Parameters describing effects of nicotine exposure on nAChR numbers and function
| Cell type and nAChR subtype | Measure | τ | Parameter | EC50/IC50 |
|---|---|---|---|---|
| hr | % increase/(decrease) | μM | ||
| TE671/RD | intracellular Carb-sensitive I-Bgt binding | 0.69 /26 | 85 /340 | |
| (alpha-1beta-1 gamma delta) | intracellular Carb-insensitive I-Bgt binding | 0.69 /26 | 11 /46 | |
| Cell surface Carb-sensitive I-Bgt binding | 0.035 /6.9/14 | (50) /50/140 | ||
| Cell surface Carb-insensitive I-Bgt binding | 0.035 /0.34/23 | (60) /60/50 | ||
| Membrane [3H]ACh binding | 0.36 /26 | 60 /360 | ||
| 140 /290 | 1.3 /800 | |||
| Membrane Carb-sensitive I-Bgt binding | 0.36 /26 | 40 /340 | ||
| 88 /440 | 1.3 /800 | |||
| Membrane Carb-insensitive I-Bgt binding | 0.36 /26 | 0 /38 | ||
| 49 | 1.6 | |||
| Function | 0.016 /0.32 | (45) /(55) | ||
| (93) | (0.79) | |||
| SH-SY5Y | Membrane [3H]ACh binding | 23 | 580 | |
| (alpha-3 beta-4) | 270 /770 | 6 /480 | ||
| Function | 0.0027 /0.12 | (56) /(26) | ||
| (92) | (5.2) | |||
| SH-SY5Y | Intracellular I-Bgt binding | 0.14 /36 | 23 /240 | |
| (alpha-7) | Cell surface I-Bgt binding | 1.1 /90 | (34) /100 | |
| Membrane I-Bgt binding | 180 | 810 | ||
| BC3H-1 | Membrane I-Bgt binding | 6.9 | 80 | |
| (alpha-1 beta-1 gamma delta) | 93 | 200 |
The indicated cell types expressing specified nAChR subtypes were subjected to nicotine treatments and measures of radioligand binding densities or functional activity as described in “Experimental Procedures.” Summarized here (to two significant digits) are time constants for nicotine effects (hr), the percentage change in nAChR numbers or function reflecting these effects (decreases are enclosed in parentheses) and the EC50 (or IC50 in parentheses) values for those effects (μM). In cases where effects were bi- or tri-phasic, parameters in each column are separated in order by “slashes.” See appropriate figure legends and text for details.