BACKGROUND The mechanisms of amino-amide local anesthetic agent-induced vasoconstriction remain unclear. The current study was designed to examine the roles of the protein kinase C (PKC), Rho kinase, and p44/42 mitogen-activated protein kinase (p44/42 MAPK) signaling pathways in calcium (Ca2+)-sensitization mechanisms in ropivacaine-induced vascular contraction. METHODS Endothelium-denuded ra...

Recently, we demonstrated that the GSL (glycosphingolipid), GlcCer (glucosylceramide), modulates Ca2+ release from intracellular stores and from microsomes by sensitizing the RyaR (ryanodine receptor), a major Ca2+-release channel of the endoplasmic reticulum, whereas the lyso derivative of GlcCer, namely GlcSph (glucosylsphingosine), induced Ca2+ release via a mechanism independent of the RyaR...

Compared to sham-operated controls, myofilaments from hearts of ovariectomized (OVX) rats demonstrate an increase in Ca2+ sensitivity with no change in maximum tension (Wattanapermpool J and Reiser PJ. Am J Physiol 277: H467-H473, 1999). To test the significance of this modification in intact cells, we compared intracellular Ca2+ transients and shortening of ventricular myocytes isolated from s...

BACKGROUND & OBJECTIVES The biochemical mechanisms underlying the development of sensitization-induced airway hyperresponsiveness (AHR) in asthma are poorly defined. Alterations in the regulation of intracellular calcium may play an important role in its pathogenesis. We carried out this study to see the effect of sensitization with ovalbumin on membrane ion fluxes and intracellular calcium in ...

Preincubation with an alpha 2-adrenergic agonist sensitized subsequent forskolin- and vasoactive intestinal peptide-stimulated cyclic AMP production in HT29 cells, a human colonic adenocarcinoma cell line. Preincubation with somatostatin, another agonist negatively coupled to adenylate cyclase, sensitized forskolin-stimulated cyclic AMP production to a lesser extent. alpha 2-Adrenergic agonist ...

Na+-K+-ATPase plays a major role in regulating membrane potential and vascular tone. We analyzed the modulation by norepinephrine (NE), endothelin-1 (ET-1), and phorbol 12-myristate 13-acetate (PMA) of Na+-K+-ATPase-induced cytoplasmic free Ca2+concentration ([Ca2+]i) reduction and relaxation in isolated endothelium-denuded piglet mesenteric arteries. KCl (0.2-8.8 mM)-induced [Ca2+]ireduction a...