Possible calcium channel modulating activity of iloprost in rabbit isolated vascular segments.
1. Iloprost produced a concentration-dependent decrease in the contractile responses to K+ and NA in CoeA and SMA strips without altering the responses in RA, MPA, CaA and ThA. 2. Nifedipine and verapamil also inhibited the contractile responses to NA and K+ in CoeA and SMA rings in a concentration dependent manner. 3. Removal of endothelium did not alter the inhibitory effects of iloprost and Ca2+ channel blockers in the investigated arterial segments. 4. In Ca2+ free and high K+ medium both iloprost and Ca2+ channel blockers potentially inhibited the contractile effect of external Ca2+. 5. Iloprost at lowest concentration which is not influence the contractile response of K+ can potentiate the inhibitory effect of nifedipine in CoeA and SMA rings without altering its inhibitory effect on NA responses. 6. These results suggest that iloprost may modulate Ca2+ entry into the cell probably by acting through the potential-operated Ca2+ channels in CoeA and SMA. These results also indicate that Ca2+ channels are heterogenously functioned in various vascular segments of rabbit.
Demĭrel
E
E
Department of Pharmacology, Faculty of Medicine, University of Ankara, Turkey.
Türker
R K
RK
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D011464:Epoprostenol / Q000494:pharmacology*; D005260:Female; D016285:Iloprost; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits
D015220:Calcium Channels; D011189:Potassium Chloride; D011464:Epoprostenol; D009543:Nifedipine; D016285:Iloprost; D009638:Norepinephrine