Effects of watery fractions of peat on the contraction activity of smooth muscles

Introduction: In the literature there are many discourses on the clinical use of peat and various peat applications in gynaecology. But there is only few information on the mechanisms of the effects. The aim of this study is the analysis of the effects of peat extracts on guinea-pig stomachs. This object was chosen for two reasons: Firstly, the changes of the contraction activity of smooth muscles play an important role in many gynaecological diseases where peat is used. Secondly the smooth muscles of guinea-pig stomachs are well-known objects. They show phasic and tonic activity so that the results can be interpreted very well. Objective: The purpose of this study is to conclude on the mode of action of peat extracts by analyzing their effects on the contractility of smooth muscle fibres. Methods: The results show that a dose of 5 mu l peat extract in 15 mi organ bath causes spontaneous contraction activity. The maximum effect was caused by a dose of 500-600 mu l which corresponds to a peat concentration of 3.3%. From the course of the dose-effect graph it can be concluded that it is probably a specific competitive effect. The watery fractions showed a spontaneous activity up to 50% of the maximal activity caused by 10(-5) M acetylcholine. We found an excitation effect in all fractions. By HPLC, however, substances with a molecular weight less than 3,000 Dalton, showed also an inhibiting effect. Conclusions: The above-mentioned stimulating effects show that there are biological active substances in peat which can influence the contractile activity of the smooth muscle fibre.