PSY2000

What is the difference between ionotropic and metabotropic receptors?

Ionotropic receptors are ligand-gated ion channels that mediate fast synaptic transmission, while metabotropic receptors are G-protein coupled receptors that mediate slower, longer-lasting effects through second messengers.

What is the most common excitatory neurotransmitter?

Glutamate

What is the most common inhibitory neurotransmitter?

GABA (gamma-aminobutyric acid)

Where are neurotransmitters made?

They are made within neurons.

What nuclei in the brainstem and forebrain are responsible for serotonin production?

The raphe nuclei

What nuclei are responsible for dopamine production?

The substantia nigra and the ventral tegmental area

What nuclei are responsible for acetylcholine production?

The basal forebrain and the brainstem nuclei

What are the initial precursors for dopamine, norepinephrine, epinephrine, serotonin, and acetylcholine?

They come from dietary sources.

What neurotransmitters share a pathway of synthesis and what are they collectively called?

Dopamine, norepinephrine, and epinephrine share a synthesis pathway and are collectively called catecholamines.

What neurotransmitters are included in the group 'monoamines'?

Dopamine, norepinephrine, epinephrine, and serotonin.

Can a neuron respond to more than one neurotransmitter?

Yes.

Can a neuron release more than one neurotransmitter?

Yes.

What are the three ways to remove a neurotransmitter from a synapse?

Reuptake by the presynaptic neuron, enzymatic degradation, and diffusion away from the synaptic cleft.

Define agonist and provide an example.

An agonist is a substance that activates a receptor to produce a biological response; for example, morphine is an agonist of opioid receptors.

Define antagonist and provide an example.

An antagonist is a substance that blocks or dampens the biological response by binding to a receptor without activating it; for example, naloxone is an antagonist of opioid receptors.

How do psychotropic drugs affect neurotransmission?

They can alter neurotransmitter systems by blocking receptors, increasing neurotransmitter release, or inhibiting reuptake.

Acetylcholine

Synthesis nucleus: Basal forebrain; Division of brain: Forebrain; Functions: Autonomic NS, Somatic NS, Cortical Activation.

Dopamine

Synthesis nucleus: Substantia Nigra, Nucleus Accumbens; Functions: Reward, Movement, Cognition, Reinforcement.

Serotonin

Synthesis nucleus: Medulla, pons, midbrain; Functions: Sympathetic NS, Sexual Behavior, Appetite, Locus coeruleus.

Norepinephrine

Synthesis nucleus: Midbrain & Brainstem; Division of brain: Forebrain & Spinal cord; Functions: Anxiety, Mood, Sleep.

Ionotropic receptor

Contains ion channel.

Metabotropic receptor

G-protein attached intracellularly.

Both

Activated when neurotransmitter binds.

Glial cells

Remove neurotransmitters from the synapse.

Enzymatic degradation

Blocks enzyme that breaks down Acetylcholine.

Reuptake

Presynaptic terminal reabsorbs neurotransmitters.

Peptide neurotransmitters

Examples: Endorphins, enkephalin, Oxytocin, Vasopressin.

Catecholamines

Examples: Dopamine, Norepinephrine, Epinephrine.

Monoamines

Examples: Dopamine, Serotonin, Norepinephrine.

Gas neurotransmitter

Example: Nitric Oxide.

Why must gases be produced on demand?

Because they can't be stored in vesicles.

Agonist

A drug that mimics or increases the effects of a neurotransmitter.

Antagonist

A drug that blocks the effects of a neurotransmitter.

What is heritability?

Heritability is a measure of how much of the variation in a trait can be attributed to genetic factors, often studied through twin and adoption studies.

What do twin studies reveal about heritability?

Twin studies show that if monozygotic twins exhibit more resemblance for a trait compared to dizygotic twins, it suggests a higher heritability for that trait.

What are some environmental influences on traits with high heritability?

Examples include studies on maze-bright and maze-dull rats, human intelligence variations, and the effects of phenylketonuria (PKU).

What is the difference between genetics and epigenetics?

Genetics focuses on the inheritance of genes, while epigenetics studies how gene expression is regulated by external factors without altering the DNA sequence.

What are sex-limited genes?

Sex-limited genes are expressed in only one sex, while sex-linked genes are located on sex chromosomes and can affect both sexes.

What is the process of transcription?

Transcription is the process of copying a segment of DNA into mRNA, occurring in the nucleus of the cell.

What is the process of translation?

Translation is the process of synthesizing proteins from mRNA, occurring in the cytoplasm at ribosomes.

How do mRNA vaccines work?

mRNA vaccines work by introducing a piece of mRNA that encodes a viral protein, prompting the immune system to recognize and respond to the virus.

What are some epigenetic modifications?

Epigenetic modifications include methylation, demethylation, and acetylation, which can affect gene activity and expression.

How does methylation affect gene activity?

Methylation typically represses gene activity, preventing transcription and thus reducing the expression of the gene.

What experiences can cause epigenetic modifications?

Experiences such as stress, diet, and exposure to toxins can lead to epigenetic modifications.

Who can be affected by epigenetic modifications?

Epigenetic modifications can affect the individual in whom they occur, their children, and potentially subsequent generations.

What does a 60% concordance in MZ twins and 20% in DZ twins suggest about heritability?

It suggests high heritability.

List three heritable physical traits.

Height, hair color, eye color.

What does a 30% concordance in both MZ and DZ twins indicate about heritability?

It suggests low heritability.

What does it mean if a child resembles biological parents more than adoptive parents?

It indicates high heritability.

What does it mean if a child resembles adoptive parents more than biological parents?

It suggests low heritability.

What is the significance of breeding 'maze bright' rats?

It suggests maze running ability is highly heritable.

What does raising genetically 'maze dull' rats in an enriched environment suggest?

It suggests that the environment can influence the expression of traits.

What is the major problem with interpreting data from twin and adoption studies?

Genetic and environmental influences are dependent on one another, making it hard to identify the true cause of a trait.

What is a biochemical method of studying heritability?

Identifying genes more prevalent in a group of people with the same behavioral trait.

What is PKU and how does it illustrate a nature-nurture interaction?

PKU is Phenylketonuria, a metabolic disorder that only manifests when genetically predisposed individuals consume a diet high in phenylalanine.

What do heritability studies on intelligence in children from different SES families suggest?

They suggest that environmental factors influence the heritability of intelligence.

What effect does DNA methylation have on gene expression?

It tightens DNA, making it harder to express a gene.

What is another epigenetic modification that can change gene expression?

Histone modification.

What is a phenotype?

An observable trait.

What is a coding sequence of a chromosome?

A gene.

What are sex-linked genes?

Genes located on the X or Y chromosome.

List three experiences that can lead to epigenetic alterations.

Stress, environmental toxins, immunotherapy.

What is an allele?

A version of a gene.

What does homozygous mean?

A pair of genes that are exactly the same.

What does heterozygous mean?

A pair of genes that differ slightly.

What is a dominant gene?

A gene that shows an effect in both homozygous and heterozygous conditions.

What is a recessive gene?

A gene that only shows its effect in the homozygous condition.

Why are X-linked genes expressed more in genetic males?

Because males have one X-chromosome, while females have two, which can mask recessive traits.

What is transcription?

The process of making a copy of the coding sequence of DNA, resulting in mRNA.

Where is mRNA produced and where does it move to?

mRNA is produced in the nucleus and moves to the cytoplasm.

What is translation?

The process where ribosomes read the sequence of mRNA to build a peptide or protein.

What are the building blocks of peptides and proteins?

Amino acids.

What are the defining characteristics of a drug?

A drug is a chemical substance that alters physiological functions in the body.

What is a psychoactive drug?

A psychoactive drug is a substance that affects the mind, altering mood, perception, or consciousness.

Which route of administration gets a drug to the brain the fastest?

Intravenous (IV) administration.

Define agonists and provide an example.

Agonists are substances that activate receptors to produce a biological response; for example, morphine is an agonist at opioid receptors.

Define antagonists and provide an example.

Antagonists are substances that block or dampen a biological response by binding to receptors; for example, naloxone is an antagonist at opioid receptors.

What is binding affinity?

Binding affinity refers to the strength of the interaction between a drug and its receptor.

Which typically has a high binding affinity for receptors, neurotransmitters or drugs?

Neurotransmitters typically have a high binding affinity for receptors.

What is a dose-response curve?

A dose-response curve is a graph that shows the relationship between the dose of a drug and the magnitude of its effect.

What is the therapeutic index?

The therapeutic index is the ratio between the toxic dose and the therapeutic dose of a drug, indicating its safety margin.

Compare benzodiazepines and barbiturates.

Both are GABA receptor agonists; benzodiazepines have a wider therapeutic index, making them safer than barbiturates.

What are the effects of benzodiazepines?

Benzodiazepines produce anxiolytic and sedative effects by enhancing inhibitory neurotransmission.

What is an example of a common benzodiazepine?

Xanax (alprazolam) or Valium (diazepam).

Define tolerance.

Tolerance is a phenomenon where increasing doses of a drug are required to achieve the same effect.

Define sensitization.

Sensitization is an increased response to a drug following repeated exposure.

What is cross-tolerance?

Cross-tolerance occurs when tolerance to one drug results in tolerance to another drug, often within the same class.

What is conditioned drug tolerance?

Conditioned drug tolerance refers to a decrease in drug effects when the drug is administered in the same environment where it was previously used.

What is the mesolimbic pathway?

The mesolimbic pathway, also known as the reward/reinforcement pathway, connects the VTA to the nucleus accumbens and is crucial for the experience of pleasure.

What activates the mesolimbic pathway?

Natural reinforcers such as food, sex, and social interactions activate the mesolimbic pathway.

What is the effect of dopamine release in the nucleus accumbens?

Dopamine release signals pleasure and reinforces behaviors associated with rewards.

How do cocaine and amphetamines increase dopamine transmission?

Cocaine blocks dopamine reuptake, while amphetamines promote dopamine release, both increasing dopamine levels in the nucleus accumbens.

What is the effect of opiates in the locus coeruleus?

Opiates inhibit activity in the locus coeruleus, reducing stress and pain perception.

Where does nicotine act in the nervous system?

Nicotine acts on nicotinic acetylcholine receptors in both the central and peripheral nervous systems.

What are some cognitive effects of nicotine?

Nicotine enhances alertness, attention, and cognitive performance.

What neurotransmitter systems are responsible for alcohol's reinforcing effects?

Alcohol primarily affects the GABA and dopamine systems, contributing to its reinforcing and pleasurable effects.

What neurotransmitter system do LSD, ecstasy, and psilocybin affect?

These substances primarily affect the serotonin system.

What hormones does ecstasy stimulate?

Ecstasy stimulates hormones like oxytocin (related to social bonding) and vasopressin (related to water balance).

Describe the 4 main models of addiction.

The four main models are the moral model, disease model, psychological model, and socio-cultural model, each with its own weaknesses.

What experiences can cause cravings or relapse?

Stress, environmental cues, and exposure to drug-related stimuli can trigger cravings and relapse.