Un cas particulier d'utilisation du Tâbiya dans l'architecture castrale d'al-Andalus : la Sierra de los Filabres (Almer\'ia)

M. HammamInternational audienc

Un cas particulier d'utilisation du Tâbiya dans l'architecture castrale d'al-Andalus : la Sierra de los Filabres (Almer\'ia)

M. HammamInternational audienc

Smoothened titania particles to improve radionuclide separation and their application to the development of a novel [68Ge]/[68Ga] generator

LDM TEPInternational audienc

Gallium-68 Complexes Conjugated to Pittsburgh Compound B: Radiolabeling and Biological Evaluation

LDM TEPInternational audienc

A study of NPY-mediated contractions of the porcine isolated ear artery

1. Enhanced contractions of the porcine isolated ear artery by the α(2)-adrenoceptor agonist UK14304 are uncovered by pharmacological manipulation. As both neuropeptide Y (NPY) receptors and α(2)-adrenoceptors are negatively-coupled to adenylyl cyclase in this tissue, we determined whether NPY is also able to produce an enhanced contraction in the same tissue, under the same conditions. 2. NPY (0.1 μM) produced a small contraction of porcine isolated ear arteries which was 5.1±0.8% of the response to 60 mM KCl (n=14). An enhanced NPY response was uncovered if the tissue was pre-contracted with 0.1 μM U46619, and relaxed back to baseline with 1–2 μM forskolin before the addition of NPY (49.8±5.3%, n=14). 3. Forskolin (1 μM) stimulated cyclic AMP accumulation in porcine ear artery segments in the presence of 0.1 μM U46619 and 1 mM isobutylmethylxanthine (IBMX), NPY (0.1 μM) inhibited this response by 40%, but had no effect on basal levels of cyclic AMP. 4. An enhanced response to 0.1 μM NPY was also obtained after pre-contraction with 0.1 μM U46619 and relaxation with either SNP (28.9±5.7%, n=14), or dibutyryl cyclic AMP (21.2±4.6%, n=14). This indicates that at least part of the enhanced response to NPY is independent of the agonist's ability to inhibit adenylyl cyclase. 5. In conclusion, an enhanced contraction to NPY in the porcine isolated ear artery can be obtained by prior pharmacological manipulation. The enhanced responses are mediated through adenylyl cyclase-dependent and independent pathways similar to those reported for α(2)-adrenoceptors in this preparation

8 | Aurès – Azrou

Ouvrage publié avec le concours et sur la recommandation du Conseil international de la philosophie et des sciences humaines (UNESCO). Ce volume, à l'origine publié par Edisud, est désormais diffusé par les Editions Peeters sous l'ISBN 978-2-85744-461-

α(2)-Adrenoceptor and NPY receptor-mediated contractions of porcine isolated blood vessels: evidence for involvement of the vascular endothelium

1. Enhanced contractions to the α(2)-adrenoceptor agonist UK14304 and neuropeptide Y (NPY) in the porcine ear artery can be uncovered by pharmacological manipulation. The aim of this study was to determine whether similar pharmacological manipulation can uncover enhanced contractions in the porcine splenic artery, and to determine whether the endothelium modulates these responses. 2. UK14304 (0.3 μM) and NPY (0.1 μM) produced small contractions of the porcine splenic artery. After pre-contraction of the tissue with U46619, followed by relaxation with forskolin, the responses to both UK14304 and NPY were enhanced. Enhanced contractions to both UK14304 and NPY were also obtained after relaxation with SNP. These results demonstrate that, as in the porcine ear artery, α(2)-adrenoceptors and NPY receptors are able to produce enhanced contractile responses through both adenylyl cyclase-dependent and -independent signal transduction pathways. 3. Removal of the endothelium had no significant effect on responses to UK14304 either alone or in the presence of U46619 and forskolin in the porcine splenic artery. On the other hand, responses to UK14304 after relaxation with SNP were reduced after endothelium-denudation in both the porcine splenic artery and ear artery. Similar results were obtained with NPY in the porcine ear artery. 4. In conclusion, enhanced contractile responses to UK14304 and NPY in the porcine splenic artery can be uncovered using methods similar to those employed in the porcine ear artery. Under certain conditions the responses to both agents are modulated by the endothelium. These data highlight further the similarities in the signal transduction pathways used by both α(2)-adrenoceptors and NPY receptors to induce vasoconstriction