Table 2.

Mecamylamine-precipitated nicotine withdrawal in wild-type and μ-opioid receptor knock-out mice

Wild-type miceKnock-out mice
SalineNicotineSalineNicotine
Locomotor activity6.45 ± 0.514.92 ± 0.506.04 ± 0.305.08 ± 0.53
Body tremor4.45 ± 0.395.12 ± 0.283.50 ± 0.355.08 ± 0.24
Genital licks1.05 ± 0.221.92 ± 0.321.04 ± 0.231.08 ± 0.20
Ptosis0.35 ± 0.221.52 ± 0.320.96 ± 0.271.04 ± 0.31
Wet dog shakes0.95 ± 0.311.84 ± 0.440.79 ± 0.191.69 ± 0.36
Teeth chattering0.40 ± 0.132.00 ± 0.320.46 ± 0.160.78 ± 0.28
Paw tremor3.35 ± 0.696.60 ± 1.022.42 ± 0.594.48 ± 0.80
Scratches1.25 ± 0.433.4 ± 0.931.70 ± 0.621.52 ± 0.43
Piloerection0.00 ± 0.000.76 ± 0.280.12 ± 0.070.56 ± 0.29
GWS11.80 ± 0.7020.78 ± 1.3511.52 ± 0.7115.87 ± 0.89
  • Data are expressed as mean ± SEM. Two-way ANOVA revealed a significant effect of nicotine treatment for locomotor activity, body tremor, wet dog shakes, teeth chattering, paw tremor, piloerection, global withdrawal scores (GWS) (p < 0.01), and ptosis (p < 0.05).