alpha7 Nicotinic acetylcholine receptor stimulation inhibits lipopolysaccharide-induced interleukin-18 and -12 production in monocytes.

Nicotine inhibited interleukin (IL)-18 and -12 production in lipopolysaccharide (LPS)-stimulated monocytes, and the action of nicotine was antagonized by a non-selective and a selective alpha7 nicotinic acetylcholine receptor (alpha7-nAChR) antagonist, suggesting that the stimulation of alpha7-nAChR may be involved in the action of nicotine. Nicotine is reported to induce prostaglandin E(2) (PGE(2)) production in monocytes through the up-regulation of cyclooxygenase (COX)-2 expression. PGE(2) is known to increase cAMP levels and to activate protein kinase A (PKA). COX-2 and PKA inhibitors prevented the action of nicotine, indicating that the mechanism of action of nicotine may be via endogenous PGE(2) production.