Localization of N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) expression in mouse brain: A new perspective on N-acylethanolamines as Neural Signaling Molecules

The definitive version is available at www3.interscience.wiley.co

Release of anandamide from blood cells

Background: Endogenous ligands of cannabinoid receptors ( endocannabinoids), in particular anandamide ( arachidonylethanolamide), have been recognized as being of crucial importance in a variety of physiological functions. Plasma concentrations of anandamide have been measured in a number of investigations; however, discrepant data on "normal'' anandamide plasma concentrations were reported. Since this might be caused by pre-analytical variables, we investigated the impact of different sample handling conditions on measured plasma anandamide concentrations. Methods: Blood samples were taken from healthy volunteers in EDTA- or heparin-containing tubes; whole blood samples were kept at +4 degrees C, room temperature, or 37 degrees C, respectively, for up to 120 min before obtaining plasma by centrifugation. Plasma anandamide concentrations were measured by an isotope-dilution liquid chromatography tandem mass spectrometry ( LC-MS/MS) method. Results: A marked time- and temperature-dependent increase in plasma anandamide concentrations ex vivo was observed in both EDTA- and heparin-containing tubes. Mean anandamide concentrations approximately doubled when EDTA samples were kept at 4 degrees C for 60 min before centrifugation {[}immediately centrifuged, 1.3 mg/L ( SD 0.3 mg/L); 2.8 mg/L ( SD 0.5 mg/L) after storage for 60 min; n=12). After storage of heparinized whole-blood samples for 120 min at 37 degrees C, a mean plasma anandamide concentration of 11.9 mg/L ( SD 1.8 mg/L) was found. In cell-free plasma, no increase in anandamide concentrations was found. Conclusion: Anandamide is released from blood cells ex vivo at a very high rate; therefore, strictly standardized pre-analytical protocols have to be applied for plasma anandamide determination

The sleep-inducing lipid oleamide deconvolutes gap junction communication and calcium wave transmission in glial cells.

Oleamide is a sleep-inducing lipid originally isolated from the cerebrospinal fluid of sleep-deprived cats. Oleamide was found to potently and selectively inactivate gap junction-mediated communication between rat glial cells. In contrast, oleamide had no effect on mechanically stimulated calcium wave transmission in this same cell type. Other chemical compounds traditionally used as inhibitors of gap junctional communication, like heptanol and 18beta-glycyrrhetinic acid, blocked not only gap junctional communication but also intercellular calcium signaling. Given the central role for intercellular small molecule and electrical signaling in central nervous system function, oleamide- induced inactivation of glial cell gap junction channels may serve to regulate communication between brain cells, and in doing so, may influence higher order neuronal events like sleep induction

Ligands in crystal structures that aid in functional characterization

An overview and commentary on the value of liganded structures emerging from the JCSG structural genomics initiative

Field and Laboratory Evaluation of an Industrial Effluent Containing Elevated Levels of Ammonia

This study evaluated the effects of an industrial wastewater effluent that contains varying levels of ammonia on the biota in a reach of the Verdigris River in Oklahoma. This investigation was undertaken using both laboratory toxicity tests, as well as field site monitoring including community assessments and in situ techniques, water quality monitoring, macroinvertebrate and fish community sampling and an in situ zebra mussel (Dreissena polymorpha) study. A series of 48-hr laboratory bioassays using the fathead minnow (Pimephales promelas) were performed in unadjusted and pH manipulated effluent and laboratory water (pH 8.5 and 9.0). Additionally ammonia levels (total) were adjusted to 10, 20 and 30 mg NH3-N/L, for another series of toxicity tests with both unadjusted and manipulated test waters. Unadjusted (pH) effluent at all ammonia levels showed no toxicity until total ammonia levels reached 30 mg NH3-N/L (65.2%) whereas at pH 8.5 LC50 values at 20 and 30 mg NH3-N/L total ammonia were 58.5% and 38.1%, respectively. The largest effect on toxicity was observed in the effluent at pH 9.0 with LC50 values of 66.4% at 10mg/L, 23.1% at 20 mg/L and 16.2% at 30 mg/L total ammonia. The ammonia solutions were generally more toxic to the fathead minnows than the effluent samples with similar ammonia concentrations, which could be an indication that the effluent matrix ameliorated ammonia toxicity. In the on-site field study, there were no significant differences at the effluent outflow site compared with sites up and down-river on the macroinvertebrate communities, zebra mussel growth and wet: dry weight, although the effluent did attract more fish in the immediate vicinity of the outflow (not significant). Overall, the results from the study indicate the effluent is not having any significant adverse effects on the receiving system.Environmental Sciences Progra

Stress Promotes Drug Seeking Through Glucocorticoid-Dependent Endocannabinoid Mobilization in the Prelimbic Cortex

Background Clinical reports suggest that rather than directly driving cocaine use, stress may create a biological context within which other triggers for drug use become more potent. We hypothesize that stress-induced increases in corticosterone “set the stage” for relapse by promoting endocannabinoid-induced attenuation of inhibitory transmission in the prelimbic cortex (PL). Methods We have established a rat model for these stage-setting effects of stress. In this model, neither a stressor (electric footshock) nor stress-level corticosterone treatment alone reinstates cocaine seeking following self-administration and extinction, but each treatment potentiates reinstatement in response to an otherwise subthreshold cocaine priming dose (2.5 mg/kg, intraperitoneal). The contributions of endocannabinoid signaling in the PL to the effects of stress-level corticosterone on PL neurotransmission and cocaine seeking were determined using intra-PL microinfusions. Endocannabinoid-dependent effects of corticosterone on inhibitory synaptic transmission in the rat PL were determined using whole-cell recordings in layer V pyramidal neurons. Results Corticosterone application attenuated inhibitory synaptic transmission in the PL via cannabinoid receptor type 1 (CB1R)– and 2-arachidonoylglycerol–dependent inhibition of gamma-aminobutyric acid release without altering postsynaptic responses. The ability of systemic stress-level corticosterone treatment to potentiate cocaine-primed reinstatement was recapitulated by intra-PL injection of corticosterone, the CB1R agonist WIN 55,212-2, or the monoacylglycerol lipase inhibitor URB602. Corticosterone effects on reinstatement were attenuated by intra-PL injections of either the CB1R antagonist, AM251, or the diacylglycerol lipase inhibitor, DO34. Conclusions These findings suggest that stress-induced increases in corticosterone promote cocaine seeking by mobilizing 2-arachidonoylglycerol in the PL, resulting in CB1R-mediated attenuation of inhibitory transmission in this brain region