Altered vascular response to acetylcholine in conditions of endothelial damage in the isolated perfused rat stomach

Analysis of the mechanisms of rabbit’s brainstem hemorrhage complicated with irritable changes in the alvine mucous membrane

AIM: To explore the dynamic changes in the pressure of the lateral ventricle during acute brainstem hemorrhage and the changes of neural discharge of vagus nerve under the load of intracranial hypertension, so as to analyze their effects on the congestive degree of intestinal mucous membrane and the morphologic changes of intestinal mucous membrane.

METHODS: An operation was made to open the skull to obtain an acute brainstem hemorrhage animal model. Microcirculatory microscope photography device and video recording system were used to determine the changes continuously in the caliber of jejunal mesenteric artery during brainstem hemorrhage and the changes with time in the congestion of jejunal mucosal villi. We used HE stain morphology to analyze the changes of duodenal mucosal villi. A recording electrode was used to calculate and measure the electric discharge activities of cervical vagus nerve.

RESULTS: (1) We observed that the pressure of lateral cerebral ventricle increased transiently during acute brainstem hemorrhage; (2) The caliber of the jejunal mesenteric artery increased during brainstem hemorrhage. Analysis of red color coordinate values indicated transient increase in the congestion of jejunal mucous membrane during acute brainstem hemorrhage; (3) Through the analysis of the pathologic slice, we found enlarged blood vessels, stagnant blood, and transudatory red blood cells in the duodenal submucous layer; (4) Electric discharge of vagus nerve increased and sporadic hemorrhage spots occurred in duodenal mucous and submucous layer, when the lateral ventricle was under pressure.

CONCLUSION: Brainstem hemorrhage could cause intracranial hypertension, which would increase the neural discharge of vagus nerve and cause the transient congestion of jejunal mucous membrane. It could cause hyperemia and diffused hemorrhage in the duodenal submucous layer 48 h after brainstem hemorrhage.

Effect of Dansen on gastric mucosal Na+-K+-ATPase activity and gastric transmucosal potential difference during severe intraperitoneal infection in rats

AIM: To investigate the effect of Dansen on gastric mucosal Na⁺-K⁺-ATPase activity and gastric transmucosal potential difference during severe intraperitoneal infection in rats.

METHODS: The intraperitoneal infection rat model was established by cecal ligation and puncture (CLP). Assay of Na⁺-K⁺-ATPase activity in gastric mucosal tissue was conducted by biochemical method. The electric-physiological recorder was used to measure gastric mucosal potential difference.

RESULTS: The activity of Na⁺-K⁺-ATPase was markedly decreased in infected group at 3h after perforation, compared with the control group (P = 0.0 271 < 0.05). There was a minimum of Na⁺-K⁺-ATPase activity at 12h post-perforation in infected group (P = 0.0 062 < 0.01), only about 48.5% matched to the control group. Gastric transmucosal potential difference (GTPD) of infected group decreased significantly as compared with the control group (P = 0.0 253 < 0.05) at 6h after perforation, and rapidly dropped to the lowest at 12 h post-perforation (P = 0.0 025 < 0.01). At 12 h and 24 h after perforation, GTPD was lower in infected group than that in the control group (P = 0.0 293 < 0.05).

CONCLUSION: The reduce of Na⁺-K⁺-ATPase activity may play an important role in gastric mucosal barrier damage following severe abdominal infection induced by CLP, and the application of Dansen in earlier period can prevent the occurrence of stress ulcer.

Gastroduodenal mucosal defense

The gastroduodenal mucosa is a model system of defense with several structural levels and biologic strategies that are closely interrelated with each other to cope with the harmful ingredients of ingested food and the potentially deleterious effects of gastric acid and pepsin. Experimental and clinical research carried out during the review period added to the understanding of each component of the multiple mechanisms of gastroduodenal mucosal protection. In the first place, mucosal integrity is defended by the mucus gel barrier, the epithelial cell barrier, and the immune barrier. The properties of these barriers are maintained by adequate regulation of mucus production, bicarbonate secretion, mucosal microcirculation, and motor activity. These regulatory systems are alarmed by nociceptive neurons and the mucosal immune system which includes chemokine-secreting epithelial cells. The ultimate defense system is rapid repair of the injured mucosa under the control of several growth factors. Progressing insight into the network of mucosal defense not only will improve existing therapies of inflammation and ulceration but also will provide new leads for the management of functional diseases in the gastroduodenal region.