Hydrogenation of fluorinated molecules: an overview.

The review aims at providing an overview on the developments made in hydrogenation reactions of molecules having various fluorinated groups (F, CF3, CF2H, CF2Rf). Indeed, the hydrogenation of fluorine-containing molecules is a straightforward and atom-economical way to access challenging (chiral) fluorinated scaffolds. This promising field is still in its infancy and milestones are expected in the coming years. To illustrate that, the review will highlight the major contributions made in that field and will be organized by fluorinated groups.

Pharmacological delta1- and delta2-opioid receptor subtypes in the human neuroblastoma cell line SK-N-BE: no evidence for distinct molecular entities.

The two pharmacological delta-opioid receptor subtypes, delta1 and delta2, have been defined on the basis of pharmacological tools but remain to be characterized at the molecular level, since only a single cDNA has been cloned. The present study aimed to investigate the pharmacological properties of delta1- and delta2-opioid subtypes expressed in the human neuroblastoma cell line SK-N-BE and to characterize their putative corresponding mRNAs. Binding experiments using "selective" delta1- and delta2-opioid agonists and antagonists revealed the presence of two binding sites, demonstrating the presence of these delta1-opioid subtypes as they were previously described. The activation of these pharmacological subtypes by the selective agonists induced the incorporation of [alpha-(32)P]azidoanilide-GTP into Galpha(i2)/Galpha(0) subunits with the same efficiency and potency and inhibited adenosine 3', 5'-cyclic monophosphate (cAMP) accumulation with similar efficiency, while their sustained activation for 15 min induced a cross-desensitization. The "selective" delta1 and delta2 antagonists, 7-benzylidenenaltrexone and naltrindole benzofuran, respectively, were found to be as potent in blocking the inhibition of cAMP accumulation induced by both [D-Pen(2,5)]enkephalin and Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH(2). The possibility that delta-opioid subtypes could arise from alternative splicing was ruled out by reverse transcription-polymerase chain reaction (RT-PCR) experiments and the sequencing of PCR products, which revealed the presence of a single transcript encoding for the delta-opioid receptor. Different possibilities which could account for the delta-opioid receptor heterogeneity observed in the SN-N-BE cell line are discussed.