Abstract
The valepotriates isovaltrate and valtrate, and the essential oil compound valeranone caused a suppression of rhythmic contractions in a closed part of the guinea-pig ileum in-vivo. The same compounds and didrovaltrate relaxed potassium stimulated contractures and inhibited BaCl2 contractions in guinea-pig ileum preparations in-vitro. Guinea-pig stomach fundic strips stimulated by carbachol were also relaxed by these substances. Potassium stimulated smooth muscle cells were also relaxed by the valeriana compounds (10(-5)-10(-4) M) even, when autonomic receptors were blocked by appropriate antagonists. In lower concentrations (10(-6)-10(-5) M), the compounds did not affect the dose-response curves of carbachol and isoprenaline. In some experiments valeranone at 4.10(-6) M produced an increased isoprenaline relaxation of the guinea-pig ileum. Valeranone and didrovaltrate were about equipotent to papaverine in inhibiting BaCl2 contractions. It is concluded that the valeriana compounds probably relax stimulated smooth muscle cells by acting as musculotropic agents and not by interacting with receptors of the autonomic nervous system.
