Lecture 11 NROB60 Question And Answer

A comprehensive set of flashcards covering neurotransmitter systems, their roles, mechanisms, effects, and implications for behavior and mental health.

What is the primary function of neurotransmitters in neuronal communication?

Neurotransmitters are released from presynaptic terminals to communicate with postsynaptic targets.

What occurs when a neurotransmitter binds to its postsynaptic receptor?

It causes the opening or closing of specific postsynaptic ion channels.

What is the difference between EPSPs and IPSPs?

EPSPs (excitatory postsynaptic potentials) lead to depolarization and increase the likelihood of an action potential, while IPSPs (inhibitory postsynaptic potentials) lead to hyperpolarization and decrease the likelihood of an action potential.

What are the key components of neurotransmitter systems?

Presynaptic and postsynaptic elements of neurotransmitter systems, as well as ionotropic and metabotropic receptors.

What are the criteria for a substance to be classified as a classic neurotransmitter?

It must exist in the presynaptic terminal, be synthesized by the neuron, be released in significant quantities during an action potential, have specific receptors on postsynaptic membranes, produce changes in postsynaptic cells, and its release must be blocked to prevent influence on postsynaptic cells.

Name the three categories of small-molecule transmitters.

Acetylcholine, amino acids, and biogenic amines.

What is the role of amines?

Amines are organic compounds that contain nitrogen atoms and are responsible for various neurotransmitter functions.

What are amino acids in the context of neurotransmission?

They are the building blocks of proteins and also act as neurotransmitters.

What distinguishes biogenic amines from other neurotransmitters?

Biogenic amines are nitrogen-containing compounds with biological activity, including neurotransmitters like dopamine, norepinephrine, and serotonin.

What is Dale's Principle?

The idea that typically, one neuron releases one neurotransmitter, although there are exceptions.

What are GABAergic neurons?

Neurons that release GABA as their neurotransmitter.

What neurotransmitter is most commonly associated with fast synaptic transmission?

Glutamate.

What neurotransmitter is most commonly associated with inhibitory transmission?

GABA.

What is the role of GAD in neurotransmitter synthesis?

GAD (Glutamic Acid Decarboxylase) converts glutamate into GABA.

What mechanism terminates the activity of glutamate and GABA?

Reuptake into the presynaptic terminals and transport into glia cells.

Define agonist in the context of neurotransmitters.

An agonist is a drug that binds to a receptor and mimics the action of a neurotransmitter.

What is an antagonist in the context of neurotransmitter activity?

An antagonist is a drug that blocks or interferes with the action of a neurotransmitter.

What is the neurotransmitter mechanism of GABA A receptors?

GABA A receptors allow chloride ions to enter the cell, leading to inhibitory responses.

How is acetylcholine synthesized?

From Acetyl CoA and choline via the enzyme Choline acetyltransferase (ChAT).

What is the function of acetylcholinesterase?

It degrades acetylcholine in the synaptic cleft to terminate its action.

How does botulinum toxin affect neurotransmitter release?

It prevents vesicle fusion, leading to a decrease in ACh release.

What types of receptors exist for acetylcholine?

Nicotinic receptors (ionotropic) and muscarinic receptors (metabotropic).

What is the action of nicotinic acetylcholine receptors (nAChRs)?

They are fast and excitatory, primarily used by skeletal muscles.

What physiological role does norepinephrine play in the brain?

It influences arousal, attention, sleep, and feeding behavior.

What distinguishes the serotonergic system?

It originates from the raphe nuclei and is involved in mood, anxiety, and sleep control.

What are the four major types of histamine receptors?

H1, H2, H3, and H4, each with different distribution and function.

What effect do antihistamines generally have?

They block histamine's action, which can induce drowsiness.

How do channelrhodopsins work in optogenetics?

They are excitatory opsins activated by light to allow cations to enter the cell.

What is the purpose of Cre-dependent expression in optogenetics?

To express opsins only in specific cell populations that carry the Cre recombinase gene.

What is the significance of the substantia nigra in dopaminergic pathways?

It is crucial for motor control and implicated in Parkinson’s Disease.

How does serotonin affect mental health disorders?

Imbalances or dysfunctions in serotonin are implicated in various psychiatric disorders.

What is the rate-limiting step in catecholamine synthesis?

Tyrosine hydroxylase is the rate-limiting enzyme for all catecholamines.

What are the implications of dopamine loss in the mesostriatal pathway?

It is implicated in motor control issues associated with Parkinson's Disease.

What role does histamine play in the vestibular system?

It mediates reactivity and arousal in response to vestibular stimuli.

How do GABAB receptors differ from GABAA receptors?

GABAB receptors are metabotropic and mediate slow inhibitory effects, while GABAA receptors are ionotropic and mediate fast inhibition.

What drugs are often used to treat depression and how do they affect serotonin?

Drugs like Prozac inhibit the reuptake of serotonin, increasing its synaptic availability.

What type of neurotransmitter is involved in excitatory signal transmission in the central nervous system?

Glutamate is the principal excitatory neurotransmitter.

What is the function of transporters in neurotransmitter systems?

Transporters bring neurotransmitters back into presynaptic neurons post-release to terminate their action.

What are the consequences of chronic stress on neurotransmitter systems?

Chronic stress can disrupt neurotransmitter balance, leading to mood disorders.

Why is understanding neurotransmitter systems important for neuroscience research?

It helps in understanding the biochemical basis of behaviors and mental health conditions.

What distinguishes ionotropic receptors from metabotropic receptors?

Ionotropic receptors directly mediate synaptic transmission through ion flow, while metabotropic receptors signal through second messengers and lead to slower effects.

Which neurotransmitter is involved in the regulation of reward pathways in the brain?

Dopamine is instrumental in reward pathways.

What defines the characteristics of peptide neurotransmitters?

They are larger molecules composed of 3-36 amino acids and are typically slower acting than small-molecule transmitters.

What physiological effects does dopamine have on behavior?

It influences motivation, reward, and reinforcement.

How do common antidepressant medications function mechanistically?

By increasing the availability of serotonin in the synaptic cleft through reuptake inhibition.

Where are cholinergic neurons primarily located?

In the midbrain nuclei and basal forebrain nuclei.

Discuss the importance of the dopaminergic system in behavioral health.

It plays a significant role in motivation, reward, and has implications in mental health disorders.

What is an example of a neuromodulatory transmitter?

Dopamine, as it modulates neuronal activity rather than mediating fast synaptic transmission.

What physiological property is shared by all neurotransmitter receptors?

They can lead to various postsynaptic responses depending on receptor type and location.

What kind of cellular responses can GABA cause in the central nervous system?

GABA can induce inhibiting effects leading to hyperpolarization of postsynaptic neurons.

What two families can adrenergic receptors be classified into?

Alpha-adrenergic and beta-adrenergic receptors.

How does the cholinergic system relate to memory?

Loss of cholinergic neurons is linked to Alzheimer's disease and impairments in memory functions.

What drug mechanisms are explored in relation to neurotransmitter receptor interactions?

Agonists and antagonists can either mimic or block neurotransmitter action, influencing neural activity.

How do neurotransmitter vesicles differ in appearance?

Small, clear vesicles are associated with amino acids and some neurotransmitters, while dense-core vesicles are associated with peptide neurotransmitters.

What role does light play in optogenetic methods?

Light controls neuronal activity, allowing precise manipulation for experimental purposes.

How are neuropeptides distinguished from small-molecule transmitters?

Neuropeptides are larger and packaged in large, dense-core vesicles.

What is the significance of understanding neurotransmitter systems for therapies?

It aids in the development of pharmacological treatments for various neurological and psychological disorders.

What is the primary neurotransmitter used at the neuromuscular junction?

Acetylcholine is the primary neurotransmitter for muscle contraction.

How does histamine affect sleep and wakefulness?

Histamine promotes wakefulness and arousal in the central nervous system.

What outcome results from nitric oxide in neurotransmission?

Nitric oxide acts as a retrograde messenger that can influence the release of other neurotransmitters.

What is the underlying mechanism by which glaucoma treatments affect neurotransmitter systems?

They often aim to modulate neurotransmitter receptors to reduce intraocular pressure.

What is the impact of excitotoxicity in neural systems?

Excessive stimulation by neurotransmitters like glutamate can lead to neuronal death.

What effect does increased serotonin have on mood?

Increased serotonin levels typically improve mood and reduce symptoms of depression.

How do neuropeptides participate in pain regulation?

Neuropeptides like substance P transmit pain signals and modulate pain perception.

Name two main types of GABA receptors and their general functions.

GABA A receptors are ionotropic and mediate fast inhibition; GABA B receptors are metabotropic and mediate slow inhibition.

What role does the locus coeruleus play in neurotransmitter pathways?

It is a primary source of norepinephrine projections influencing arousal and attention.

How might neurotransmitter imbalances contribute to mental health disorders?

Imbalances can affect mood, anxiety, and other cognitive functions, contributing to disorders like depression or anxiety.

Describe the role of optogenetics in understanding neuronal circuits.

Optogenetics allows for specific manipulation of neurons to test their role in behavior, enhancing the understanding of neural circuit functions.

What are the synaptic effects of enduring stress on neurotransmitter systems?

Chronic stress may lead to dysregulation of neurotransmitter systems, especially serotonin and catecholamines.

How can the study of acetylcholine (ACh) help to understand synaptic transmission?

ACh serves as a model for studying neurotransmitter lifecycle, from synthesis to degradation, influencing muscle contraction and brain functions.

What are potential therapeutic implications of targeting neurotransmitter systems?

Targeting specific neurotransmitter receptors can lead to treatments for various neurological disorders, including anxiety, depression, and schizophrenia.

Discuss the importance of understanding neurotransmitter receptor subtypes.

Different receptor subtypes determine the pharmacological effects of drugs and influence specificity in treatment.

How can neurotransmitters affect cellular signaling in the brain?

Neurotransmitters can initiate various signaling pathways that influence gene expression, cellular growth, and metabolism.

Why are peptide neurotransmitters slower acting than small-molecule transmitters?

They require complex processing and release mechanisms due to their larger size.

What is the relationship between neurotransmitter systems and behavior?

Neurotransmitter systems are foundational to understanding the biochemical basis of behaviors and mental health.

Identify one potential effect of drug abuse on neurotransmitter systems.

Drug abuse can lead to long-term changes in neurotransmitter signaling pathways, contributing to addiction and withdrawal symptoms.

What is the significance of using viral vectors in optogenetic experiments?

Viral vectors allow for precise delivery of opsins to targeted neurons, enabling controlled activation.

What neurotransmitter acts in the regulation of appetite and feeding behavior?

Norepinephrine plays a role in appetite control and feeding behaviors.

What is one mechanism through which antidepressants affect serotonin?

They often inhibit the reuptake of serotonin, increasing its availability in the synaptic cleft.

What roles do ionotropic and metabotropic receptors play in neurotransmission?

Ionotropic receptors mediate rapid responses through ion channel opening, while metabotropic receptors initiate slower, longer-lasting effects through second messenger systems.

What is the clinical significance of cholinergic systems in Alzheimer’s disease?

Cholinergic neuron loss is associated with memory impairments in Alzheimer's, making it a target for therapeutic intervention.

How do neuromodulators differ from classical neurotransmitters?

Neuromodulators generally have broader, more diffuse effects on neuronal activity rather than direct synaptic transmission.

How does the functional diversity of neurotransmitters contribute to nervous system function?

Diverse neurotransmitters allow for complex signaling and regulation across various brain regions, influencing behavior and physiology.

What experimental advantages does optogenetics offer over traditional methods?

It provides precise, specific control over neuronal activity, allowing for clearer causal relationships between neural circuits and behavior.

What is the effect of chronic drug exposure on neurotransmitter receptor sensitivity?

Chronic exposure can result in receptor desensitization or upregulation, altering the efficacy of neurotransmitter signaling.

Explain the role of electrical stimulation in neuroscience research.

It helps map neuronal pathways and assess the functional roles of specific brain regions.

How does methionine influence neurotransmitter synthesis?

Methionine serves as a methyl donor in the synthesis of neurotransmitters like dopamine and serotonin.

What is a common feature of all neurotransmitter receptors?

They generate cellular responses through conformational changes upon neurotransmitter binding.

Describe one consequence of neurotransmitter receptor overactivation.

Overactivation can lead to excitotoxicity, which may result in neuronal damage or death.

What receptors mediate the effects of dopamine in the brain?

Dopamine acts on five subtypes of metabotropic receptors (D1-D5), each with distinct functions.

What is the role of norepinephrine in the body's stress response?

Norepinephrine is involved in the fight-or-flight response, increasing heart rate and blood flow.

How do GABAB receptors contribute to synaptic inhibition?

They are activated by GABA and inhibit neuronal activity through second messenger pathways.

What mechanisms are involved in neurotransmitter reuptake?

Transport proteins help bring neurotransmitters back into the presynaptic neuron for recycling or degradation.

What factors influence the release of neurotransmitters in the brain?

Action potentials, calcium influx, and the presence of specific signaling molecules.

What is the significance of GABAergic inhibition in mental health?

Balanced GABAergic transmission is essential for mood stability and anxiety regulation.