Jean-Christophe Magnan

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Our experiments focused on the examination of the distribution of mu opioid receptor binding sites in normal human brain using the highly selective ligand [3H]DAGO, in both membrane binding assay and in vitro receptor autoradiography. Mu opioid binding sites are very discretely distributed in human brain with high densities of sites found in the posterior(More)
In guinea-pig cerebellum, saturation studies reveal that the nonselective opioid [3H]ethylketazocine has a binding capacity (R) of 6.79 pmol/g tissue which is similar to the sum of the individual R values of the mu-, delta- and kappa 1-selective opioids. Conversely, the binding parameters of the nonselective opioid [3H]bremazocine are best-fitted to a(More)
Receptor binding parameters and autoradiographic distribution of various opioid receptor sites have been investigated in normal human brain, post-mortem. [3H]DAGO, a highly selective mu ligand, binds to a single class of high affinity (Kd = 1.1 nM), low capacity (Bmax = 160 fmol/mg protein) sites in membrane preparations of frontal cortex. These sites show(More)
The electrically-evoked contractions of the rat vas deferens were selectively inhibited by beta-endorphin, the preparation being much less sensitive to enkephalins and narcotic analgesic drugs. However, introduction of D-Ala in position 2 of [Leu]-enkephalin enhanced the activity of the opioid peptide to the order of that of beta-endorphin. It is concluded(More)
In guinea-pig brain, [3H]bremazocine has a binding capacity of 27.2 pmol/g wet tissue, which is statistically different from that of [3H]ethylketazocine (14.7 pmol/g wet tissue) or the sum of the individual binding capacities of mu-, delta-, and kappa-selective ligands (15.0 pmol/g wet tissue). Saturation studies of [3H]bremazocine performed in the presence(More)
The presence of multiple opioid binding sites in human fetal brain at 20 weeks gestational age was determined using the following selective tritiated ligands: D-Ala2, N-MePhe4, Gly-ol5-enkephalin (DAGO) for the mu-type, D-Pen2, D-Pen5-enkephalin (DPDP) for the delta-type and U-69,593 for the kappa-type. [3H]DAGO and [3H]U-69,593 each bind to a single class(More)
The binding characteristics of selective and nonselective opioids have been studied in whole guinea pig spinal cord, using a computer fitting method to analyze the data obtained from saturation and competition studies. The delineation of specific binding sites labeled by the mu-selective opioid [3H]D-Ala2,MePhe4,Gly-ol5-enkephalin (Kd = 2.58 nM, R = 4.52(More)