[Expression of the cold receptor TRPM8 in the smooth muscles of the seminal ejaculatory ducts in rats].

By means of real-time RT-PCR and immunofluorscent staining combined with confocal microscopy we show for the first time the expression ofmRNA and protein ofthe cold/menthol-sensitive cationic channel, TRPM8, in the smooth muscle cells (SMC) from the epididimal and prostatic portions of the rat vas deferens. Expression of TRPM8 mRNA correlated with the expression ofmRNA for androgen receptor (AR): orchidectomy of the animals resulted in the enhancement of the expression of both mRNAs, which likely reflects specific for the vas deferens compensatory response to the decreasing levels of circulating androgens. TRPM8 protein in the SMC from both parts of the vas deferens primarily localized outside the plasma membrane (PM), however, in the SMC from prostatic portion we observed higher TRPM8 protein targeting specifically the endoplasmic reticulum and PM, where it can form functional cold/menthol-sensitive cationic channel capable of modulating contractile activity of the smooth muscle.

[Regulation of the excitability of neonatal cardiomyocytes by N-stearoyl- and N-oleoyl-ethanolamines].

N-acylethanolamines (NAE) are biologically active lipids able of modulating ion transport through the cellular plasma membrane, however specific targets of their action and signalling mechanisms involved in cardiac tissue are still poorly understood. Physiological activity of NAEs is known to depend on the level of unsaturation. Therefore, here we investigated the effects of saturated N-stearylethanolamine (NSE) and monounsaturated N-oleylethanolamine on electric excitability of neonatal rat cardiomyocytes.

[A hyperpolarization-activated current in rat menthol-sensitive sensory neurons].

In the present study we have investigated the correlation between hyperpolarization-activated current (1(h)) and menthol-activated current (I(TRPM8)) in rat dorsal root ganglion (DRG) neurons. We showed that I(h) is present in 89% of menthol-sensitive neurons which makes its presence reliable, though not absolute, criterion for pre-selection of such neurons. Endogenous I(h) recorded from different neurons exhibited variable density and activation kinetics.

[Functional identification of the TRPM8 cold receptor in rat prostate epithelial cells].

For the first time by means of electrophysiology we demonstrate functional expression of cold/menthol sensitive TRPM8 channel in secretory epithelial cells plasma membrane from rat prostate. Under whole-cell patch-clamp technique rapid cooling from 33 to 21 degrees C of freshly isolated rat prostate epithelial cells elicited the significant outward rectifying membrane current with close to 0 mV reversal potential characteristic of TRPM8 activation. Extracellular application of chemical analog of cooling, menthol (100 microM) at 33 degrees C evoked similar current responses.

[Identification of E-4031-sensitive potassium current component in murine P19 embryonic carcinoma cell line differentiated in cardiomyocytes].

Pluripotent mouse P19 embryonic carcinoma cells represent a convenient in vitro model for studying various aspects of cardiac differentiation. Here by using whole-cell patch-clamp recording we have identified the rapid delayed rectifier K+ current, I(Kr) in P19 cell induced to differentiate into cardiac phenotype by DMSO (1%). Cardiac differentiation was confirmed by the appearance of spontaneously beating cells, their morphological features, ultrastructural clusterization of mitochondria around contraction elements, expression of cardiac actin mRNAs and MLC2v, and by the presence of inward sodium and calcium currents.