Olfactory transduction: cross-talk between second-messenger systems.
Chemosensory cilia of olfactory receptor neurons contain an adenylate cyclase which is stimulated by high concentrations of odorants. Cyclic AMP produced by this enzyme has been proposed to act as second messenger in olfactory transduction. Here we report that olfactory cilia contain calmodulin and that calmodulin potently activates olfactory adenylate cyclase by a mechanism additive to and independent from direct stimulation by odorants. Activation by calmodulin is calcium dependent and enhanced by GTP. Thus, olfactory transduction may involve a second-messenger cascade in which an odorant-induced increase in intracellular calcium concentration leads to activation of adenylate cyclase by calmodulin.
Anholt
R R
RR
Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710.
Rivers
A M
AM
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology*; D004789:Enzyme Activation; D006160:Guanosine Triphosphate / Q000378:metabolism; D009832:Olfactory Nerve / Q000187:drug effects / Q000201:enzymology*; D011892:Rana catesbeiana; D015290:Second Messenger Systems; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction
D002147:Calmodulin; D006160:Guanosine Triphosphate; D000262:Adenylyl Cyclases; D002118:Calcium