Week 3 Flashcards
(19 cards)
What are the three main types of membrane-bound receptors?
Ion channel receptors, G-protein coupled receptors, and kinase-linked receptors
What are some common features of ion channels?
Common features of ion channels include: they are made up of 5 protein subunits, each with 4 transmembrane domains, and they allow ions to flow across the cell membrane
What is the effect of ligand binding on an ion channel receptor?
The binding of a messenger (ligand) to an ion channel receptor leads directly to ion flow across the cell membrane, resulting in a change in ion concentration within the cell.
What is the difference between excitatory and inhibitory ion channels?
Cationic ion channels such as those for K+, Na+, and Ca2+ are generally excitatory, while chloride channels are generally inhibitory
What are some examples of ligand-gated ion channels?
nicotinic acetylcholine receptors (nAChRs), GABA receptors, and glycine receptors
What is the natural ligand for the nicotinic acetylcholine receptor (nAChR)?
Acetylcholine
Is the nAChR a selective or non-selective ion channel?
The nAChR is a non-selective cation channel, meaning that it is permeable to several different positively charged ions like Na+, K+, and Ca2+
What is the effect of nicotine on the nAChR?
Nicotine is an agonist of the nicotinic acetylcholine receptor
What is the effect of muscarine on acetylcholine receptors?
Muscarine is a natural alkaloid that is one of the first systematically studied cholinomimetic substances
What is the natural ligand for the GABA receptor?
Gamma-aminobutyric acid (GABA).
What is the effect of GABA on its receptor?
GABA produces its effects through chloride current, which is generally inhibitory.
How do benzodiazepines affect the GABA receptor?
Benzodiazepines enhance the effect of GABA by binding to an allosteric binding site on the GABAA receptor
What is the effect of glycine on its receptor?
Glycine produces its effects through chloride current which is generally inhibitory
What is the effect of strychnine on glycine receptors?
Strychnine inhibits postsynaptic glycine receptors, particularly in the spinal cord
What is the effect of cocaine on sodium channels?
Cocaine blocks sodium channels
What is LD50?
The dose of a drug that is lethal in 50% of a population.
What is the difference between a drug’s potency and toxicity as shown in dose-response curves?
Two drugs can have the same LD50, but different slopes in their dose-response curves, indicating one drug is more toxic at lower doses than another
What are isomers?
Isomers are compounds with the same molecular formula but different structural formulas
What are enantiomers?
Enantiomers are a type of isomer which are stereoisomers that are non-superimposable mirror images of each other
