Male Swiss mice weighing 25 to 35 g were used. Peptoids were injected intraperitoneally 10 min before ammonium injection. Ammonium acetate (14 mmol/kg) was also injected intraperitoneally. The concentrations of the solutions were adjusted to reach the desired dose by injecting 3 μl per gram of body weight. The number of surviving mice was counted 24 h after ammonium injection. All animals surviving at this time remained alive for several weeks until they were sacrificed.