Morphometric study of neuromuscular junction in rabbits subjected to shock by superior mesenteric artery occlusion.

The purpose of this study was to describe changes in the neuromuscular junction of rabbit sartorius muscle after shock by superior mesenteric artery occlusion in 18 rabbits. The results revealed that the numeric and volume densities of the acetylcholine (Ach) vesicles of the sartorius neuromuscular junction were decreased during shock when compared by electron microscopy with normal subjects (p less than .001). We also discovered that the release of lysosomes from hepatic cells, erythrocyte acetylcholinesterase (AchE) activity, and hepatic ATP values decreased during shock. Both scopolamine (0.023 mg/kg) and verapamil (0.74 mg/kg) blocked the release of Ach vesicles and lysosomes, and increased hepatic ATP values. Scopolamine also increased AchE activity. This study shows that the parasympathetic activation plays an important role in mesenteric artery occlusion shock.