The role of arachidonic acid metabolism in somatostatin and substance P effects on inward rectifier K conductance in rat brain neurons.
Somatostatin enhances an inward rectifier K conductance in cultured locus coeruleus neurons, while substance P reduces an inward rectifier K conductance in cultured nucleus basalis and locus coeruleus neurons. The role of arachidonic acid metabolites in these responses was studied. The somatostatin-induced response was reduced by phospholipase A2 inhibitors, non-specific lipoxygenase inhibitors and specific 5-lipoxygenase inhibitors. A cyclooxygenase inhibitor and a 12-lipoxygenase inhibitor had no effect. 5(S)-HPETE occasionally increased the K conductance, but failed to occlude the somatostatin response. The substance P response was suppressed by a 5-lipoxygenase inhibitor but not by a 12-lipoxygenase inhibitor. These results suggest that the 5-lipoxygenase pathway is not a specific messenger of either one of these responses, but that it plays a more general role in maintaining or enhancing the effectiveness of both somatostatin and substance P responses.
Koyano
K
K
Department of Anatomy and Cell Biology, University of Illinois College of Medicine at Chicago 60612.
Grigg
J J
JJ
Velimirovic
B M
BM
Nakajima
S
S
Nakajima
Y
Y
D000818:Animals; D016718:Arachidonic Acid / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000502:physiology*; D004553:Electric Conductivity; D015289:Leukotrienes / Q000494:pharmacology; D008125:Locus Coeruleus / Q000166:cytology / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D011188:Potassium / Q000502:physiology*; D016548:Prosencephalon / Q000166:cytology / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000494:pharmacology*; D013373:Substance P / Q000494:pharmacology*
D015289:Leukotrienes; D016718:Arachidonic Acid; D013373:Substance P; D013004:Somatostatin; C025348:arachidonic acid 5-hydroperoxide; D011188:Potassium