Desensitization to LPS after ethanol involves the effect of endotoxin on voltage-dependent calcium channels.
Hepatic macrophages are sensitized to alcohol in 24 h due to increases in the endotoxin receptor, CD14; however, desensitization to lipopolysaccharide (LPS), which occurred earlier, could not be explained by changes in CD14. Therefore, the purpose of this work was to attempt to understand factors responsible for ethanol-induced desensitization to LPS in hepatic macrophages. Rats were given ethanol (5 g/kg body wt) intragastrically, and hepatic macrophages were isolated 2 h later. After addition of endotoxin, intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured using fura 2 and tumor necrosis factor (TNF)-alpha was measured by ELISA. Ethanol given 2 h before injection of LPS totally prevented liver injury and blunted LPS-induced increases in [Ca(2+)](i) and TNF-alpha in hepatic macrophages. Furthermore, the protein kinase C (PKC) agonist phorbol 12-myristate 13-acetate and acute ethanol treatment both activated PKC and largely prevented the influx of [Ca(2+)](i) caused by LPS. Sterilization of the gut with antibiotics completely blocked all effects of ethanol on [Ca(2+)](i) and TNF-alpha release. Thus ethanol-induced desensitization of hepatic macrophages correlates with gut-derived endotoxin after ethanol and involves the effect of PKC on voltage-dependent Ca(2+) channels.
Enomoto
N
N
Laboratory of Hepatobiology and Toxicology, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7365, USA.
Yamashina
S
S
Goto
M
M
Schemmer
P
P
Thurman
R G
RG
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology*; D002492:Central Nervous System Depressants / Q000097:blood / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D008070:Lipopolysaccharides / Q000097:blood / Q000494:pharmacology*; D008099:Liver / Q000737:chemistry / Q000166:cytology / Q000201:enzymology; D008264:Macrophages / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology; D052998:Microcystins; D010456:Peptides, Cyclic / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016019:Survival Analysis; D000637:Transaminases / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015220:Calcium Channels; D002492:Central Nervous System Depressants; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D052998:Microcystins; D010456:Peptides, Cyclic; D014409:Tumor Necrosis Factor-alpha; D000431:Ethanol; C078588:microcystin; D000637:Transaminases; D011493:Protein Kinase C; D002118:Calcium