Single odors differentially stimulate dual second messenger pathways in lobster olfactory receptor cells

Abstract

Quench-flow measurements are used to determine the subsecond kinetics of odor-induced changes in second messenger concentrations in lobster olfactory receptor neurons. Individual odors transiently and differentially increase the production of both adenosine cAMP and inositol 1,4,5-trisphosphate (IP3) within 50 msec of odor stimulation. The ability of two different odors to stimulate cAMP and IP3 correlates with the odors' ability to excite and inhibit receptor cells physiologically. These results strengthen the proposition, heretofore based largely on evidence from cultured cells, that dual second messenger pathways mediate excitatory and inhibitory input to lobster olfactory receptor cells.

Molecular Cloning of a Lobster Gαq Protein Expressed in Neurons of Olfactory Organ and Brain

“…both. Previous studies have implicated the InsP3 pathway and Ga,4 in excitatory olfactory transduction in lobsters, especially in P. argus (Fadool and Ache, 1992;Boekhoff et al, 1994;Hatt and Ache, 1994;Fadool et al, 1995). Substantial evidence exists to suggest that two lobsters (Bayer et al, 1989;McClintock and Ache, 1989a,b).…”

“…This suggests that both pathways can coexist in a single ORN. In lobster ORNs this coexistence was established in single-cell recordings of the summation of depolarizing receptor potentials caused by odor-evoked InsPproduction and hyperpolarizing receptor potentials caused by odorevoked cAMP production (McClintock and Ache, 1989b;Michel et al, 1991;Fadool and Ache, 1992;Boekhoff et al, 1994;Hatt and Ache, 1994;Michel and Ache, 1994). The discovery that virtually all odorants can cause depolarizations in one lobster ORN but hyperpolarizations in another supports the hypothesis that this interaction is a mechanism of coincidence detection that allows a smaller number of ORNs to efficiently encode sophisticated information.…”

“…Odor responses are dependent on G proteins, odorants stimulate inositol phosphate production in outer dendritic membranes, inositol phosphates can activate several cation channels in the somatic and outer dendritic plasma membrane, and blockers of these channels also block odor responses Ache, 1992, 1994;Boekhoff et al, 1994;Hatt and Ache, 1994). The lack of sensitivity of odor responses to pertussis toxin preResubmitted manuscript…”

Olfactory regulation of mosquito–host interactions

“…While the precise olfactory second messengers have yet to be conclusively established in insects, there is considerable data to suggest that molecules such as cyclic AMP (cAMP) and most importantly, inositol 1,4,5-triphosphate (IP 3 ) play essential roles in transducing chemical signals from the environment into neuronal activity (Boekhoff et al, 1994;Reed, 1992). Insofar as insects are concerned, mutations in several IP 3 linked components including phospholipase C (norpA) show impaired olfactory function in D. melanogaster (Riesgo-Escovar et al, 1995) and odor induced IP3 signaling has been directly measured in the cockroach (Breer et al, 1990).…”

Visual arrestins in olfactory pathways of Drosophila and the malaria vector mosquito Anopheles gambiae

“…Olfactory transduction is mediated by G protein-coupled receptor (GPCR) second messenger pathways (1,2). Olfaction exhibits not only activation but also adaptation, whereby a progressively weaker response is generated to repeated or persistent stimuli.…”