Figure 2: Number of nicotine (NIC)- and nicotine pyrrolidine methiodide (NIC-PM)-induced c-Fos activated cells colocalized with tyrosine hydroxylase (TH)–immunoreactive cells in locus coeruleus (LC). Number of c-Fos activated cells significantly greater for NIC and NIC-PM, compared to physiological saline (PS) control (*P<0.001). Number of cells co-expressing c-Fos and TH significantly greater for NIC and NIC-PM, compared to PS control (**P<0.001). Data expressed as mean ± standard deviation.