Table 1.

Kinetic parameters of functional turnover for the recovery of ME (3.2 μM, 1 min)‐induced inhibitory effect after β‐FNA (300 and 800 nM, 30 min) administration

	β‐FNA 300 nM (n = 5)	β‐FNA 800 nM (n = 5)
ME effect (%)
Control	99.5 ± 0.3	96.2 ± 1.4
t 30 = 0 min	7.8 ± 2.6	7.8 ± 3.0
t 30 = 300 min	69.8 ± 9.6	73.3 ± 9.6
Functional turnover of ME effect
r′ (Emax · min−1)	2.00 ± 0.13	1.78 ± 0.32
k′ (min−1)	0.035 ± 0.007	0.024 ± 0.005
t ½′ (min)	22 ± 3	36 ± 8
E ss (%)	62.0 ± 7.9	77.0 ± 7.1
Functional turnover of μ receptor
r (R t · min−1)	0.25 ± 0.06*	0.52 ± 0.20*
k (min−1)	0.022 ± 0.009	0.018 ± 0.004
t ½ (min)	45 ± 9*	44 ± 9
R ss (%)	16 ± 3*	37 ± 15*

Values are expressed as mean ± SEM obtained by nonlinear regressions of n cells (see the Methods section). Parameters: r′ and k′ are the reappearance and disappearance rate constants of ME effect, t _½ ′ is the t _1/2 of ME effect, E _ss is the maximal recovery of ME effect at steady state, r and k are the reappearance and disappearance rate constants of the receptor, t _½ is the t _1/2 of the receptor and R _ss is the maximal recovery of the receptor at steady state.

^* P < 0.05, when compared with the corresponding parameter values for turnover of ME effect. No significant differences were found between the effects of the two concentrations of β‐FNA (300 and 800 nM).