Inflammatory response induced by intrapleural injection of antiserum to IgE in rat. An evaluation of the role of histamine

Role of histamine in altering fluid recycling in normal and post-traumatic rabbit peritoneum

This study aims to investigate if histamine induces electrochemical alterations in the normal and post-traumatic peritoneum. Peritoneal rabbit specimens were obtained before surgery and 10 days post-operatively and were mounted in Ussing chambers. Histamine solutions were added facing the intra-peritoneal and outer-peritoneal surface. Dimetindene maleate-, cetirizine-, and ranitidine-pretreated specimens were used to investigate histamine receptor involvement, whereas amiloride- and ouabain-pretreated specimens were used to investigate ion transportation blockage involvement. Trans-mesothelial resistance (R(TM)) was determined. Histamine-increased R(TM) intra-peritoneally and decreased it outer-peritoneally. A less intense effect was induced in post-traumatic specimens. Dimetindene maleate, cetirizine, amiloride, and ouabain totally inhibited this effect, whereas ranitidine only had a partial effect. Histamine induces electrochemical alterations in the normal and post-operative peritoneum. This effect is mediated by interaction with histamine receptors, hindering the normal process of ion trans-mesothelial transportation.

Effect of histamine on the electrophysiology of the human parietal pleura

INTRODUCTION

Histamine is involved in the pathogenesis of numerous diseases and regulates the permeability of different tissues. The aim of this study is to investigate the effects of histamine on the electrophysiology of human parietal pleura and the underlying mechanisms involved.

MATERIALS AND METHODS

Pleural specimens were obtained from patients subjected to thoracic surgery and were mounted in Ussing chambers. Histamine solutions (1μM to 1mM) were applied in native and pretreated specimens with dimetindene maleate, cetirizine, ranitidine, amiloride and ouabain. Trans-mesothelial resistance was determined (R(TM)).

RESULTS

Histamine induced a rapid R(TM) increase on the mesothelial (p = 0.008) and a decrease on the interstitial surface (p = 0.029). This effect was dose-dependent and was totally abolished by dimetindene maleate, cetirizine and amiloride and partially by ranitidine and ouabain.

CONCLUSIONS

Histamine induces acute electrochemical changes in human pleura mainly via interaction with the H(1) and partially with the H(2) histamine receptors. It also interferes with trans-cellular permeability and therefore may participate in pleural fluid recycling.

Carrageenan-stimulated release of arachidonic acid and of lactate dehydrogenase from rat pleural cells

Cells isolated from the rat pleural cavity consist mainly of macrophages, mast cells, eosinophils, and lymphocytes. Isolated pleural cells labeled with [14C]arachidonic acid released appreciable amounts (approximately 12%) of radiolabel upon exposure to pharmacological concentrations of carrageenan (1-100 micrograms/ml). The release of radiolabel was decreased by an inhibitor of phospholipase A2 (p-bromophenacyl bromide) but not by an inhibitor of arachidonate cyclooxygenase (indomethacin). The released products were arachidonic acid and, to a much lesser extent, prostaglandin E2 and leukotriene C4. The release of radiolabel was associated with release of cytosolic lactate dehydrogenase over the same range of carrageenan concentrations. Time-course studies indicated that release of radiolabel preceded that of lactate dehydrogenase. Since p-bromophenacyl bromide blocked stimulated release of radiolabel but did not prevent release of lactate dehydrogenase, it is unlikely that increase in arachidonate causes carrageenan-induced cell damage. Nevertheless, the question of whether the activation of phospholipase A2 in the pleural cells, most probably the macrophages, was sufficient to initiate the carrageenan-induced inflammatory response requires further study. Cytotoxicity which was apparent with as little as 5 micrograms/ml of carrageenan, may have been a significant consequence of carrageenan action.