Influence of halothane on phospholipase A2 and enzymatic methylations in the rat retinal membranes.

Phospholipase A2 (PLA2) and phospholipid methylases (PLM) play significant roles in transmitter release and membrane signal transduction, respectively. Previous studies have indicated that PLMs occur in the rat brain synaptosomal and retinal membranes, and they are activated under halothane anesthesia. The influence of halothane on PLA2 is not known.

Prostaglandin E2 in human placenta: its vascular effects and activation of prostaglandin E2 formation by nicotine and cotinine.

Tobacco smoking by pregnant women increases the frequency of spontaneous abortions and preterm births. Human labor is associated with enhanced intrauterine phospholipid metabolism and production of prostaglandin E2 (PGE2) which induces labor, initiates uterine contractions and maintains the homeostasis of placental blood flow. Therefore, we studied: (a) the influence of nicotine and cotinine on the effects of PGE2 on placental vasculature in perfused human placental cotyledon, and (b) the activation of placental phospholipase A2 (PLA2) by nicotine and cotinine using 1-palmitoyl-2-[1-14C]arachidonyl-phosphatidylethanolamine (PE, 2.

Influence of nicotine and cotinine on retinal phospholipase A2 and its significance to macular function.

The macula is a constituent of the sensory retina that is necessary for sharp contrast and color vision. A significant relationship has been found between tobacco smoking and age-related macular degeneration. Opsin, rhodopsin and phospholipase A2 (PLA2) are located in excitable membranes of retina which are enriched with polyunsaturated fatty acids (PUFA).

Formation and retention of cotinine during placental transfer of nicotine in human placental cotyledon.

Maternal smoking during pregnancy causes reduction of fetal breathing movements, an effect attributed to nicotine in fetal blood. Nicotine is metabolized to cotinine which has a long plasma half-life and exhibits slow clearance across membrane barriers. It is also known to activate placental phospholipase-A2-like enzymes, resulting in formation of prostaglandins.

Dual messenger function for prostaglandin E2 (PGE2) in human placenta.

There is periparturitional increase of prostaglandin E2 (PGE2) in the plasma and amniotic fluid of humans. PGE2 increases uterine contractions and also increases uterine blood flow to sustain the contractions. A question arises as to what role PGE2 plays in human placental circulation.