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Objective To define the effect and mechanism of hyperkalemic solution on atrial natriuretic peptide (ANP) secretion in rabbits. Methods Eighteen rabbits were selected and the chest was opened under anes-thetization to remove the heart. The left atrium was isolated and fixed in the atrial perfusion system with proper electric stimulation for beating. The following experiments were carried out on beating rabbit atria: ①The atrium was perfused for 60 min to stabilize parameters of ANP secretion and atrial dynamics. The control period (12 min as an experimental cycle) was followed by an infusion of hyperkalemic solution (K+ concentration of hyperkalemic solution was 5.64 mmol/L and the osmolarity of hyperkalemic solution was unchanged) for three cycles, then normal K+ cancentration was recovered for two cycles;②The control period was followed by an infusion of L type Ca2+ channel blocker nifedipine (1.0 μmol/L) for three cycles;③L type Ca2+ channel inhibitor nifedipine (1.0 μmol/L) was infused for 36 rain prior (three cycles) to infusion of hyperkalemic solution. Atrial stroke volume was determined and the ANP secretion was measured by radioimmtmoaasay. Results (1)Hyperkalemic solution increased atrial ANP secretion (P<0.01) and reduced the atrial stroke volume,hut the difference was not statistically significant as compared with that of the control cycle(P>0.05). The recovery trend was to the normal level of ANP secretion and atrial stroke volume was to become normal gradually when solution level recovered to normal ,which was not significantly different from that of the control cycle (P>0.05) ;②Nifedipine (1.0 μmol/L) also increased the atrial ANP secretion (P<0.01 or P <0.05) while decreasing atrial stroke volume (P<0.01 or P < 0.05 ) ; ③Nifodipine (1.0μmol/L) completely blocked the effect of hyperkalemic solution so to increase the ANP secretion (P <0.01 ). Conclusion Hyperkalemic solution significantly increases atrial ANP secretion via extracellular high K+ competitive inhibition of extracellular Ca2+ inflow in beating rabbit atria.

6.One case of pleomorphic adenoma of the larynx.

Li-yan PENG ; Hong-tao ZHEN ; Yong-hua CUI

Chinese Journal of Otorhinolaryngology Head and Neck Surgery 2007;42(9):691-691

7.Preliminary establishment of dry eye model in non-obese diabetic mice

Hong Cui

International Eye Science 2019;19(8):1293-1296

AIM:To determine the pathological changes in ocular surfaces dry eye excessive evaporation non-obese diabetic(NOD)mice model and to preliminarily explore the feasibility of diabetic dry eye model.

METHODS: In this study, 40 females NOD mice were selected. The experimental group consisted of NOD mice that were diagnosed with diabetes while the normal control group consisted of those NOD mice without spontaneous diabetes. Hypodermic injection of Scopolamine hydrobromide(0.5mg/0.2mL)was administered under 40% humidity to the experimental group and placed in a controlled drying box for 12h a day. This was to achieve a dry eye model. Testing indicators on the 1, 7, 10 and 14d after modeling, phenol red thread test was used to measure tear secretion and the eye sections were stained with periodic acid-Schiff(PAS)to examine the morphology and number of conjunctival goblet cells. On the 10d after modeling, the changes in the corneal epithelium were visualized after staining with hematoxylin.

RESULTS:For the NOD mice of the experimental group, the tear secretion was gradually decreased with timing, while there were no obvious changes in the normal control group. The volume of the conjunctival goblet cells of the experimental group became larger, and on the 1d after the molding, the experimental group had decreased density of the goblet cells when compared with the normal control group(P=0.008). From the 7d after the molding, as the time was prolonged, the density of the goblet cells was gradually decreased and the differences between the two group at same time point were significant(all P<0.001). Besides, it was required to observe the corneal epithelium of the two groups on the 10d. The result shows that the corneal epithelium became thinned, some epithelial cells were denatured, and stromal cells became edema.

CONCLUSION: Dry eye model of NOD mice was preliminary established, and the changes of ocular surface were similar to those of dry eye in the clinic.