[Changes in electrical potentials of gastric mucosa during various types of experimental hypoxia]. / Zmiany potencjalów elektrycznych blony sluzowej zoladka w warunkach doswiadczalnej hipoksji wywolanej róznymi czynnikami.

In experiments performed on anaesthetized male and female Wistar rats the effects of different types of hypoxia on the electrical potential difference (PD) between the inner and the outer sides of the gastric wall were examined. The PD was determined by mean of the Digital Multimeter VC-10T, Unitra, and the calomel electrodes connected with the KCl-agar bridges. There were four series of experiments carried out in which hypoxia was produced by: I--low atmospheric pressure (hypobaric hypoxia) corresponding with the altitudes of 2500, 5500, 8500 and 10,500 m above sea level, II--1 min. nitrogen breathing (anoxic anoxia), III--bleeding ca. 1% of the body weight (anemic hypoxia), IV--the gastric vessels ligation (ischemic hypoxia). There were also performed the adequate control experiments of each series. In all types of hypoxia (I--IV) a decrease in the PD was observed. The value and rate of this decrease were dependent on the type, grade, duration and rate of hypoxia. In the conditions of the hypobaric hypoxia simulated altitude 10,500 m only evoked the statistically significant PD drops, by 31%. The nitrogen breathing caused the PD decrease by 23% and the anemic hypoxia by 18%. In the ischemic hypoxia the total disappearance of the potential difference (PD = 0 mV) was observed. In the control experiments small non significant fluctuations, not exceeding 4%, occurred only. The decrease in the PD of the gastric wall observed during hypoxia could be explained by the changes in the membrane transport e.g. the back-diffusion of Na+, Cl-, and H+ ions.

Interference of psychotropic drugs with the injuring action of ethanol on gastric mucosal barrier.

The aim of this study was to establish whether some psychotropic drugs, applied to patients under influence of alcohol, may potentiate its damaging action on gastric mucosal barrier. A sensitive index of such damage is a decline of the potential difference (PD) across the stomach wall. The experiments were carried out on Wistar rats of either sex, anesthetized with urethane-chloralose. The PD values were assayed with an apolarization method. The investigated solutions were administered intragastrically by gavage. Ethanol at a concentration of 40% v/v depressed PD by 39%. The investigated psychotropic drugs did not change PD by themselves but given in combination with ethanol caused significant decline of PD: diazepam (0.4 mg/kg) by 58%, chlorpromazine (6.7 mg/kg) by 59%, imipramine (2 mg/kg) by 48%, amitriptyline (4 mg/kg) by 49%, phenytoin (4 mg/kg) by 53%, pyridinol (0.3 mg/kg) by 58%. Intragastric administration of water did not change PD. The results indicate that while psychotropic drugs given alone do not affect significantly the gastric mucosal barrier, they may potentiate the damaging action of ethanol on this barrier.