Fig. 6. Antinociceptive effects following cold water swim (CWS) stress after intrathecal morphine treatment. After 48 h (C ) but not after 6 h (A ), PPT elevations were significantly lower in intrathecal morphine–treated compared with intrathecal saline–treated rats at 5 min after CWS (means ± SD; n = 7; *P < 0.05, analysis of variance). The area under the curve was significantly decreased in intrathecal morphine–treated (M) rats compared with intrathecal saline–treated (C) rats at 48 h (D ) but not at 6 h (B ) (means ± SD; n = 7; *P < 0.05, analysis of variance).