Question

A hypothetical mutant receptor binds poorly to the 5-HT₃ neurotransmitter, but has normal gating properties. (For instance, when exposed to an artificial agonist that has very high affinity for the receptor, the channel displays a current trace similar to that seen in Figure 3, top left.)

Would you expect this mutant receptor to have an EC₅₀ value higher or lower than 1 μM?

Would you expect the ∆∆G (EC₅₀) for this mutant receptor to be positive or negative?

How about its ∆∆G (c-t)?

Briefly explain each of your answers.

Answer 1

the 5-HT₃ neurotransmitter gate. it is an ion channel. it belongs to the family of receptor whose other members are GABA and glycine. it is made up of five subunits. each submit consists of extracellular membrane, transmembrane and intracellular membrane. extracellular domain is a ligand binding region. it is site for agonist and antagonist action.

EC₅₀ is the half maximal effective concentration. it is used to measure the drug effectiveness. it is a concentration of a drug which induces a response halfway  between baseline and maximue exposure time.

poorly binding receptors have less effectiveness in comparison with the high binding receptors. thus, EC50 value will be higher than 1M as its potential is low.

G value shows that more the value is negative, more will be the favourable reaction. since the binding is poor, thus, the value will be positive.