PSYU2236 W5 | Neurotransmitter Receptors and Drug Effects

Questions and Answers

What is the primary function of agonists in relation to receptors?

They have no effect on neuronal communication.

They block receptor activity.

They prevent neurotransmitter release.

They bind to receptors and enhance neuron activity. (correct)

What distinguishes antagonists from agonists?

Antagonists increase neurotransmitter availability.

Antagonists have no effect on the receptor.

Antagonists bind to receptors but do not activate them. (correct)

Antagonists enhance neuronal firing.

Which of the following statements is true regarding the diversity of receptors?

Receptors can exist without neurotransmitters. (correct)

All receptors have identified neurotransmitters.

Receptors only bind to one specific type of neurotransmitter.

There are no classifications for receptors.

Which neurotransmitter does not typically interact with a receptor type listed in the diversity of receptors?

Norepinephrine with NMDA receptors. Signup and view all the answers

Which of the following receptor types is specifically identified as GABA-related?

GABA-A Signup and view all the answers

Which amino acid is specifically present only in GABA cells?

GABA Signup and view all the answers

What is the primary function of GABA transaminase?

To break down GABA Signup and view all the answers

What happens when glutamate levels are not effectively reduced by glial cells?

There is an increase in programmed cell death Signup and view all the answers

How does GABA originate in the nervous system?

From glutamate via a specific enzyme Signup and view all the answers

What is a consequence of high glutamate levels in the brain?

Neurotoxic effects leading to neuron death Signup and view all the answers

What is the primary function of histamine in the brain?

Inducing wakefulness Signup and view all the answers

Which amino acid is the precursor for the synthesis of catecholamines?

Tyrosine Signup and view all the answers

Which neurotransmitter is primarily associated with the regulation of circadian rhythms?

Melatonin Signup and view all the answers

Where are the cell bodies of dopamine and noradrenaline primarily located?

Ventral tegmental area and substantia nigra Signup and view all the answers

Which enzyme is responsible for converting Tyrosine to L-DOPA?

Tyrosine hydroxylase Signup and view all the answers

What is the effect of anti-histamines on the brain?

They cause sleepiness Signup and view all the answers

Which neurotransmitter is specifically mentioned as projecting dopamine towards the nigrostriatal system?

Dopamine Signup and view all the answers

What role do catecholamines play in the nervous system?

Facilitating emotional responses Signup and view all the answers

What is the major role of acetylcholine in the nervous system?

Perceptual learning and memory Signup and view all the answers

Which statement accurately describes the nature of acetylcholine?

It is predominantly excitatory. Signup and view all the answers

What processes does acetylcholine modulate?

Memory and REM sleep Signup and view all the answers

Which of the following neurotransmitters is primarily excitatory alongside acetylcholine?

Noradrenaline Signup and view all the answers

What is cholinergic neurotransmission most associated with?

Memory and cognitive functions Signup and view all the answers

Where are the cell bodies of acetylcholine neurons primarily located?

In the brain and spinal cord Signup and view all the answers

What is the precursor for acetylcholine synthesis?

Acetyl coenzyme A Signup and view all the answers

Which process is NOT associated with acetylcholine?

Mediating sleep without REM Signup and view all the answers

What are the positive psychotic symptoms primarily associated with in schizophrenia?

Increased dopamine in the nucleus accumbens Signup and view all the answers

Which receptor type is generally involved in producing positive symptoms of schizophrenia?

D2 receptors Signup and view all the answers

What is the primary function of a dopamine D2 receptor antagonist in schizophrenia?

To block dopamine's action at D2 receptors Signup and view all the answers

What cognitive effect is linked to hypofrontality in schizophrenia?

Cognitive deficits Signup and view all the answers

How does increased dopamine impact the functioning of the dorsal striatum?

It weakens the filtering process Signup and view all the answers

What is the main role of mesocorticolimbic dopamine system in relation to schizophrenia?

It produces both positive and negative symptoms Signup and view all the answers

What happens to D2 receptors when neuroleptics bind to them?

They cannot bind to anything Signup and view all the answers

Which condition is primarily linked to hypofrontality?

Schizophrenia Signup and view all the answers

Study Notes

Neurons and Neurotransmitters

Neurotransmitter release binds to receptors on adjacent neurons, signaling them.
Agonists enhance receptor activity, while antagonists block it.

Receptor Diversity

Numerous types of receptors exist, including:
- µ, o, K
- Nicotinic and Muscarinic receptors
- 5-HT (serotonin) receptors, NMDA, AMPA
- GABA receptors (A & B)
- Some receptors lack identified neurotransmitters.

Anti-histamines and Sleep

Anti-histamines can cause drowsiness due to their effects on neurotransmitter systems.

Monoamine Neurotransmitters

Key monoamines include:
- Catecholamines: Dopamine, Noradrenaline (Norepinephrine), and Adrenaline (Epinephrine).
- Indolamines: Serotonin and Melatonin, involved in sleep-wake cycles.

Dopaminergic Pathways

Dopamine projects from the Substantia Nigra (SN) to the nigrostriatal system and from the Ventral Tegmental Area (VTA) to the mesolimbic system.
Approximately 14 dopaminergic cell projection routes exist around the brain.

Catecholamine Synthesis

Derived from Tyrosine, an amino acid acquired through diet or synthesized from Phenylalanine.
Tyrosine Hydroxylase (TH) is a critical enzyme for dopamine production.

Amino Acid Neurotransmitters

Common amino acids include Glutamate, Aspartate, Glycine, and GABA.
GABA is synthesized from Glutamate through Glutamic Acid Decarboxylase (GAD).

Neurotransmitter Metabolism

GABA is modified by GABA transaminase and can be recycled with transporters.
Excess Glutamate can be neurotoxic, requiring glial cells to regulate levels to prevent neuron death (apoptosis).

Acetylcholine Functions and Synthesis

Acetylcholine (ACh) primarily serves excitatory roles in memory and cognitive functions.
Synthesized from Acetyl Coenzyme A and transported into vesicles.

Dopamine Hypothesis in Schizophrenia

Cognitive deficits linked to decreased dopamine in the prefrontal cortex (hypofrontality).
Positive symptoms arise from increased dopamine in the Nucleus Accumbens (mesolimbic pathway).
D1 and D2 receptors: D2 receptor activity correlates with schizophrenia's positive symptoms. Using D2 antagonists can mitigate psychotic effects.

Neuroleptic Drugs

Neuroleptics interact with D2 receptors, preventing their activation and reducing psychotic symptoms.
Side effects manifest due to their influence on various neurological pathways.

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Description

Explore the intricacies of neurotransmitter receptors and how different drugs interact with them. This quiz covers the concepts of agonists and antagonists along with various receptor types. Test your knowledge on the diversity of receptors and their functions.