Background and purpose: Quercetin is a major flavonoid that contributes to the reduced risk of cardiovascular disease associated with dietary ingestion of fruits and vegetables. We have pharmacologically characterized the effect of quercetin, and its sulphate and glucuronide metabolites, on vasoconstrictor and vasodilator responses in the porcine isolated coronary artery.Experimental approach: Segments of the porcine coronary artery were prepared for either isometric tension recording or determination of cyclic GMP content. The effect of quercetin and metabolites on submaximal responses to U46619 was examined in the presence and absence of substance P, bradykinin, forskolin, sodium nitroprusside (SNP) and glyceryl trinitrate (GTN).Key results: Quercetin and quercetin 3′‐sulphate inhibited endothelin and U46619‐induced contractions with greater potency (three‐ to fivefold) against the former, while quercetin 3‐glucoronide was inactive. Quercetin enhanced both the cyclic GMP content of the artery (threefold) and cyclic GMP‐dependent relaxations to GTN and SNP (two to threefold), but forskolin‐induced relaxations were unaffected. Although the effect of quercetin was qualitatively similar to that noted for UK‐114,542, a selective inhibitor of phosphodiesterase 5, it was still evident against SNP‐induced relaxations in the presence of 10 nM UK‐114,542. Quercetin and quercetin 3′‐sulphate significantly reduced the development of GTN‐associated ‘tolerance’.Conclusions and implications: Quercetin and quercetin 3′‐sulphate inhibited receptor‐mediated contractions of the porcine isolated coronary artery by an endothelium‐independent action. Quercetin selectively enhanced cyclic‐GMP‐dependent relaxations by a mechanism not involving phosphodiesterase 5 inhibition. In addition, quercetin and quercetin 3′‐sulphate opposed GTN‐induced tolerancein vitro, which may be beneficial for patients treated for angina pectoris.

Background and purpose: The uracil nucleotides UDP and UTP have been reported to activate P2Y₂, P2Y₄and P2Y₆receptors to cause vasoconstriction. We have performed a comparative analysis of these receptors in endothelium‐denuded smooth muscle from porcine isolated coronary and ear arteries, using pharmacological and molecular tools.Experimental approach: Tissue segments were used to construct non‐cumulative concentration response curves for UTP and UDP, in the absence and presence of the P2 receptor antagonists PPADS or suramin. RT‐PCR and immunoblot analyses were employed to define gene expression and immunoreactivity for P2Y₂, P2Y₄and P2Y₆receptors.Key results: In the coronary artery, UTP‐evoked contractile responses were reduced in the presence of suramin, but not PPADS, while the smaller responses to UDP were unaffected by either antagonist. In the ear artery, contractile responses to UDP were much smaller than those to UTP; responses to UTP were inhibited by both PPADS and suramin. RT‐PCR suggested predominant expression of P2Y₂receptors in the coronary artery, while P2Y₄and P2Y₆receptor gene expression appeared equivalent in both tissues. Immunoblot analyses provided evidence for P2Y₆receptors in both tissues, with equivocal evidence of P2Y₂and P2Y₄receptor immunoreactivities.Conclusions and implications: We conclude that UTP‐evoked contraction of porcine coronary artery smooth muscle appears to be predominantly P2Y₂‐mediated, while the ear artery appears to express a uracil nucleotide‐sensitive P2 receptor(s) which fails to fit readily into the current classification.British Journal of Pharmacology(2007)150, 604–612. doi:10.1038/sj.bjp.0707120

Laboratory classes form an important aspect of bioscience education. However, this environment is challenging for students due to cognitive load and lack of confidence. Familiarising students with aspects of their laboratory classes prior to the session can improve this. This study compares the pre-laboratory scaffolding that bioscience and chemistry students experience across UK HE institutions. Typically, bioscience modules used fewer types of activities than chemistry although reading the protocol was the most common activity for both disciplines. Within bioscience, pre-laboratory activities differed by level: first year undergraduates were more likely to be asked to read the protocol, watch videos or do calculation practice in their modules whereas final year undergraduates were more likely to experience experimental design or contextualised activities. Alongside this, this paper discusses an institutional case study of the development and evaluation of technical laboratory videos as pre-laboratory scaffolding for first year students. These were found to benefit both student focus and enhance confidence: implying that using the videos impacted on cognitive load and hence learning. Exploring barriers to the uptake of these resources identified a lack of awareness of them as a major factor, suggesting that greater integration of such resources would enhance engagement and impact.