Characterization of a voltage-dependent L-type calcium channel from rabbit and turtle brain.
The binding of [3H]nitrendipine to membrane preparation from turtle and rabbit brain was studied. A single population of [3H]nitrendipine binding sites was detected in both species. [3H]nitrendipine bound with high affinity to brain membrane from both rabbit and turtle, revealing a significant population of binding sites (K(D) values of 0.55 +/- 0.05 nM and 0.56 +/- 0.04 nM and Bmax values of 122 +/- 11 and 275 +/- 18 fmol/mg of protein, respectively). Displacement studies showed a similar order of potency of various unlabeled ligands against [3H]nitrendipine both in rabbit or in turtle: nitrendipine > nifedipine >or= nicardipine >> verapamil >or= diltiazem. Our results show that a two fold increment of [3H]nitrendipine binding sites exists in the turtle brain respect to the rabbit.
Costa
B
B
Istituto Policattedra di Discipline Biologiche--University of Pisa, Italy.
Giusti
L
L
Martini
C
C
Lucacchini
A
A
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020746:Calcium Channels, L-Type; D002462:Cell Membrane / Q000378:metabolism; D007700:Kinetics; D008636:Mesencephalon / Q000378:metabolism; D009568:Nitrendipine / Q000378:metabolism; D016548:Prosencephalon / Q000378:metabolism; D011817:Rabbits; D013379:Substrate Specificity; D014426:Turtles
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D009568:Nitrendipine