Binding of the benzodiazepine ligand [3H]-RO 15-1788 to membrane preparations of the rabbit and turtle retina.
1. We have studied the binding of [3H]-RO 15-1788 to membrane preparations of the retina of rabbit (Lepus cunicula) and turtle (Pseudemys scripta elegans). 2. In both species, [3H]-RO 15-1788 binding was maximal at 0 degrees C and decreased with increasing temperature. It was saturable, protein concentration-dependent and specific. Flunitrazepam, unlabelled RO 15-1788 and ethyl-beta-carboline were the most effective displacers, whereas RO 5,4864 was ineffective. 3. In both turtle and rabbit retina, Scatchard analysis indicated the presence of a single binding site for [3H]-RO 15-1788. The KD was 0.75 nM in both turtle and rabbit, while the Bmax were 520 and 250 fmol/mg protein in turtle and rabbit respectively. A study of the association rate of [3H]-RO 15-1788 binding revealed faster kinetics in turtle, as compared to rabbit.
Istituto Policattedra di Discipline Biologiche dell'Università di Pisa, Italy.
G
G
Giannaccini
M
M
Giacomelli
C
C
Martini
A
A
Lucacchini
M
M
Piccolino
D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D005442:Flumazenil / Q000378:metabolism*; D011817:Rabbits / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*; D013045:Species Specificity; D013696:Temperature; D014426:Turtles / Q000378:metabolism*
D011963:Receptors, GABA-A; D005442:Flumazenil