Sevoflurane, but not propofol, prevents Rho kinase-dependent contraction induced by sphingosylphosphorylcholine in the porcine coronary artery

Role of Sphingosylphosphorylcholine in Tumor and Tumor Microenvironment

Sphingosylphosphorylcholine (SPC) is a unique type of lysosphingolipid found in some diseases, and has been studied in cardiovascular, neurological, and inflammatory phenomena. In particular, SPC’s studies on cancer have been conducted mainly in terms of effects on cancer cells, and relatively little consideration has been given to aspects of tumor microenvironment. This review summarizes the effects of SPC on cancer and tumor microenvironment, and presents the results and prospects of modulators that regulate the various actions of SPC.

Phosphatidylinositol 3-kinase inhibition induces vasodilator effect of sevoflurane via reduction of Rho kinase activity

AIMS

This study was aimed to examine whether a volatile anesthetic sevoflurane in clinical doses reduces vasoconstriction under the inhibition of phosphatidylinositol 3-kinase (PI3K) in the rat and human arteries and whether the intravenous administration of the PI3K inhibitor decreases blood pressure in rats under the sevoflurane inhalation.

MATERIALS AND METHODS

Rat arteries (n=5-6) and human omental arteries (n=5-6) were subjected to isometric force recordings and western immunoblotting for Rho kinase, mitogen-activated protein kinase, and protein kinase C. Some arteries were incubated with sevoflurane (1.5% or 3%), a selective PI3K inhibitor LY294002 (3×10^-6mol/L) or the combination. Mean arterial pressure (MAP) and heart rate (HR) in rats (n=7) were evaluated with or without intravenous injection of LY294002 (3×10^-6mol/L) under 2% sevoflurane inhalation.

KEY FINDINGS

Sevoflurane with LY294002, but not sevoflurane or LY294002 solely, inhibited the phenylephrine-induced contraction (32% to 52% decrease at phenylephrine [3×10^-6mol/L] in rat arteries and [3×10^-5mol/L] in human arteries). Sevoflurane (3%) only with LY294002 decreased Rho kinase activity in the rat aorta into 30%. Intravenous LY294002 reduced MAP (8.1-12.4mmHg decrease), but not HR, in rats under 2% sevoflurane inhalation.

SIGNIFICANCE

Clinical sevoflurane doses with PI3K inhibition reduce the contraction of rat and human arteries ex vivo resulting from Rho kinase inhibition, and systemic blood pressure of rats in vivo. These results suggest that sevoflurane potentially causes vasodilation and hypotension in patients receiving anti-cancer therapy that inhibits PI3K.