Mechanisms for Termination of Olfactory Responses in ORNs Include

Question

Mechanisms for termination of olfactory responses in ORNs include: A) inhibition of the CNG channel by Ca²⁺/calmodulin. B) inhibition of the phosphodiesterase PDE1c by Ca²⁺/calmodulin. C) conversion of ATP to cAMP. D) activation of ACIII by CaMKII. E) All of the above

Accepted Answer

Ca²⁺/Calmodulin binds directly to the CNG and inhibits it, stopping the influx of cations. It also activates the phosphodiesterase PDE1c, which in turn hydrolyzes cAMP to AMP. CaMKII phosphorylates ACIII, which inactivates it and prevents conversion of additional ATP to cAMP.