Review submerged speleothems and sea level reconstructions: A global overview and new results from the mediterranean sea

This study presents a global overview of the submerged speleothems used to reconstruct paleo sea levels and reports new results from two stalactites collected in the Mediterranean Sea. Coastal cave deposits significantly contributed to the understanding of global and regional sea-level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. The results indicate that submerged speleothems represent extraordinary archives that can provide detailed information on former sea-level changes. The two stalactites collected in the central Mediterranean Sea, at Favignana and Ustica islands (Sicily, Italy), are both characterized by continental, phreatic or marine layers. The U-Th and14C ages of the new speleothems provide results of great interest for relative sea-level changes over the last 1000 years

GABAB receptor antagonism by resolved (R)-saclofen in the guinea pig ileum

The GABAB receptor antagonist saclofen (3-amino-2-(4-chlorophenyl)propylsulphonic acid) has been resolved by chiral high-performance liquid chromatography. The enantiomer (R)-saclofen, but not (S)-saclofen, reversibly antagonised the (R,S)-baclofen-induced depression of cholinergic twitch contractions in the guinea-pig ileum with an apparent pA2 of 5.3. Also, 2-hydroxy-saclofen was resolved by the same method, its (S)-enantiomer yielding an apparent pA2 of 5.0. This method provides a convenient resolution of these antagonists.Kerr, David I.B. ; Ong, Jennifer ; Vaccher, Claude ; Berthelot, Pascal ; Flouquet, Nathalie ; Vaccher, Marie-Pierre ; Debaert, Miche

GABAB receptor antagonism by 7-MBFG, a benzo[b]furan analogue of baclofen, in central and peripheral tissues

(R,S)-4-Amino-3-(7-methylbenzo[b]furan-2-yl)-butanoic acid (7-MBFG), a new benzofuran analogue of the GABA(B) receptor agonist baclofen, has been evaluated for pharmacological activity on GABA(B) receptors in the guinea-pig isolated ileum and rat neocortical slices. 7-MBFG (300 and 500 microM) reversibly antagonized the (R,S)-baclofen induced depression of cholinergic twitch contractions in the guinea-pig ileum and shifted the concentration-response curve for baclofen to the right, in a parallel manner, giving an apparent pA2 value of 3.7+/-0.3. Likewise, 7-MBFG (300 and 500 microM) reversibly blocked the baclofen-induced suppression of spontaneous discharges, in rat neocortical slices maintained in Mg2+ -free Krebs medium, and caused a rightward, parallel shift of the baclofen concentration-response curve, giving an apparent pA2 value of 4.1+/-0.1. The compound 7-MBFG belongs to a novel, new class of antagonist at central and peripheral GABA(B) receptors, in which the antagonist properties reside in the pseudo-aromatic character of their 3-benzo[b]furan-2-yl substituents, and might provide useful leads for further development of GABA(B) receptor ligands.Ong, Jennifer ; Kerr, David I. ; Ansar, M'hammed ; Vaccher, Claude ; Berthelot, Pasca