A lipoxygenase pathway of arachidonic acid metabolism mediates FMRFamide activation of a potassium current in an identified neuron of Helisoma.
The neuropeptide FMRFamide causes a presynaptic inhibition of neurotransmitter release from neuron B5 of Helisoma. In this study we demonstrate that one of FMRFamide's actions is to activate an outwardly rectifying potassium current. Arachidonic acid also activates an outward current in B5. The phospholipase A2 inhibitor, 4-bromophenacylbromide (BPB), and nordihydroguaiaretic acid (NDGA), an inhibitor of arachidonic acid metabolism, but not indomethacin, block FMRFamide's activation of the potassium current. Taken together these data demonstrate that one of FMRFamide's presynaptic actions is to activate a potassium current through a lipoxygenase pathway of arachidonic acid metabolism.
Bahls
F H
FH
Department of Zoology and Genetics, Science II, Iowa State University, Ames 50011.
Richmond
J E
JE
Smith
W L
WL
Haydon
P G
PG
D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D019835:FMRFamide; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007447:Invertebrate Hormones / Q000494:pharmacology*; D008084:Lipoxygenase / Q000378:metabolism*; D009637:Masoprocol / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008974:Mollusca; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology*; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D011188:Potassium / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*
D000098:Acetophenones; D001095:Arachidonic Acids; D007447:Invertebrate Hormones; D009479:Neuropeptides; D015221:Potassium Channels; D019835:FMRFamide; D009637:Masoprocol; D008084:Lipoxygenase; D010741:Phospholipases A; D054467:Phospholipases A2; C006821:4-bromophenacyl bromide; D011188:Potassium; D007213:Indomethacin