Involvement of mu-opioid receptors in antinociception and inhibition of gastrointestinal transit induced by 7-hydroxymitragynine, isolated from Thai herbal medicine Mitragyna speciosa.

7-hydroxymitragynine, a constituent of the Thai herbal medicine Mitragyna speciosa, has been found to have a potent opioid antinociceptive effect. In the present study, we investigated the mechanism of antinociception and the inhibitory effect on gastrointestinal transit of 7-hydroxymitragynine, and compared its effects with those of morphine. When administered subcutaneously to mice, 7-hydroxymitragynine produced antinociceptive effects about 5.

Diterpenes from Leucas aspera inhibiting prostaglandin-induced contractions.

Investigation of the inhibitory fraction of Leucas aspera on prostaglandin-induced contraction in guinea pig ileum provided four new diterpenes, leucasperones A (1) and B (2) and leucasperols A (3) and B (4), and three new isopimarane glycosides, leucasperosides A, B, and C (5-7), together with the known compounds asperphenamate, maslinic acid, (-)-isololiolide, and linifolioside. The structures of the compounds were determined by detailed spectroscopic analysis. The configurations of 1 and 2 and the acetylated derivatives of 3 and 4 were determined by differential NOE analysis and CD data.

Temperature rhythm reentrains faster than locomotor rhythm after a light phase shift.

Mammalian endogenous circadian rhythms are entrained to the environmental light-dark (LD) cycle. Although the circadian rhythms of core body temperature (Tb) and spontaneous locomotor activity (LA) are well synchronized under stable LD conditions, it is thought that these two parameters are regulated by distinct mechanisms. The purpose of the present study was to examine the adaptability of these two rhythms to an abrupt change in the environmental light phase.

Involvement of hepatocyte growth factor in the development of bone metastasis of a mouse mammary cancer cell line, BALB/c-MC.

Some cancers frequently affect the skeleton, and the bone microenvironment supports growth of certain cancer cells. After tumors metastasize to bone, they stimulate osteoclastogenesis and expand in the bone tissue. Hepatocyte growth factor (HGF), which was originally identified as a potent mitogen for hepatocytes, promotes tumor growth, invasion and metastasis.

Inhibitory effect of mitragynine, an analgesic alkaloid from Thai herbal medicine, on neurogenic contraction of the vas deferens.

The effect of an indole-alkaloid mitragynine isolated from the Thai medicinal herb kratom (Mitragyna speciosa) on neurogenic contraction of smooth muscle was studied in guinea-pig vas deferens. Mitragynine inhibited the contraction of the vas deferens produced by electrical transmural stimulation. On the other hand, mitragynine failed to affect the responses to norepinephrine and ATP.