[The effect of the beta adrenomimetic trimethoquinol and its rigid tetrahydroberberine conformer on histamine liberation induced by compound 48/80 in mast cells].

The effects of the beta 2-adrenomimetic trimethoquinol (TMQ) and one of its rigid tetrahydroprotoberberin conformer - compound Is-35 - on the histamine content and the compound 48/80 induced histamine release have been studied. The histamine content in skin parts of ears and in the whole heart of male rats has been determined spectro-photofluorometrically. TMQ and Is-35 were injected in doses of 3 mumol/kg and compound 48/80 in increasing doses (1, 2 and 3 mg/kg) during 3 successive days. It has been found that the antagonizing effect of TMQ on the mast cell histamine release is tissue-dependent: it prevents the release of 20% of the compound 48/80-releasable histamine in ears and of 40% in heart. Is-35 has not effect on the compound 48/80 induced histamine release in ears and prevents the release of only 12% of the compound 48/80-releasable histamine in heart. The morphological studies show quantitative and qualitative changes in the heart mast cell population which are in good agreement with the biochemical data obtained. The fixation of the flexible part of the TMQ molecule in a tetrahydroprotoberberin configuration results in a reduction of the antagonistic activity towards the compound 48/80 induced histamine release. On the basis of this finding it could be suggested that an aporphin-like conformation of the TMQ molecule is responsible for its activity established.