4.3 Article

Identification of second messenger mediating signal transduction in the olfactory receptor cell

Journal

JOURNAL OF GENERAL PHYSIOLOGY
Volume 122, Issue 5, Pages 557-567

Publisher

ROCKEFELLER UNIV PRESS
DOI: 10.1085/jgp.200308911

Keywords

olfactory receptor cell; signal ttransduction; second messenger; cAMP; caged compound

Categories

Ask authors/readers for more resources

One of the biggest controversial issues in the research of olfaction has been the mechanism Underlying response generation to odorants that have been shown to fail to produce cAMP when tested by biochemical assays with olfactory ciliary preparations. Such observations are actually the original source proposing a possibility for the presence of multiple and parallel transduction pathways. In this study the activity of transduction channels in the olfactory cilia was recorded in cells that retained their abilities of responding to odorants that have been reported to produce InsP(3) (instead of producing cAMP, and therefore tentatively termed InsP(3) odorants). At the same time, the cytoplasmic cNMP concentration ([cNMP](i)) was manipulated through the photolysis of caged compounds to examine their real-time interactions with odorant responses. Properties of responses induced by both InsP,, odorants and cytoplasmic cNMP resembled each other in their unique characteristics. Reversal potentials of currents were 2 mV for InsP, odorant responses and 3 mV for responses induced by cNMP. Current and voltage (I-V) relations showed slight outward rectification. Both responses showed voltage-dependent adaptation when examined with double pulse protocols. When brief pulses of the lnsP(3) odorant and cytoplasmic cNMP were applied alternatively, responses expressed cross-adaptation with each other. Furthermore, both responses were additive in a manner as predicted quantitatively by the theory that signal transduction is mediated by the increase in cytoplasmic cAMP. With lnSP(3) odorants, actually, remarkable responses Could be detected in a small fraction of cells (similar to2%), explaining the observation for a small production of cAMP in ciliary preparations obtained from the entire epithelium. The data will provide evidence showing that olfactory response generation and adaptation are regulated by a uniform mechanism for a wide variety of odorants.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.3
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available