Table 2. AChRs exhibit three different half-lives, depending on the state of innervation.

	compartment size%	rate constant(d−1)	half-life(d)	mean lifetime (d)
innervatedfast compartment	13±2	0.630±0.191	1.1±0.3	1.6±0.5
innervatedslow compartment	87±2	0.053±0.002	13.1±0.4	18.9±0.6
acutely denervatedfast compartment	5±2	0.630±0.417	1.1±0.7	1.6±1.1
acutely denervatedslow compartment	95±2	0.086±0.002	8.1±0.2	11.6±0.2
long-term denervatedfast compartment	51±4	0.630±0.070	1.1±0.1	1.6±0.1
long-term denervatedslow compartment	49±4	0.086±0.007	8.1±0.6	11.6±0.6

TA muscles of anaesthetized mice were injected with ¹²⁵I-BGT on day zero and then ¹²⁵I emission from injected hindlimbs was measured over 25 days. Regressions from data sets normalized to day 2 after pulse labeling were calculated using two-exponential terms and t_1/2 values of 1.1 days (fast compartment), 8.1 days (intermediate compartment) and 13.1 days (slow compartment). The table shows compartment sizes, rate constants, half-lives, and mean receptor lifetimes, all ± SD (n-values: control n = 10, acutely denervated n = 5, long-term denervated n = 4).