Effect of chronic lithium administration on endothelium-dependent relaxation in rat aorta.
1. The effects of chronic lithium administration on the relaxant responses of rat thoracic aortic rings in the presence of indomethacin (a cyclo-oxygenase inhibitor) and/or NG-nitro-L-arginine (L-NOARG; a nitric oxide synthase inhibitor) to acetylcholine (ACh) or sodium nitroprusside were investigated in the present study. 2. Acetylcholine produced a concentration-dependent relaxation in vessels precontracted by phenylephrine (PE), while in lithium-treated rats the maximal relaxation was significantly increased. 3. Indomethacin (20 mumol/L) significantly potentiated the ACh-induced relaxation in lithium-treated and control rats. 4. NG-Nitro-L-arginine (1 mumol/L) decreased the ACh-induced relaxation in both control and lithium-treated rats. In contrast, indomethacin (20 mumol/L) reversed the inhibitory effect of L-NOARG. 5. Sodium nitroprusside produced similar concentration-dependent relaxations of vessels from both control and lithium-treated rats, which was not affected by indomethacin. In endothelium-denuded rings, indomethacin (20 mumol/L) caused a rightward shift in the concentration-contraction curve to PE. 6. These data support evidence for a possible increase in endothelium-dependent relaxation induced by ACh during long-term administration of lithium in rat aortic rings.
Dehpour
A R
AR
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Iran. ardeh@nrcgeb.ac.ir
Aghadadashi
H
H
Ghafourifar
P
P
Roushanzamir
F
F
Ghahremani
M H
MH
Meysamee
F
F
Rassaee
N
N
Koucharian
A
A
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D018692:Antimanic Agents / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D018021:Lithium Chloride / Q000494:pharmacology*; D008297:Male; D019335:Nitroarginine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D018692:Antimanic Agents; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D019335:Nitroarginine; D018021:Lithium Chloride; D000109:Acetylcholine; D007213:Indomethacin