This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Odorant molecule binds to which receptors? 
Select and explain. 
A. C AMP, B. G protein coupled membrane receptors, C. JAK kinase pathway, D. NF receptors
B: G protein coupled membrane receptors
Answer: B: G protein coupled membrane receptors 
Explanation: Ans. is 'b' i.e., G protein coupled membrane receptors [Rel Ganong 23'd/e ch 15; Guyton 12h/e p. 649)Odour receptors are G-protein coupled receptors.Receptor-ligand interaction (adsorption of odorant molecules to the cilia of receptors) results in opening of Na+ channel through second messenger cAMP.Opening of Na* channels result in Na* influx and generation of action potentials.