Figure 5.

Pharmacologic antagonism of muscarinic or nicotinic acetylcholine receptors has no effect on diazinon-induced cytokine expression in THP1 cells. Differentiated THP1 cells were pretreated for 1 hour with 100 μM atropine (Atr) to block muscarinic receptors or 100 μM mecamylamine (Meca) to block nicotinic receptors before the addition of 100 μM DZN or vehicle (veh; 0.1% DMSO) for 24 hours. (A and C) Cellular levels of TNF-α (A) and IL-1β (C) mRNA were quantified by real-time PCR and normalized to 18S rRNA. (B and D) Levels of TNF-α (B) and IL-1β (D) protein in conditioned media were quantified by ELISA. The effect of DZN on mRNA and protein expression was expressed as a fold change over expression in vehicle control cells not exposed to atropine or mecamylamine (white bar) in each experiment. Data are presented as the mean ± SEM (each exposure was performed in triplicate wells; n = 4–5 separate experiments for each exposure). *Significantly different from vehicle control (white bar) at P ≤ 0.05.