“…(1976) found naloxone ineffective, whereas King, Hughey, Massareno, Codd & Byrne (1977) and Berntson & Walker (1977) reported a decrease in reaction time induced by naloxone. However, naloxone does not affect other nociceptive reactions such as escape from foot-shock in trained rats (Goldstein, Pryor, Otis & Larsen, 1976), escape from tail-pinch (Berntson & Walker, 1977), writhing in mice (Elliott, Spieghler & Navarro, 1976) or pain rating in humans (Sobky, Dostrovsky & Wall, 1976;Grevert & Goldstein, 1977a).…”