[D-Thr2, Thz5]-enkephalinamide administered orally or subcutaneously inhibited the tail-flick response to heat stimuli in mice. On a molar basis, this peptide was found to be 1.5-1.7 times more potent than morphine by oral administration.
Bibliographical noteFunding Information:
This work was supported in part by grants from NIDA No . DA-01314 (to L-F . T,), DA-00564 (to H .H .L .), NIMH MH-30245 and Hormone Research Foundation (to C .H .L .) .