[Role of the French national registry REIN in the health monitoring of patients with end-stage chronic renal failure infected with SARS-CoV-2: Organization and initial data].

The REIN registry is a national registry held by the French Biomedicine Agency. Its objective is the epidemiological monitoring of patients with end-stage chronic renal failure. This registry, backed by its expertise and its national network, has been able to very quickly set up epidemiological monitoring of chronic dialysis and/or transplant patients affected by SARS-CoV-2.

Distinct mechanisms for activation of the opioid receptor-like 1 and kappa-opioid receptors by nociceptin and dynorphin A.

To understand how two structurally analogous ligand-receptor systems, the nociceptin/opioid receptor-like 1 (ORL1) and dynorphin A/kappa-opioid receptor 1 (KOR1) systems, achieve selectivity, receptor chimeras were generated and analyzed. Replacing discrete domains located between the N-terminus and top of the third transmembrane helix of the KOR1 by the homologous domains of the ORL1 receptor yields hybrid receptors, which, in comparison with the parent KOR1, display up to 300-fold increased affinity but low sensitivity toward nociceptin, and unaltered (high) affinity and sensitivity toward dynorphin A. These substitutions contribute elements for binding of nociceptin but do not suppress determinants necessary for binding and potency of dynorphin A.

Different domains of the ORL1 and kappa-opioid receptors are involved in recognition of nociceptin and dynorphin A.

In order to gain further insight into the functional architecture of structurally related G protein-coupled receptors, the ORL1 (nociceptin) and opioid receptors, we have constructed chimeras of ORL1 and mu-, delta- and kappa-opioid receptors, and compared their binding and functional properties with those of the parent receptors. We find in particular that a ORL1-kappa-opioid (O-K) hybrid construct has retained high affinity for non-type-selective opiate ligands, and has acquired the ability to bind and respond to enkephalins and mu- and/or delta-opioid receptor-selective enkephalins analogs, thus behaving like a 'universal' opioid receptor. Most significantly however, whilst the ORL1 and kappa-opioid receptors display high binding preference (KD 0.

Comparison of the structure-activity relationships of nociceptin and dynorphin A using chimeric peptides.

The aim of the present study was to delineate the functional domains of nociceptin (noc), a neuropeptide which is structurally related to dynorphin A (dyn). The binding and biological potencies towards the nociceptin (ORL1) and dynorphin A (kappa-opioid) receptors of twenty dyn/noc and noc/dyn hybrid peptides were compared with those of the parent heptadecapeptides. Replacement of as many as eleven residues in the C-terminus of dynorphin by the corresponding nociceptin sequence has no significant effect on binding and biological activity towards the kappa-opioid receptor.