetic ganglion, the 'slow EPSP' resulting from muscarinic acetylcholine receptor activation is characterized by:
In the sympathetic ganglion, the 'slow EPSP' resulting from muscarinic acetylcholine receptor activation is characterized by:
Considering the pharmacology of acetylcholine receptors, which of the following pairs correctly matches the receptor type with its primary effect in the specified tissue?
Considering the pharmacology of acetylcholine receptors, which of the following pairs correctly matches the receptor type with its primary effect in the specified tissue?
Which form of synaptic plasticity is characterized by changes in synaptic efficacy resulting from the neuron's own activity?
Which form of synaptic plasticity is characterized by changes in synaptic efficacy resulting from the neuron's own activity?
The 'residual calcium hypothesis' primarily explains the mechanism of which type of synaptic plasticity?
The 'residual calcium hypothesis' primarily explains the mechanism of which type of synaptic plasticity?
Long-term potentiation (LTP), a key mechanism in learning and memory, is primarily associated with synaptic changes in which brain regions?
Long-term potentiation (LTP), a key mechanism in learning and memory, is primarily associated with synaptic changes in which brain regions?
Activation of NMDA glutamate receptors in the postsynaptic neuron directly leads to an influx of which ion that initiates downstream signaling cascades in LTP?
Activation of NMDA glutamate receptors in the postsynaptic neuron directly leads to an influx of which ion that initiates downstream signaling cascades in LTP?
In pre-synaptic facilitation, an interneuron enhances neurotransmitter release from another neuron by primarily acting on which aspect of the pre-synaptic action potential?
In pre-synaptic facilitation, an interneuron enhances neurotransmitter release from another neuron by primarily acting on which aspect of the pre-synaptic action potential?
Enkephalin's role in spinal cord modulation of pain exemplifies which type of synaptic plasticity?
Enkephalin's role in spinal cord modulation of pain exemplifies which type of synaptic plasticity?
Hetero-synaptic inhibition, leading to a reduction in neurotransmitter release, is often mediated by changes in pre-synaptic ion channel conductance that result in:
Hetero-synaptic inhibition, leading to a reduction in neurotransmitter release, is often mediated by changes in pre-synaptic ion channel conductance that result in:
What is the fundamental distinction between homo-synaptic and hetero-synaptic plasticity in terms of the source of the synaptic change?
What is the fundamental distinction between homo-synaptic and hetero-synaptic plasticity in terms of the source of the synaptic change?
Flashcards
Homo-synaptic plasticity
Homo-synaptic plasticity
A change in the strength of a synapse due to activity at the same synapse.
Homo-synaptic facilitation
Homo-synaptic facilitation
Short-term increase in neurotransmitter release at a synapse due to repeated stimulation.
Homo-synaptic potentiation (post-tetanic potentiation)
Homo-synaptic potentiation (post-tetanic potentiation)
Long-term increase in neurotransmitter release at a synapse due to a strong burst of activity.
Homo-synaptic depression
Homo-synaptic depression
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Residual calcium hypothesis
Residual calcium hypothesis
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Hetero-synaptic plasticity
Hetero-synaptic plasticity
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Pre-synaptic facilitation
Pre-synaptic facilitation
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Pre-synaptic inhibition
Pre-synaptic inhibition
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Ionotropic receptors
Ionotropic receptors
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Metabotropic receptors
Metabotropic receptors
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G protein activation
G protein activation
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Cyclic AMP signaling
Cyclic AMP signaling
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Phosphatidylinositol signaling
Phosphatidylinositol signaling
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G Protein-Coupled Receptor (GPCR)
G Protein-Coupled Receptor (GPCR)
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Synaptic Plasticity
Synaptic Plasticity
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Paracrine Signaling
Paracrine Signaling
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mAchR and cardiac muscle
mAchR and cardiac muscle
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mAchR and heart rate
mAchR and heart rate
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Nicotinic acetylcholine receptor (nAchR)
Nicotinic acetylcholine receptor (nAchR)
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nAchR and ion flux
nAchR and ion flux
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Muscarine
Muscarine
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Atropine
Atropine
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Curare
Curare
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Study Notes
Cell Signaling and Neurotransmission
- Neurotransmission is categorized as ionotropic or metabotropic.
- Ionotropic receptors are ligand-gated ion channels, enabling fast chemical transmission.
- Metabotropic receptors utilize G proteins, leading to slower chemical transmission and modulation.
- Acetylcholine (ACh) receptors exist in both ionotropic (nicotinic) and metabotropic (muscarinic) forms.
- Nicotinic ACh receptors are directly gated, found in neuromuscular junctions, and are responsible for fast excitatory responses.
- Muscarinic ACh receptors are indirectly gated, involve G proteins, and influence cardiac muscle responses.
- Ligand-gated receptors are quickly activated by a ligand binding to their respective receptors, resulting in rapid changes in membrane potential.
- G protein-coupled receptors (GPCRs) are also known as metabotropic receptors, interacting with G protein, initiating intracellular signaling cascades.
Second Messenger Systems
- Cyclic AMP (cAMP) and cyclic GMP (cGMP) are cyclic nucleotides.
- Phosphatidylinositol is a secondary messenger involved in signaling.
- Calcium ions (Ca2+) and calmodulin play vital roles in intracellular signaling.
- Protein kinases are enzymes activated by secondary messengers, affecting various cellular activities through phosphorylation.
Synaptic Plasticity
- Homo-synaptic plasticity and hetero-synaptic plasticity represent different forms of synaptic modulation.
- Homo-synaptic mechanisms such as facilitation, potentiation (post-tetanic), and depression explain changes in excitatory postsynaptic potentials (EPSPs).
- Hetero-synaptic mechanisms involving pre and post-synaptic interactions alter synaptic efficacy.
- Modulation in synaptic strength (increase or decrease) is controlled by calcium levels at presynaptic terminals.
- These processes are essential for learning and memory formation, involving changes in synaptic strength and efficiency over time.
Neurotransmission vs. Neuromodulation
- Ionotropic receptors, with 4 transmembrane (TM) subunits, cause immediate changes in membrane potential (altered VM).
- Metabotropic receptors, with 7 TM segments, initiate slower, amplified responses via secondary messengers.
- Neuromodulation affects the strength of neurotransmission, not generating action potentials itself.
Ach Receptor Pharmacology
- Nicotinic ACh receptors are directly gated ion channels affected by agonists (e.g., nicotine) and antagonists (e.g., curare, bungarotoxin).
- Muscarinic ACh receptors are indirectly gated and influenced by agonists (e.g., muscarine) and antagonists (e.g., atropine, scopolamine).
- ACh receptors are crucial in various tissues (e.g., skeletal muscle, heart CNS).
- ACh functions in both excitatory (skeletal muscle) and inhibitory (cardiac muscle) capacities.
Other Biochemical Systems
- Cyclic GMP (cGMP) is involved in photoreceptor function and nitric oxide signaling.
- Ca2+/calmodulin/CamKII is a system linked to learning and nitric oxide.
- Second messengers like diacyl glycerol (DAG) and inositol trisphosphate (IP3) are produced following activation of phospholipase C.
Enkephalin in Spinal Cord Modulation of Pain
- Enkephalin, a neuropeptide, modulates pain signaling in the spinal cord.
- By pre-synaptic mechanisms, enkephalin reduces the release of substance P and associated pain pathways.
Hetero-synaptic Plasticity
- Pre-synaptic facilitation refers to an increase in neurotransmitter release.
- Pre-synaptic inhibition refers to a decrease in neurotransmitter release.
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