Important advances have recently been made in our understanding of the arachidonic acid cascade. The molecular characterization of different forms of phospholipase A2 indicates that multiple pathways are involved in the release of arachidonic acid evoked by physiological or pathological stimuli. Moreover, studies on the expression of enzymes that metabolize arachidonic acid reveal the potential participation of the eicosanoids in central aspects of cell regulation, such as control of mitogenesis. Finally, cloning of the first eicosanoid receptors is a major step towards elucidating the diverse cellular functions exerted by these bioactive lipids.

This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library.

Endogenous marijuana-like compounds regulate implantation during pregnancy by activating cannabinoid receptors on the embryo's surface. A new study explores the dynamics of this process and renews concerns about marijuana use in pregnant women.

Recent evidence suggests that the endogenous activators of neuronal vanilloid (capsaicin) receptors should be sought inside, not outside, the neuron. 12-Lipoxygenase metabolites of arachidonic acid, produced by pain-inducing mediators such as bradykinin, might trigger vanilloid receptor activation by interacting with an intracellular site on the receptor. Are these lipid-like second messengers the long-sought endogenous vanilloids?

After many years backstage, lipids have made a come back in the limelight of neuroscience. This renewed excitement was sparked by a series of convergent discoveries in the fields of neural development, synaptic physiology and receptor pharmacology, which have begun to reveal the roles played by lipid messengers and their receptors in brain function. Such roles extend from the development of the neocortex to the processing of complex behaviors, encompassing a territory as vast as those traditionally assigned to growth factors, neurotransmitters and neuropeptides. Along with these basic discoveries, technical advances have simplified the identification and quantification of neural lipids, achieving a degree of sensitivity and selectivity that was unthinkable only 10 years ago. Thanks to this progress, we can now resolve complex mixtures of lipid molecules and quantify each of their components, which are often present in tissues at vanishingly low concentrations. In this review, I outline several key features of brain lipid signaling and discuss the opportunities and challenges that such features impose on future lipidomic approaches.

This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library.