Sensitivity of myometrium to CGRP varies during mouse estrous cycle and in response to progesterone

Calcitonin gene-related peptide (CGRP) inhibits contractions of the myometrium. Isometric force measurements on myometrial strips were carried out to monitor the inhibitory capacity of CGRP in the myometrium during the estrous cycle and in response to estrogen and progesterone in ovariectomized mice. CGRP inhibition of KCl-induced contractions was lowest at estrus and significantly increased during metestrus and diestrus. Progesterone treatment of ovariectomized mice resulted in a significant increase in the responsiveness of the myometrium to CGRP. Expression of CGRP-receptor component protein (CGRP-RCP), a marker of CGRP-receptor expression, was quantitated by Western and Northern blot analyses. The levels of inhibition exerted by CGRP during the various stages of the estrous cycle and in response to steroid hormone treatment correlated with the protein levels of CGRP-RCP. The mRNA levels did not change significantly during the estrous cycle or in response to hormone treatment, indicating that the regulation of CGRP-RCP protein does not occur at the transcriptional level. CGRP had an inhibitory effect both when applied before the stimulus for contraction and when applied during a sustained contracture induced by KCl. This suggests that CGRP-induced generation of second messengers can influence late events in electro-/chemomechanical coupling and/or the contractile machinery directly

Hexadecylphosphocholine inhibits invasion of mouse T-cell lymphoma cells in two different invasion assays

Hexadecylphosphocholine (HePC), an ether lipid analogue, is a new antineoplastic drug which has been shown to exert a remarkable antiproliferative effect in vitro and in vivo. The signal transduction pathway and the phospholipid synthesis are thought to be the main putative molecular targets of HePC, yet the exact mechanism of action is still unclear. To investigate the antiinvasive activity of HePC on a mouse T-cell lymphoma cell line (BW-O-Li1), we used a type I collagen gel and devitalized dermis as substrate to evaluate the migration of BW-O-Li1 after exposure to HePC. BW-O-Li1 cells were exposed for 24 h to a non-cytotoxic (10 μM) as well as to cytotoxic concentrations of HePC. Afterwards, BW-O-Li1 cells were seeded on top of a reconstituted collagen gel layer or pippeted into a steel ring placed on the dermal site of a devitalized dermis. Lymphoma cells, which invaded the collagen layer were counted by light microscopy, invasion into devitalized dermis was measured by an image analysis system. Compared to unexposed cells, invasion into the collagen gel differed significantly even at 10 μM HePC, whereas the absolute number of invading cells, independently of the HePC concentration, showed no difference in the amount of counted cells. Migration into devitalized dermis was significantly reduced for 10 μM and 40 μM HePC. These data show that complementary information can be obtained by application of the two invasion assays and that the antiinvasive effect of HePC emerges at non-cytotoxic concentrations of the substance