Medical College of Wisconsin
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Products of heme-catalyzed transformation of the arachidonate derivative 12-HPETE open S-type K+ channels in Aplysia. Neuron 1989 Oct;3(4):497-505

Date

10/01/1989

Pubmed ID

2642008

DOI

10.1016/0896-6273(89)90208-0

Scopus ID

2-s2.0-0024745316   59 Citations

Abstract

In Aplysia mechanosensory neurons, the neuropeptide FMRFamide increases the opening of the background S-K+ channel. This action is mediated by activation of arachidonic acid metabolism. Arachidonic acid in Aplysia nervous tissue is transformed through the 12-lipoxygenase pathway to 12-HPETE, which undergoes further metabolism. In intact sensory cells, 12-HPETE simulates the FMRFamide response, raising the question of whether 12-HPETE is the messenger molecule ultimately acting on the S-K+ channel. Here we show that in cell-free (inside-out) patches from sensory cells, 12-HPETE fails to modulate the S-K+ channel, but in the presence of hematin (which catalyzes 12-HPETE metabolism), it triggers sharp increases in the channel opening probability. We also found that SKF-525A, an inhibitor of the cytochrome P450, reduces the response to FMRFamide, arachidonic acid, and 12-HPETE in intact cells. We conclude that a heme-catalyzed transformation of 12-HPETE is necessary and sufficient to promote the opening of the S-K+ channel and a heme-containing enzyme such as cytochrome P450 might play this key role.

Author List

Belardetti F, Campbell WB, Falck JR, Demontis G, Rosolowsky M

Author

William B. Campbell PhD Chair, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Aplysia
Arachidonic Acids
Cell-Free System
FMRFamide
Heme
Hemin
Leukotrienes
Neuropeptides
Potassium Channels
Pyridines
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