Melatonin-induced glycosaminoglycans augmentation in myocardium remote to infarction.

M to 10 –6 M was applied to the fibroblast cultures. In the final part of the study, the influence of luzindole (10 –6 M), the melatonin membrane receptor inhibitor, on melatonin-induced GAG augmentation was investigated. Both collagen and GAG content were measured in the experiment. Melatonin elevated GAG content in the myocardium remote to the infarcted heart. Collagen level was not changed by pineal indoleamine. Fibroblasts isolated from the myocardium varied in shape from fusiform to spindle-shaped. Moreover, the pineal hormone (10 –7 M and 10 –6 M) increased GAG accumulation in the fibroblast culture. Luzindole inhibited melatonin-induced elevation of GAG content at 10 –6 M. Melatonin increased GAG content in the myocardium remote to infarction. This effect was dependent on the direct influence of the pineal indole on the heart fibroblasts. The melatonin-induced GAG elevation is blocked by luzindole, the melatonin membrane receptors inhibitor, indicating a direct effect of this indole.