Novel tacrine derivatives that block neuronal calcium channels.
A new series of tacrine (9-amino-1,2,3,4-tetrahydroacridine) derivatives were synthesized and their effects on 45Ca(2+) entry into bovine adrenal chromaffin cells stimulated with dimethylphenylpiperazinium (DMPP) or K(+), studied. At 3 microM, compound 1 did not affect (45)Ca(2+) uptake evoked by DMPP. Compounds 14, 15 and 17 inhibited the effects of DMPP by 30%. Compounds 3, 9 and tacrine blocked the DMPP signal by about 50%. Compounds 5 and 12 were the most potent blockers of DMPP-stimulated 45Ca(2+) entry (90%); the rest of the compounds inhibited the effects of DMPP by 70-80%. Compounds 1, 3, 4, 8, 10, 11, 13, 16, 17 and tacrine inhibited 45Ca(2+) uptake induced by K(+) about 20%. Compounds 6, 14 and 15 inhibited the K(+) effects by 10% or less. Compounds 7, 9, 12 and 18 blocked the K(+) signal by 30% and, finally, compounds 2 and 5 inhibited the K(+)-induced 45Ca(2+) entry by 50%. None of the new compounds was as effective as diltiazem (IC(50)=0.03 microM) in causing relaxation of the rat aorta precontracted with 35 mM K(+); the most potent was compound 7 (IC(50)=0.3 microM). Compounds 5, 6, 8, 9, 10 and 13 had IC(50)s around 10 microM and compounds 3, 4, 11 and 12 around 20 microM. Blockade of Ca(2+) entry through neuronal voltage-dependent Ca(2+) channels, without concomitant blockade of vascular Ca(2+) channels, suggests that some of these compounds might exhibit neuroprotectant effects but not undesirable hemodynamic effects.
de los Ríos
Cristóbal
C
Instituto Teófilo Hernando, Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de Madrid. C/Arzobispo Morcillo, 4, 28029, Madrid, Spain.
Marco
José L
JL
Carreiras
María D C
MD
Chinchón
P M
PM
García
Antonio G
AG
Villarroya
Mercedes
M
D000818:Animals; D001011:Aorta / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002417:Cattle; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D066298:In Vitro Techniques; D020128:Inhibitory Concentration 50; D015640:Ion Channel Gating / Q000187:drug effects*; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D015394:Molecular Structure; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013619:Tacrine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D013619:Tacrine; D004246:Dimethylphenylpiperazinium Iodide; D011188:Potassium; D002118:Calcium