Tolerance development to buprenorphine in prenatally buprenorphine-exposed male rats. (A) The latency and AUC of rats after receiving first injection of buprenorphine (B) The latency and AUC of rats after receiving 4th injection of buprenorphine. (C) Rate of tolerance development to buprenorphine in buprenorphine or saline prenatally exposed rats. There was no difference in tolerance development to buprenorphine (F(1, 31) = 0.073, p = 0.789) between the buprenorphine and saline prenatally exposed groups. All data are expressed as mean ± S.E.M, (N = 4 per group).