Kounenis G, Koutsoviti-Papadopoulou M, Elezoglou V
Department of Pharmacology, Faculty of Veterinary Medicine, Aristotelian University, Thessaloniki, Greece.
Pharmacol Res. 1994 Feb-Mar;29(2):155-61. doi: 10.1016/1043-6618(94)80039-1.
The influence of varying concentrations of the H2-receptor antagonists nizatidine and ranitidine on the acetylcholine- and carbachol-induced contractures on the toad rectus abdominis muscle, as well as the possible interaction between the above H2-receptor antagonists and D-tubocurarine were studied. Nizatidine and ranitidine at a concentration of 3.2 x 10(-4) mol l-1 augmented, and at 3.2 x 10(-3) mol l-1 inhibited, the acetylcholine-induced contractures on the toad rectus abdominis muscle, while at concentrations from 3.2 x 10(-4) to 3.2 x 10(-3) mol l-1 they inhibited the carbachol-induced contractures, in a concentration-dependent manner. In addition, nizatidine and ranitidine at a concentration of 3.2 x 10(-4) mol l-1 reversed the D-tubocurarine blocking activity on the acetylcholine-induced contractures, but at a concentration of 3.2 x 10(-3) mol l-1 they augmented it. These findings provide evidence that the above H2-receptor antagonists produce either cholinesterase inhibition or neuromuscular blockade, depending on their concentration. Thus, the D-tubocurarine neuromuscular blocking activity is potentiated at high concentrations of nizatidine and ranitidine, while it is reversed at lower ones.
研究了不同浓度的H2受体拮抗剂尼扎替丁和雷尼替丁对蟾蜍腹直肌乙酰胆碱和卡巴胆碱诱导的挛缩的影响，以及上述H2受体拮抗剂与筒箭毒碱之间可能的相互作用。浓度为3.2×10⁻⁴mol/L的尼扎替丁和雷尼替丁增强了蟾蜍腹直肌乙酰胆碱诱导的挛缩，而浓度为3.2×10⁻³mol/L时则抑制了该挛缩；在3.2×10⁻⁴至3.2×10⁻³mol/L的浓度范围内，它们以浓度依赖性方式抑制卡巴胆碱诱导的挛缩。此外，浓度为3.2×10⁻⁴mol/L的尼扎替丁和雷尼替丁可逆转筒箭毒碱对乙酰胆碱诱导挛缩的阻断活性，但在浓度为3.2×10⁻³mol/L时则增强了该活性。这些发现提供了证据，表明上述H2受体拮抗剂根据其浓度产生胆碱酯酶抑制或神经肌肉阻滞作用。因此，在高浓度的尼扎替丁和雷尼替丁作用下，筒箭毒碱的神经肌肉阻断活性增强，而在低浓度下则被逆转。
