BPC 157 antagonized the general anaesthetic potency of thiopental and reduced prolongation of anaesthesia induced by l-NAME/thiopental combination

We hypothesized that certain effects of the general anaesthetic thiopental are dependent on NO-related mechanisms, which were consequently counteracted by stable gastric pentadecapeptide BPC 157. (1) All rats intraperitoneally received thiopental (20, 30, 40, and 50 mg/kg) while medication BPC 157 (10 μg/kg, 10 ng/kg, and 10 pg/kg) was given intraperitoneally at 5 min before thiopental. (2) To determine NO-related mechanisms, all rats received intraperitoneally thiopental 40 mg/kg while BPC 157 (10 μg/kg), l-NAME (10 mg/kg) and l-arginine (30 mg/kg) were applied alone and/or combined. BPC 157 was given at 25 min before thiopental while l-NAME, l-arginine, alone and/or combined, were applied at 20 min before thiopental. (1) BPC 157 own effect on thiopental anaesthesia: BPC 157 (10 ng/kg and 10 μg/kg) caused a significant antagonism of general anaesthesia produced by thiopental with a parallel shift of the dose–response curve to the right. (2) l-NAME-l-arginine-BPC 157 interrelations: l -NAME: Thiopental-induced anaesthesia duration was tripled. l-arginine: Usual thiopental anaesthesia time was not influenced. Active only when given with l-NAME or BPC 157: potentiating effects of l-NAME were lessened, not abolished; shortening effect of BPC 157: abolished. BPC 157 and l -NAME: Potentiating effects of l-NAME were abolished. BPC 157 and l -NAME and l-arginine: BPC 157 +l-NAME +l-arginine rats exhibited values close to those in BPC 157 rats. Thiopental general anaesthesia is simultaneously manipulated in both ways with NO system activity modulation, l-NAME (prolongation) and BPC 157 (shortening/counteraction) and l-arginine (interference with l-NAME and BPC 157).