Neurotransmitters and CNS

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Questions and Answers

What is the primary effect of the release of inhibitory neurotransmitters, such as GABA or glycine, on the postsynaptic cell membrane?

Hyperpolarization and decreased neural excitability (correct)

Decreased permeability to potassium ions

Increased permeability to sodium ions

Depolarization and increased neural excitability

What is the result of the combined effects of EPSP and IPSP on a neuron?

Either increased or decreased likelihood, depending on the strength of the EPSP and IPSP

No effect on action potential generation

Increased likelihood of action potential generation

Decreased likelihood of action potential generation (correct)

What is the effect of acetylcholine binding to its receptor on the neuron?

No effect on neural excitability

Depolarization and increased neural excitability (correct)

Hyperpolarization and decreased neural excitability

Either hyperpolarization or depolarization, depending on the strength of the signal

What is the result of an influx of chloride ions (Cl−) and efflux of potassium ions (K+) on the neuron?

Hyperpolarization and decreased neural excitability Signup and view all the answers

What is the effect of Na+ entry into the neuron?

Depolarization and increased neural excitability Signup and view all the answers

What is a characteristic of neurotransmitters binding to their receptors on the postsynaptic cell membrane?

They can cause either depolarization or hyperpolarization, depending on the specific receptor and neurotransmitter Signup and view all the answers

What is the result of stimulation of inhibitory neurons on the postsynaptic cell?

Decreased likelihood of action potential generation Signup and view all the answers

What is a characteristic of the combined effects of EPSP and IPSP on a neuron?

Can result in either depolarization or hyperpolarization, depending on the strength of the EPSP and IPSP Signup and view all the answers

What is the overall action of neurotransmitters on a neuron?

Summation of individual actions of various neurotransmitters Signup and view all the answers

What is the characteristic of neuronal tracts in the CNS?

Chemical coding of specific neuronal tracts Signup and view all the answers

Which disease is characterized by the progressive loss of selected neurons in discrete brain areas?

All of the above Signup and view all the answers

What is the result of the progressive loss of selected neurons in discrete brain areas?

Characteristic disorders of movement, cognition, or both Signup and view all the answers

What is the role of GABA receptors in the postsynaptic neuron membrane?

Closing of chloride channels Signup and view all the answers

What is the consequence of an empty receptor in the postsynaptic neuron membrane?

The receptor is inactive and the chloride channel is closed Signup and view all the answers

What is the potential therapeutic approach for neurodegenerative diseases?

Selective modulation of certain neural pathways Signup and view all the answers

What is the common characteristic of neurodegenerative diseases mentioned in the text?

Progressive loss of selected neurons in discrete brain areas Signup and view all the answers

Which of the following medications is not used to treat Alzheimer's disease?

Ropinirole REQUIP Signup and view all the answers

What is the primary function of neurotransmitters in the CNS?

To diffuse across the synaptic space and bind to specific receptors Signup and view all the answers

Which of the following medications is used to treat Parkinsonian symptoms?

Ropinirole REQUIP Signup and view all the answers

What is a key difference between neurons in the peripheral ANS and those in the CNS?

The CNS has a more complex neural network Signup and view all the answers

Which of the following medications is used to regulate dopamine levels in the brain?

Rasagiline AZILECT Signup and view all the answers

What is the main cause of neurotransmitter imbalance in Alzheimer's disease?

Acetylcholine imbalance Signup and view all the answers

Which of the following medications is used to treat dementia-related symptoms?

Galantamine RAZADYNE Signup and view all the answers

What is the primary mechanism of action of dopamine agonists in the treatment of Parkinson's disease?

Mimicking the action of dopamine on receptors Signup and view all the answers

Study Notes

Neurotransmission in the CNS

Neurotransmitters are not uniformly distributed in the CNS, but are localized in specific clusters of neurons.
The axons of these neurons may synapse with specific regions of the brain, making many neuronal tracts seem to be chemically coded.
This chemical coding may offer greater opportunity for selective modulation of certain neural pathways.

Neurodegenerative Diseases

Neurodegenerative diseases of the CNS include Parkinson's disease, Alzheimer's disease, MS, and ALS.
These diseases are characterized by the progressive loss of selected neurons in discrete brain areas, resulting in characteristic disorders of movement, cognition, or both.

Inhibitory Neurotransmission

Stimulation of inhibitory neurons releases neurotransmitter molecules, such as GABA or glycine, which bind to receptors on the postsynaptic cell membrane.
This causes a transient increase in the permeability of specific ions, such as potassium (K+) and chloride (Cl−).
The influx of Cl− and efflux of K+ cause a weak hyperpolarization, or IPSP, that moves the postsynaptic potential away from its firing threshold.

Excitatory Neurotransmission

Binding of the excitatory neurotransmitter, acetylcholine, causes depolarization of the neuron.
Entry of Na+ depolarizes the cell and increases neural excitability.

Combined Effects of EPSP and IPSP

Most neurons in the CNS receive both EPSP and IPSP input.
Several different types of neurotransmitters may act on the same neuron, but each binds to its own specific receptor.

Parkinson's Disease

Overview of Parkinson's disease: a neurodegenerative disease characterized by the progressive loss of selected neurons in discrete brain areas.

Drugs for Neurodegenerative Diseases

Medications for Parkinson's disease: Procyclidine (KEMADRIN), Rasagiline (AZILECT), Ropinirole (REQUIP), Rotigotine (NEUPRO), Selegiline (ELDEPRYL, ZELAPAR), Tolcapone (TASMAR), Trihexyphenidyl (ARTANE)
Medications for Alzheimer's disease: Donepezil (ARICEPT), Galantamine (RAZADYNE), Memantine (NAMENDA), Rivastigmine (EXELON)

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Description

This quiz covers the role of neurotransmitters in the central nervous system, their distribution in specific clusters of neurons, and their effect on brain regions. It delves into the actions of neurotransmitters on neurons and their synapses.