The current study examined whether adolescent rats are more vulnerable than adult rats to the lasting adverse effects of cannabinoid exposure on brain and behavior. Male Wistar rats were repeatedly exposed to D-9-tetrahydrocannabinol (D 9 -THC, 5 mg/kg i.p.) in a place-conditioning paradigm during either the adolescent (post-natal day 28 + ) or adult (post-natal day 60 + ) developmental stages. Adult rats avoided a D 9 -THC-paired environment after either four or eight pairings and this avoidance persisted for at least 16 days following the final D 9 -THC injection. In contrast, adolescent rats showed no significant place aversion. Adult D 9 -THC-treated rats produced more vocalizations than adolescent rats when handled during the intoxicated state, also suggesting greater drug-induced aversion. After a 10-15 day washout, both adult and adolescent D 9 -THC pretreated rats showed decreased social interaction, while only D 9 -THC pretreated adolescent rats showed significantly impaired object recognition memory. Seventeen days following their last D 9 -THC injection, rats were euthanased and hippocampal tissue processed using two-dimensional gel electrophoresis proteomics. There was no evidence of residual D 9 -THC being present in blood at this time. Proteomic analysis uncovered 27 proteins, many involved in regulating oxidative stress/mitochondrial functioning and cytoarchitecture, which were differentially expressed in adolescent D 9 -THC pretreated rats relative to adolescent controls. In adults, only 10 hippocampal proteins were differentially expressed in D 9 -THC compared to vehicle-pretreated controls. Overall these findings suggest that adolescent rats find repeated D 9 -THC exposure less aversive than adults, but that cannabinoid exposure causes greater lasting memory deficits and hippocampal alterations in adolescent than adult rats.

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BACKGROUND Visit-to-visit clinic blood pressure variability (BPV) and 24-hour BPV have both been identified as independent risk factors for cardiovascular (CV) morbidity and mortality; however the mechanisms contributing to the increased CV risk as yet are unclear. The purpose of this study was to assess the relationship between BPV and endothelial function in a cohort of putatively healthy African Americans. METHODS 36 African Americans who were sedentary, non-diabetic, non-smoking, free of cardiovascular and renal disease and not on antihypertensive medication followed an American Heart Association low fat, low salt diet for 6 weeks. Upon completion of the 6-week dietary stabilization period, participants underwent 24-hour ambulatory BP monitoring and had their office BP measured on three separate days. Right brachial artery diameter was assessed at rest, during reactive hyperemia (flow-mediated dilation: FMD), and after nitroglycerin administration (nitroglycerin-mediated dilation: NMD). RESULTS Participants classified as having decreased endothelial function according to either %FMD or the FMD/NMD ratio had significantly higher 24-hour BPV and a trend for higher visit-to-visit BPV when compared to participants with normal endothelial function. Continuous variable analyses revealed a significant positive association between NMD and 24-hour diastolic BPV (DBPV). Visit-to-visit systolic BPV (SBPV), 24-hour SBPV, and 24-hour DBPV were all negatively associated with the FMD/NMD ratio. All relationships remained significant after adjustment for age, BMI, and mean BP levels. CONCLUSIONS These results may suggest that BPV is in increased in African Americans with decreased endothelial function and is associated with the vascular smooth muscle response to nitric oxide.

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Numerous assay methods have been developed to identify small-molecule effectors of protein kinases, but no single method can be applied to all isolated kinases. The authors developed a set of 3 high-throughput screening (HTS)-compatible biochemical assays that can measure 3 mechanistically distinct properties of a kinase active site, with the goal that at least 1 of the 3 would be applicable to any kinase selected as a target for drug discovery efforts. Two assays measure catalytically active enzyme: A dissociation-enhanced lanthanide fluoroimmuno assay (DELFIA) uses an antibody to quantitate the generation of phosphorylated substrate; a second assay uses luciferase to measure the consumption of adenosine triphosphate (ATP) during either phosphoryl-transfer to a peptide substrate or to water (intrinsic ATPase activity). A third assay, which is not dependent on a catalytically active enzyme, measures the competition for binding to kinase between an inhibitor and a fluorescent ATP binding site probe. To evaluate the suitability of these assays for drug discovery, the authors compared their ability to identify inhibitors of a nonreceptor protein tyrosine kinase from the Tec family, interleukin-2-inducible T cell kinase (ITK). The 3 assays agreed on 57% of the combined confirmed hit set identified from screening a 10,208-compound library enriched with known kinase inhibitors and molecules that were structurally similar. Among the 3 assays, the one measuring intrinsic ATPase activity produced the largest number of unique hits, the fewest unique misses, and the most comprehensive hit set, missing only 2.7% of the confirmed inhibitors identified by the other 2 assays combined. Based on these data, all 3 assay formats are viable for screening and together provide greater options for assay design depending on the targeted kinase. (Journal of Biomolecular