The elusive crypt olfactory receptor neuron: evidence for its stimulation by amino acids and cAMP pathway agonists.
Crypt olfactory receptor neurons (ORNs) are a third type of chemosensory neuron along with ciliated and microvillous ORNs in the olfactory epithelium of fishes, but their functional role is still unknown. To investigate their odorant response properties and possible transduction pathways, we recorded crypt ORN activity with calcium imaging and the patch clamp technique in its cell-attached mode in combination with odorant and agonist stimulation. Bile salts and putative fish pheromones did not elicit responses with either method, but the cells frequently responded to amino acids, with excitation and intracellular calcium signals. 8Br-cAMP and IBMX plus forskolin stimulated over 40% of crypt ORNs and triggered calcium signals in a similar percentage. Furthermore, crypt ORNs were immunoreactive to an antiserum against adenylate cyclase III. Together, these data suggest the presence of a cAMP transduction pathway, which might transduce odorants such as amino acids.
Vielma
Alex
A
Centro de Neurociencia de Valparaíso, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Casilla 5029, Correo 4 2360102 Valparaíso, Chile.
Ardiles
Alvaro
A
Delgado
Luz
L
Schmachtenberg
Oliver
O
D000262:Adenylyl Cyclases / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000819:agonists / Q000494:pharmacology*; D005399:Fishes / Q000378:metabolism*; D007150:Immunohistochemistry; D008564:Membrane Potentials / Q000187:drug effects; D018034:Olfactory Receptor Neurons / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
D000596:Amino Acids; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D002118:Calcium