Thapsigargin-resistant thiacalix[4]arene C-1087-sensitive component of the contractile activity in rat myometrium reflects the functioning of plasma membrane calcium pump

Background. According to existing knowledge, thiacalix[4]arene С-1087 is highly capable of inhibiting Са2+-pump (Са2+, Mg2+-АТРase) the plasma membrane; at same time it inhibits functioning sarcoplasmic reticulum uterine smooth muscles some degree. The aim this research was study effects on concentration Ca2+ ions and contractile activity rat myometrium cells using an inhibitor – thapsigargin. Materials Methods. experiments were conducted outbred white non-pregnant rats. in preparations longitudinal SM horns with preserved endothelium registered isometric mode. To determine changes [Ca2+]i level, myocytes treated probes Hoechst 33342 (to test nucleus cell) fluo-4 AM change Са2+-concentration cell). Results. tenzometric studies subsequent mechanokinetic analysis demonstrated that under action thapsigargin (0.5 µM), C-1087 (10 µM) caused considerable kinetics spontaneous processes rats, including decrease maximal contraction velocity increase relaxation velocity. By means confocal microscopy Ca2+-sensitive fluorescent probe fluo-4, application immobilized uterus against background a transient spike Са2+-signal turn intracellular Ca stable increased level. regarding phase contractions removed after preliminary blocking nitric oxide synthases L-NAME (100 µM). Under L-NAME, complete inhibition process preparations, induced by high-potassium solution (80 mM). Conclusions. primary reason for Ca2+-signal effect its ability inhibit further С-1087-induced muscle tissues may be level Са2+ myocytes. obtained results demonstrate promising compound elaboration pharmacological modulating muscles, myometrium.