Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Cyclic nucleotide and IP3 gated ion channels in hermit crab olfactory receptor neurons
Student Author(s): Christy, Ilia
Faculty Advisor(s): Thompson, Stuart
Pages: 29
Location: Final Papers Biology 175H
Date: June 1996
Abstract: Cyclic 3',5'-guanosine monophosphate (cGMP) and 1,4,5-inositol trisphosphate (IP3) both act as secondary messengers in odor transduction, activating ion channels in Pagurus samuelis olfactory receptor neurons. Two different cGMP-gated ion channels were observed in inside-out patches in symmetrical Na+ solutions: one with a conductance of 22 pS, and the other with a more varied conductance of approximately 86 pS. Unlike cGMP-gated channels in vertebrate olfactory receptors which are blocked by divalent cations, these cGMP channels were not blocked by 60 mM Mg++. They were however completely blocked by the addition of Ca++ to the inner face of the patch. An IPa3-gated ion channel with a conductance of 13 pS was observed that wad also not blocked by Mg++. There was also suggestion of two additional IP3 channels with larger conductances. This study is the first to demonstrate the presence of cGMP- and IP3-gated ion channels in Pagurus olfactory receptor neurons. This dual signal transduction pathway, mediated by cGMP and IP3, may allow for the integration of a broader range of information representing a blend of odors.