TABLE 3

Peripheral inflammatory injury does not alter the potency (EC50) or efficacy (Emax) of DAMGO to stimulate binding of [35S]GTPγS in the rostral ventromedial medulla

Concentration-response curves were generated for DAMGO-induced stimulation of the binding of [35S]GTPγS to membranes containing the rostral ventromedial medulla of rats 4 h, 4 days, or 2 wk after intraplantar injection of saline or CFA in one hindpaw. Values are the mean ± S.E.M. of three to four independent experiments. Data are the percentage of change from basal values in the absence of DAMGO.


Intraplantar Treatment

DAMGO
Emax
EC50
% nM
stimulation
4 h
    Saline 41.4 ± 8.6 91.0 ± 20.1
    CFA 37.6 ± 7.7 141.7 ± 25.1
4 Days
    Saline 40.5 ± 7.2 130.7 ± 54.0
    CFA 48.1 ± 4.6 126.7 ± 36.1
2 Weeks
    Saline 33.5 ± 5.1 125.3 ± 24.0
    CFA
35.9 ± 7.6
128.3 ± 35.7