2 - Receptors 101 (generated)

These flashcards contain information about pharmacology, receptor types, their physiological roles, and pharmacological effects.

What is the typical molecular weight of a drug?

How much bigger are receptors compared to typical drugs?

At least 100 times bigger.

Name three important drugs that modify their targets covalently.

Aspirin, clopidogrel, omeprazole.

What is a superfamily in the context of proteins?

A broad grouping of proteins related to each other in structure and function.

Which is the biggest superfamily of proteins?

G protein-coupled receptors (GPCRs) with over 800 members.

How do superfamilies of proteins arise?

Through gene duplication and subsequent mutation.

What happens if a mutation is harmful or fatal to an organism?

The organism may not survive.

What can occur if an organism obtains a redundant copy of an essential gene?

The mutation in the 'spare' gene can take on a new function.

What are the two main groups of adrenoceptors?

α and β.

What are the subtypes of α adrenoceptors?

α1A, α1B, α1D, α2A, α2B, and α2C.

What are the subtypes of β adrenoceptors?

β1, β2, and β3.

What role does β1 receptors play in the heart?

They increase heart rate and force of contraction (inotropic effect).

Which drug blocks β1 receptors without affecting β2 much?

Atenolol.

What is B2 adrenoceptor's primary physiological role?

Produces dilation of airways.

Name an anti-asthma drug that activates β2 adrenoceptors.

Salbutamol (Ventolin).

What type of ion channels are nicotinic acetylcholine receptors (nAChRs)?

Pentameric ligand-gated ion channels (pLGIC).

What ions do nAChRs allow to permeate?

Na+ and K+, with some also allowing Ca2+.

What is the natural agonist for nAChRs?

Acetylcholine.

How do nAChRs affect muscle contraction?

They are responsible for fast excitatory transmission, triggering muscle contraction.

What neurotransmitter modulation occurs in the CNS due to nAChRs?

They modulate the release of dopamine, which makes nicotine addictive.

What is a pharmacological importance of nAChRs in skeletal muscle?

They are targets for drugs to block neuromuscular transmission during surgery.

What is a common psychoactive compound that can activate GABA-A receptors?

Muscimol.

What physiological role does GABA serve in the brain?

It is the main inhibitory transmitter.

What are the two classes of GABA receptors?

GABA-A (pLGIC) and GABA-B (G protein coupled).

What is a pharmacological use of GABA-A receptor modulation?

Used as targets for drugs such as general anesthetics and anti-anxiety medications.

What unique structural feature distinguishes ionotropic glutamate receptors (iGluRs) from pLGICs?

They are tetramers instead of pentamers.

Name the three families of iGluRs.

NMDA, AMPA, and kainate receptors.

What ions are iGluRs permeable to?

Na+, K+, and in some cases, Ca2+.

What is the primary excitatory neurotransmitter counterpart of GABA in the CNS?

Glutamate.

What is the main pharmacological importance of NMDA receptors?

They are important in learning and memory due to high calcium permeability.

What effect do general anesthetics have on iGluRs?

Inhibition of iGluRs.

What are receptor tyrosine kinases (RTKs)?

Large proteins with a single transmembrane domain that phosphorylate tyrosine residues.

How many RTKs are there in the human genome?

58 RTKs.

What is the importance of RTKs in cellular signaling?

They bind a wide range of peptide signaling molecules that regulate growth and metabolism.

What is the significance of HER2 receptors?

They regulate epithelial cell division and differentiation.

Name a monoclonal antibody targeting HER2 used in breast cancer.

Herceptin.

What are orphan receptors?

Nuclear receptors that have not yet been identified as having natural ligands.

Which hormone is the main agonist for glucocorticoid receptors?

Cortisol.

What is the physiological role of mineralocorticoid receptors?

Regulate salt and water balance, which controls blood pressure.

What can excessive aldosterone lead to?

Hyperaldosteronism causes fatigue, potassium loss, and high blood pressure.

What is an example of a drug that acts as an aldosterone antagonist?

Spironolactone.

What do thyroid hormone receptors regulate?

Metabolism and development, and they modulate heart rate.

What happens in hyperthyroidism?

Rapid heart rate, tremors, weight loss, and muscle weakness.

What can result from little thyroid hormone (hypothyroidism)?

Slow heart rate, weight gain, fatigue, and depression.

What is congenital hypothyroidism?

A condition leading to intellectual disability and physical impairments due to inadequate thyroid hormone production during early development.

Why do individuals with hyperthyroidism often need synthetic thyroid hormones?

Because treatment for hyperthyroidism destroys part or all of the thyroid gland.

How do nuclear receptors influence target gene transcription?

By binding to hormone response elements in DNA and altering the transcription rate.

What is the role of adapter proteins in RTK signaling?

They link RTKs to intracellular signaling pathways.

What is the physiological consequence of mutations in receptor proteins?

They can lead to altered receptor function or diseases.

What therapeutic applications are associated with synthetic glucocorticoids?

Treating asthma and rheumatoid arthritis.

What is the function of GABA-A receptors in pharmacology?

Targets for dampening brain activity through various drugs.

What type of synaptic transmission do nAChRs mediate?

Fast excitatory transmission.

Name a key physiological effect of nAChRs activation.

Muscle contraction.

What is the clinical application of drugs targeting GABA-A receptors?

Used in the treatment of anxiety and epilepsy.

How many nuclear receptors are identified in the human genome?

48, of which 10 are orphan receptors.

What is one consequence of insufficient cortisol production?

The body can become ill and potentially die if untreated.

What are the effects of hyperthyroidism on heart rate?

Increased heart rate (tachycardia).

What role do mineralocorticoid receptors play in fluid balance?

They regulate sodium and water balance, affecting blood pressure.

What is the mechanism through which GABA-A receptors contribute to brain inhibition?

By allowing more Cl- to enter the cell, hyperpolarizing it.

What are the pharmacological targets of nicotine?

nAChRs in the brain and skeletal muscle.

What effect do positive allosteric modulators have on receptors?

They enhance the receptor's function.

Which drugs are known to activate GABA-A receptors?

Diazepam and alcohol.

What is the largest family of G protein-coupled receptors?

Family A (adrenoceptors).

How does the binding of a ligand affect RTKs?

It dimerizes the receptors and activates their tyrosine kinase domain.

What is the physiological relevance of calcium-permeable receptors?

They are important for processes like synaptic plasticity and memory.

What is the general effect of general anesthetics on neurotransmission?

They inhibit excitatory neurotransmission.

What important function does iGluRs have in the CNS?

They mediate fast excitatory neurotransmission.

What impact does hyperaldosteronism have on potassium levels?

It causes loss of potassium (K+).

What is one main role of glucocorticoids in the body?

Regulating the immune response and inflammation.

What is the pharmacological significance of GABA in CNS?

It prevents excessive neuronal activity, contributing to calm and relaxation.

What can occur when iGluRs are excessively activated?

Excitotoxic brain damage.

What role does the dimerization of nuclear receptors play?

It allows them to move into the nucleus and regulate gene transcription.

What is the effect of binding of an agonist to a G protein-coupled receptor?

It activates intracellular signaling pathways.