methods in research in cellular neuroscience- lecture 4

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Questions and Answers

What is the primary function of the human M3 muscarinic DREADD?

Non-specific activation of various cell types

Excitation of neurons via the Gq pathway (correct)

Silencing neurons through Gi signaling

Inhibitory signaling through K+ channels

Which technique allows for cell-specific targeting based on protein distribution?

Chemogenetics

Extracellular recordings

Cell-specific promoters (correct)

Optogenetics

What is the role of cloazapine-N-oxide (CNO) in the function of DREADDs?

It inhibits synaptic transmission.

It serves as an activator for engineered receptors. (correct)

It causes neuronal death.

It activates native receptor functions.

What advantage does optical manipulation provide in neuronal studies?

Ability to target precise locations within the brain Signup and view all the answers

How does the human M4 muscarinic DREADD function at the cellular level?

By opening K+ channels to silence neurons Signup and view all the answers

What is a significant consideration when choosing a technique for neuronal experimentation?

The compatibility with experimental questions Signup and view all the answers

What is one of the primary characteristics of chemogenetics?

Non-invasive methods for manipulating neurons Signup and view all the answers

What advantage do optical studies provide in the context of brain activity investigations?

Enhancement of temporal resolution and specificity Signup and view all the answers

Which of the following would be the least effective in activating neurons using chemogenetics?

Human M4 muscarinic DREADD Signup and view all the answers

What is a critical factor for achieving successful manipulation in neuronal studies?

Temporal and spatial resolution considerations Signup and view all the answers

What effect do barbiturates have on GABA receptors?

They enhance GABA action by locking receptors in the open state. Signup and view all the answers

What is the main purpose of using a voltage clamp technique in cellular electrophysiology?

To fix the voltage at different levels to study membrane conductance. Signup and view all the answers

How does current clamp analysis contribute to the understanding of neuronal firing patterns?

It provides a simulation of normal neuronal behaviour. Signup and view all the answers

What is a characteristic of Ca2+ imaging techniques?

They allow for the visualization of calcium dynamics in live neurons. Signup and view all the answers

What distinguishes optogenetics from traditional methods of neuronal manipulation?

Optogenetics utilizes light to control neurons that have been genetically modified. Signup and view all the answers

DREADDs are used for which of the following applications in neuroscience?

To chemogenetically control neuronal activity with specific ligands. Signup and view all the answers

What is a significant outcome of Nav1.1 mutations in cortical interneurons?

Decreased excitability, leading to epilepsy. Signup and view all the answers

Which technique is primarily used to analyze voltage-dependent conductances?

Patch clamping. Signup and view all the answers

Which of the following compounds modulates GABA receptor activity by easing the opening of receptors?

Benzodiazepines. Signup and view all the answers

Which protein is associated with excitatory neural activity in optogenetics?

Channelrhodopsin ChR Signup and view all the answers

What is the role of the inhibitory protein Halorhodopsin (NpHR) in optogenetics?

Drives chloride into cells Signup and view all the answers

Which Ca2+ imaging technique allows depth visualization in living tissue?

Two-photon microscopy Signup and view all the answers

What therapeutic benefit does deep brain stimulation of the subthalamic nucleus (STN) provide?

Control of intention tremor Signup and view all the answers

Which of the following statements about optogenetics is true?

It employs light to manipulate neural activity. Signup and view all the answers

What effect does Archaerhodopsin have on cellular activity in optogenetics?

Promotes neuronal hyperpolarization Signup and view all the answers

How can chemogenetics and DREADDs influence neuronal activity?

By designing drugs that selectively activate or inhibit neurons Signup and view all the answers

What is the primary function of the neuronal cation channel in optogenetics?

Facilitating excitatory neurotransmission Signup and view all the answers

In the context of optogenetics, which channel specifically affects chloride ion flow?

Halorhodopsin Signup and view all the answers

What is the typical resting membrane potential for neurons?

-70 mV Signup and view all the answers

Which ion is primarily responsible for depolarizing the membrane during an action potential?

Na+ Signup and view all the answers

In extracellular recordings, what does the 'V' represent?

Voltage measured Signup and view all the answers

How does Ca2+ contribute to synaptic plasticity?

By facilitating neurotransmitter release Signup and view all the answers

Which of the following is NOT a potential application of optogenetics?

Enhancing gene expression in muscles Signup and view all the answers

What does Ca2+ imaging typically allow researchers to observe?

Single cell resolution imaging of activity patterns Signup and view all the answers

Which of the following accurately describes DREADDs in chemogenetics?

They mediate responses to specific designer drugs Signup and view all the answers

What measurement is critical to determine the speed of propagation in extracellular recordings?

Distance and time delay Signup and view all the answers

What cellular process negatively affects organelle motility?

Cell death Signup and view all the answers

Which ion's transduction is critical for converting electrical signals into chemical signals?

Ca2+ Signup and view all the answers

Study Notes

Chemogenetics and DREADDs

Designer Receptor Exclusively Activated by Designer Drugs (DREADDs) manipulate neuronal activity.
Human M3 muscarinic DREADD activates excitatory neurons via the Gq signaling pathway.
Human M4 muscarinic DREADD is coupled to the Gi signaling pathway, silencing neurons by opening K+ channels.
Clozapine-N-oxide (CNO) activates DREADDs without intrinsic activity.

Cell-Specific Targeting

Various neural cell classes express distinct protein sets for functional identity.
Promoters function like an IP address, enabling specific targeting of neuron classes expressing GluRA3 or GluRA4.

Advancements in Neuroscience Techniques

Neuronal communication primarily involves electrical signals, enabling early brain activity studies.
Innovative techniques foster scientific breakthroughs, tailoring methods to specific research questions.
Optical manipulation provides precise control at targeted locations with advantages in accessibility, temporal, and spatial resolution.
Non-invasive recording and stimulation technologies have become viable.

Optogenetics Overview

Optogenetics employs light to control neuronal activity.
Channelrhodopsin (ChR) serves as an excitatory cation channel, while halorhodopsin (NpHR) functions as an inhibitory Cl- pump.
Archaerhodopsin (Arch) acts as a H+ pump, influencing proton dynamics in cells.

Parkinson's Disease Research Insights

Optical dissection of neural circuitry offers new understandings of Parkinson's symptoms.
Deep brain stimulation of the subthalamic nucleus (STN) effectively manages intention tremors.
Investigates the role of local neurons versus fiber pathways in symptom control.

Voltage Clamp Technique

Developed by Hodgkin and Huxley, the voltage clamp technique revealed voltage-dependent ion conductances.
Facilitates analysis of active (non-linear) and passive (linear) conductances by fixing membrane voltage and observing ion currents.

Cellular Electrophysiology Techniques

Voltage clamp identifies voltage's impact on membrane conductance, characterized as “active” or “non-linear.”
Current clamp simulates natural neuronal behavior, aiding in analyzing firing patterns.

Patch Clamping Innovations

Patch clamp technique, pioneered by Sakmann and Neher, allows detailed study of individual ion channels and ensemble responses.
Provides insights into drug mechanisms, such as how barbiturates and benzodiazepines modulate GABA receptor actions.

Extracellular Recordings

Utilized to assess action potentials and local field potentials (LFPs) across brain systems.
Distant reference electrodes measure voltage changes indicating neuronal activity.

Calcium Imaging in Neurobiology

Ca2+ imaging offers single-cell resolution to track electrical activity and intracellular processes.
Calcium plays a critical role in various cellular functions like signaling, plasticity, and motility, accounting for its diverse implications in neuronal activities.

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Description

Explore the fascinating world of chemogenetics and Designer Receptors Exclusively Activated by Designer Drugs (DREADDs). This quiz covers the mechanisms of DREADDs, cell-specific targeting in neuronal studies, and the advancements in neuroscience techniques for manipulating neuronal activity. Test your knowledge on how these innovative methods are shaping our understanding of the brain.