Neurotransmitters and Neuropharmacology

Flashcards covering neurotransmitter types, receptor mechanisms, synaptic transmission, and the neuropharmacology of various drugs including their effects, mechanisms of action, and addiction pathways.

How many provisional drug overdose deaths, mostly involving opioids, were recorded in the 12 months ending in the given period?

77,584

What is the mechanism by which tetanospasmin (associated with tetanus) causes generalized rigidity?

It binds irreversibly to the membrane at the synapse, blocking the release of glycine from axon terminals.

What are the four main steps of synaptic transmission?

1. Action potential arrives. 2. Vesicle fuses with plasma membrane. 3. Neurotransmitter is released into the synaptic cleft. 4. Neurotransmitter binds to the receptor.

Which drug was initially prescribed to Don, an accountant with Parkinson's disease, to restore dopamine levels?

Levodopa

What type of receptor is also known as a ligand-gated ion channel and directly opens an ion channel upon neurotransmitter binding?

Ionotropic receptor

What type of receptor recognizes the transmitter but activates a G-protein instead of directly opening an ion channel?

Metabotropic receptor

Approximately what percentage of all drugs act via metabotropic receptors?

75%

What is a drug called that initiates the normal effects of a receptor?

An agonist

What is a drug called that prevents a receptor from being activated by other ligands?

An antagonist

What drug mechanism involves serving as a precursor to a neurotransmitter to increase its synthesis?

Agonist - e.g., L-DOPA for dopamine

What drug mechanism involves blocking postsynaptic receptors?

Antagonist - e.g., curare, atropine for ACh

What drug mechanism involves blocking the reuptake of a neurotransmitter?

Agonist - e.g., cocaine for dopamine

Name the five main classes of neurotransmitters.

Amino acids, Monoamines, Soluble gases, Acetylcholine, Neuropeptides

What are the primary ionotropic receptors for glutamate?

AMPA receptor, NMDA receptor, Kainate receptor

What phenomenon occurs when neural injury, such as a stroke or head trauma, causes excess release of glutamate, leading to neuronal death?

Excitotoxicity

What is the most common inhibitory neurotransmitter in the brain?

GABA

Which type of GABA receptor is ionotropic and produces fast inhibitory effects?

GABA_A

What is the major inhibitory neurotransmitter in the spinal cord?

Glycine

What drug blocks glycine receptors and can cause violent convulsions?

Strychnine

What is the rate-limiting enzyme in catecholamine synthesis?

Tyrosine hydroxylase

What are the two major dopamine pathways in the brain?

Mesolimbocortical pathway (addiction, learning, schizophrenia) and Mesostriatal pathway (motor control)

The locus coeruleus is the origin of which neurotransmitter pathway involved in mood, arousal, and sexual behavior?

Norepinephrine

Raphe nuclei are the origin of which neurotransmitter pathway involved in sleep, sexual behavior, and anxiety?

Serotonin

What unique characteristic allows gas neurotransmitters like nitric oxide to function as retrograde transmitters?

They diffuse instantly back into the presynaptic neuron.

What are the two main types of acetylcholine (ACh) receptors?

Nicotinic and Muscarinic

Which type of ACh receptor is ionotropic, excitatory, and primarily found in peripheral muscles?

Nicotinic receptors

Which type of ACh receptor is metabotropic, can be excitatory or inhibitory, and is found in the CNS?

Muscarinic receptors

What group of peptides binds to opioid receptors to relieve pain and produces a feeling of well-being?

Endogenous opiates (e.g., enkephalins, endorphins, dynorphins)

What is a substance that indirectly affects transmitter release or receptor response, often by diffusing back into the presynaptic neuron?

Neuromodulator

How does caffeine increase catecholamine release and cause arousal?

It blocks the effect of adenosine, which normally inhibits catecholamine release via presynaptic autoreceptors.

What is the mechanism of action for typical neuroleptic (antipsychotic) drugs?

They are dopamine (D2) antagonists.

How do Monoamine Oxidase Inhibitors (MAOIs) act as antidepressants?

They prevent the breakdown of monoamines at the synapse, leading to their accumulation.

How do Selective Serotonin Reuptake Inhibitors (SSRIs) like Prozac and Zoloft work?

They cause serotonin to accumulate in synapses by blocking its reuptake into presynaptic axon terminals.

What class of drugs acts on GABA_A receptors to enhance the inhibitory effects of GABA via chloride influx, acting as potent tranquilizers?

Benzodiazepine agonists (anxiolytics)

What are the primary mechanisms by which barbiturates cause their depressant effects?

They block sodium channels on neurons and increase the flow of chloride ions across the neuronal membrane.

What is the biphasic effect of alcohol on behavior?

An initial stimulant phase (turning off cortical inhibition) followed by a depressant phase (sedation).

Which two major neurotransmitter systems does alcohol primarily affect, leading to sedation, anxiety reduction, and muscle relaxation?

It inhibits glutamate (excitatory) and acts at GABA_A receptors to increase GABA (inhibitory) binding.

What is the diagnosis for a comatose patient with tiny pupils who arouses within a minute after receiving naloxone?

Opiate overdose (e.g., Fentanyl overdose)

What is the active ligand in marijuana that binds to cannabinoid receptors in the brain?

THC (tetrahydrocannabinoid)

What are endocannabinoids, such as anandamide and 2-AG, known for in neurotransmission?

They are retrograde signaling molecules that diffuse back to activate cannabinoid receptors on nearby neurons and are synthesized 'on-demand'.

What is the primary psychoactive and addictive drug in tobacco, and what type of receptors does it activate?

Nicotine; it activates nicotinic ACh receptors.

How does cocaine produce its effects and high addictiveness?

It blocks monoamine transporters, especially dopamine, enhancing their effects, and enters the brain rapidly.

What is the mechanism of action for amphetamine and methamphetamine?

They block the reuptake and increase the release of catecholamines (dopamine, norepinephrine).

How do stimulant medications for ADHD, such as Adderall and Ritalin, work?

They increase activity in the prefrontal cortex and other regions, stimulating cortico-thalamic inhibitory networks to function better.

LSD is an agonist for which neurotransmitter's receptors, primarily in the visual cortex?

Serotonin

PCP (Phencyclidine) is an antagonist for which glutamate receptor?

NMDA receptor

What are the primary effects of Ecstasy (MDMA) on serotonin in the brain?

It blocks the serotonin reuptake transporter, prolonging the serotonin signal and causing excessive release of serotonin, and also causes oxytocin release.

What defines addiction as a brain disorder?

A chronic, usually relapsing brain disorder that causes compulsive drug use despite harmful consequences, involving brain changes that challenge self-control.

What is the difference between drug tolerance and sensitization?

Tolerance is decreased sensitivity to a drug with repeated use, while sensitization is increased sensitivity to a drug with repeated use.

What is the major reward system in the brain that is underlying the addictive effects of abused drugs?

The mesolimbocortical dopamine system (especially increased dopamine in the VTA).

What protein builds up in neurons with each drug exposure and perpetuates craving and high relapse rates in addicts by remodeling the nucleus accumbens?

Delta FosB (ΔFosB)

What type of pharmacological treatment for addiction mimics the drug's effects but is milder, often as a replacement?

Agonistic treatments (e.g., buprenorphine for opiate addiction, nicotine patch)

What type of pharmacological treatment for addiction blocks the drug's effects?

Antagonistic treatments (e.g., naltrexone for opiate addiction, baclofen for alcohol addiction)

What type of pharmacological treatment causes a violent reaction if the drug is used?

Aversive treatments (e.g., Antabuse for alcohol addiction)