[Mechanisms of pethidine-induced vasodilatation].
To investigate the vasodilating effects of pethidine, particularly in association with intracellular calcium.



Aorta rings of Sprague-Dawley rats, with or without endothelium, were prepared in organ bath to measure the vascular tone. Pre-contractions by KCl (80 mmol/L) and phenylephrine (PhE) (10(-6)mol/L) were induced.



Pethidine did not alter the resting tension of aorta rings, but produced dose-dependent relaxation in KCl and PhE pre-treated aorta rings with or without endothelium. Pethidine did not change the caffeine-stimulated contraction, and still had similar inhibition in KCl pre-contracted aorta rings after pretreatment with ruthenium red. Pethidine decreased the contractile responses induced by PhE in Ca(2+)-free solution or by adding calcium into Ca(2+)-free solution.



Pethidine could produce an endothelium-independent vasodilatation in KCl and PhE pre-contracted aorta rings, which is related to inhibition of Ca(2+)entry and IP3-sensitive Ca(2+) release in vascular smooth muscle.
Zhang
Xiong
X
Department of Physiology, College of Medicine, Zhejiang University  Hangzhou 310031, China.
Chai
Ling-ying
LY
Tong
Xiao-mei
XM
Lu
Yuan
Y
Xia
Qiang
Q
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D008297:Male; D008614:Meperidine / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D002110:Caffeine; D011189:Potassium Chloride; D008614:Meperidine; D002118:Calcium