[Effects of modulators of calcium metabolism on mesenteric artery contractions during activation of P2X receptors in guinea-pig].

ATP evokes changes in the vascular tone through the activation of P2X and P2Y purinoceptors. To evaluate relative contribution of Ca2+ entry through the L-type voltage-gated calcium channels and Ca2+ -induced Ca2+ -release (CICR) mechanisms in initiation of vascular smooth muscle contraction induced by P2XRs activation, we have applied P2X receptor agonist -meATP (10 microM) and measured changes in phasic isometric tension of endothelium-denuded mesenteric artery rings in the presence of antagonists IP3Rs (60 mcmol/l APB) or RyRs (100 mcmol/l tetracaine) combined with on-off modulation of the L-type calcium channels by nicardipine (5 microM). We found that activation of P2XRs results in Ca2+ release from SR through both IP3Rs and RyRs.

[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.