Nicotine Inhibits Clostridium difficile Toxin A-Induced Colitis but Not Ileitis in Rats

Figure 7

Effect of nicotine pretreatment on toxin A-induced release of endogenous substance P (SP) in the rat colon. (a) Confocal image of neurokinin-1 (NK-1) receptor distribution on a myenteric plexus neuronal ganglionic cell body in a control rat treated with vehicle. The NK-1 receptor is localized on the plasma membrane. (b) Confocal image of neurokinin-1 (NK-1) receptor distribution on a myenteric plexus neuronal ganglionic cell body in a control rat treated with nicotine (0.2 μg). Nicotine alone has no effect on SP-induced NK-1 receptor endocytosis. (c) Confocal image of neurokinin-1 (NK-1) receptor distribution on a myenteric plexus neuronal ganglionic cell body in a rat treated with toxin A (5 μg). Toxin A causes endogenous SP release seen here as NK-1 receptor endocytosis. (d) Confocal image of neurokinin-1 (NK-1) receptor distribution on a myenteric plexus neuronal ganglionic cell body in a rat pretreated with nicotine (0.2 μg) before toxin A (5 μg). Nicotine prevented toxin A-induced SP release in colon. Line bar = 100 μm. (e) Quantitation of the effects of toxin A and nicotine on SP release in the rat colon. versus control; versus control; versus toxin A; .

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