This finding suggested that certain membrane constituents diminished the stimulatory effect of Ca2+. In the present studies, we examined the effects of membrane fractions from COS-7 cells and brain tissue on the purified recombinant rat NAPE-PLD. and found that heat-stable membrane component(s) dose-dependently activated NAPE-PLD up to 4.8-5.0 fold. In the presence of the membrane fractions, however, the stimulatory effect Smoothened inhibitor of Ca2+ on the purified NAPE-PLD was considerably reduced. When it was examined if the membrane fractions can be replaced with various pure phospholipids, phosphatidylethanolamine activated NAPE-PLD up to 3.3 fold, which was followed by

decrease in the stimulatory effects of Ca2+ and several other divalent cations. These results suggest that membrane components including phosphatidylethanolamine keep the membrane-associated form of NAPE-PLD constitutively active. (c) 2007 Elsevier Ltd. All rights reserved.”
“The effect of insulin on the vasoconstriction induced by norepinephrine is at present controversial. We have previously demonstrated that high-concentration insulin may induce an increased reactivity to norepinephrine in mesenteric small resistance arteries of spontaneously hypertensive

rats. The aim of the present study was VEGFR inhibitor to evaluate the effects of low- and high-concentration insulin on the concentration-response curves to norepinephrine and acetylcholine in subcutaneous small resistance arteries of hypertensive and diabetic patients. Twelve normotensive subjects (NT), 11 patients with essential hypertension (EH), 8 patients with noninsulin-dependent diabetes mellitus (NIDDM), and 8 patients with both EH and NIDDM (EH + NIDDM) were included in the study. Subcutaneous small resistance arteries were dissected and mounted on an isometric myograph. Concentration-response curves to norepinephrine (from 10(-8) to 10(-5) mol/l) and acetylcholine (from 10(-9) to 10(-5) mol/l) were performed in the presence or absence of insulin 715 pmol/l (low concentration) and 715

nmol/l (high concentration). A significant reduction in the contractile pentoxifylline response to norepinephrine was observed in NT after preincubation of the vessels with both low- and high-concentration insulin. No reduction was observed in NIDDM and EH + NIDDM, while a significant decrease was obtained in EH with high-concentration insulin. Moreover, a significant difference in reduction in contractile response at maximal concentration of norepinephrine in the presence of low- concentration insulin was observed in NT compared to EH (p = 0.03), NIDDM (p = 0.02), and EH + NIDDM (p = 0.05), whereas no difference was observed with high-concentration insulin. No differences in the concentration-response curves to acetylcholine before or after precontraction with either low- or high-concentration insulin were observed in any group.