This study was carried out ot investigate the tracheal muscle relaxation of water extracts of three kinds of Coptis rhizoma and also compare their effects with berberine and palmatine, which are the important alkaloid components of
Coptis
rhizoma, in isolated rat tracheal smooth muscle.
As a result, Coptis chinensis showed significant tracheal muscle relaxation on KC1-induced contraction and more markedly on carbachol-induced contraction in dose-dependent manner.
Coptis japonica exhibited also tracheal muscle relaxation on both contraction with slightly weaker activities than those of Coplis chinensis. The activities of the root hair of Coptis chinensis were the most weakest in three
rhizomas.
Berberine and palmatine had strong tracheal muscle relaxation, especially, on carbachol-induced contraction. However, their activities on KC1-induced contraction were weaker than that of Coptis chinensis.
The inhibitory effects of three kinds of Coptis rhizoma on the contraction by KC1 and carbachol were investigated to explain the process of their tracheal muscle relaxation. All rhizomas inhibited the contraction by both agents,
among
them, Coptis japonica showed the most significant effect, so indicating that the tracheal muscle relaxation of Coptis rhizoma may be concerned with the blocking of muscarine receptor and Ca2+ channel.
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