Acetylcholine stimulates selective liberation and re-esterification of arachidonate and accumulation of inositol phosphates and glycerophosphoinositol in C62B glioma cells

Glioma C62B cells, incubated for 18 h with either an unsaturated (arachidonate or oleate) or saturated (palmitate or stearate) radioactive fatty acid, incorporated label into most species of cellular glycerolipids. Treatment of prelabeled C62B cells with 1 mM acetylcholine (ACh) resulted in an accumulation of radioactive phosphatidate irrespective of which fatty acid was used as a label. However, only in cells prelabeled with unsaturated fatty acids were increases in radioactive fatty acids observed. When exogenous radioactive arachidonate was added to C62B cells in the presence of 1 mM ACh, there was a rapid, selective, and transiently enhanced incorporation of label (several times the control) into phosphatidylinositol (PI). The ACh-enhanced incorporation into PI was not preceded by enhanced incorporation of label into sn-1,2-diacylglycerol or phosphatidate but was followed by an increased labeling of polyphosphoinositides. Similarly, incorporation of oleate into PI was enhanced by ACh. In contrast, ACh did not enhance the incorporation of label into any glycerolipids when saturated fatty acids were used. C62B cells, incubated with [2-3H]inositol for 18 h selectively incorporated label into phosphoinositides. Stimulation of [2-3H]inositol-labeled cells with 1 mM ACh in the presence of 25 mM LiCl resulted in a rapid accumulation of radioactive inositol phosphates (mono-, bis-, and trisphosphates) and glycerophosphoinositol. The accumulation of inositol trisphosphates preceded that of inositol monophosphate and glycerophosphoinositol, while the accumulation of glycerophosphoinositol paralleled the time required for the ACh-stimulated esterification of arachidonate. These results suggest that ACh stimulates activation of a phospholipase C in C62B cells and release of 1,4,5-inositol trisphosphate. There is subsequent activation of phospholipase A2, which in turn liberates arachidonate from PI. The resulting lyso PI is either rapidly reesterified with unsaturated fatty acid to resynthesize PI, or further deacylated to yield glycerophosphoinositol

Business Ethics: The Promise of Neuroscience

Recent advances in cognitive neuroscience research portend well for furthering understanding of many of the fundamental questions in the field of business ethics, both normative and empirical. This article provides an overview of neuroscience methodology and brain structures, and explores the areas in which neuroscience research has contributed findings of value to business ethics, as well as suggesting areas for future research. Neuroscience research is especially capable of providing insight into individual reactions to ethical issues, while also raising challenging normative questions about the nature of moral responsibility, autonomy, intent, and free will. This article also provides a brief summary of the papers included in this special issue, attesting to the richness of scholarly inquiry linking neuroscience and business ethics. We conclude that neuroscience offers considerable promise to the field of business ethics, but we caution against overpromise

Brain Arachidonic Acid Incorporation and Turnover are not Altered in the Flinders Sensitive Line Rat Model of Human Depression

Brain serotonergic signaling is coupled to arachidonic acid (AA)-releasing calcium-dependent phospholipase A2. Increased brain serotonin concentrations and disturbed serotonergic neurotransmission have been reported in the Flinders Sensitive Line (FSL) rat model of depression, suggesting that brain AA metabolism may be elevated. To test this hypothesis, (14)C-AA was intravenously infused to steady-state levels into control and FSL rats derived from the same Sprague-Dawley background strain, and labeled and unlabeled brain phospholipid and plasma fatty acid concentrations were measured to determine the rate of brain AA incorporation and turnover. Brain AA incorporation and turnover did not differ significantly between controls and FSL rats. Compared to controls, plasma unesterified docosahexaenoic acid was increased, and brain phosphatidylinositol AA and total lipid linoleic acid and n-3 and n-6 docosapentaenoic acid were significantly decreased in FSL rats. Several plasma esterified fatty acids differed significantly from controls. In summary, brain AA metabolism did not change in FSL rats despite reported increased levels of serotonin concentrations, suggesting possible post-synaptic dampening of serotonergic neurotransmission involving AA

Evaluation of Therapeutics for Advanced-Stage Heart Failure and Other Severely-Debilitating or Life-Threatening Diseases

Severely-debilitating or life-threatening (SDLT) diseases include conditions in which life expectancy is short or quality of life is greatly diminished despite available therapies. As such, the medical context for SDLT diseases is comparable to advanced cancer and the benefit vs. risk assessment and development of SDLT disease therapeutics should be similar to that of advanced cancer therapeutics. A streamlined development approach would allow patients with SDLT conditions earlier access to therapeutics and increase the speed of progression through development. In addition, this will likely increase the SDLT disease therapeutic pipeline, directly benefiting patients and reducing the economic and societal burden of SDLT conditions. Using advanced-stage heart failure (HF) as an example that illustrates the concepts applicable to other SDLT indications, this article proposes a streamlined development paradigm for SDLT disease therapeutics and recommends development of aligned global regulatory guidance