ABSTRACT
Objective To investigate the effects of propofol on mesenteric artery in SD rats and to observe whether the effect of propofol on the mesenteric artery relaxation is related to the gap. Methods Pressure myograph was used to examine the effect of 18β-GA and 2-APB on the relaxation induced by propofol 1×10 -7 ,3×10 -7 ,1×10 -6 ,3×10 -6 ,1 ×10 -5 ,3 ×10 -5 ,1 ×10 -4 and 3 ×10 -4 mol/L in acutely separated mesenteric arterioles of SD rat.Results The diameter of mesenteric arteri-oles were increased from (208.6±13.4)to (213.5±13.6),(21 9.7±13.2),(226.4±12.5),(234.9 ±12.3),(245.5±13.0),(267.4±1 5.2),(336.2±18.3)and (385.9 ±14.2)μm after application of 1×10 -7 ,3×10 -7 ,1 × 10 -6 ,3 × 10 -6 ,1 × 10 -5 ,3 × 10 -5 ,1 × 10 -4 and 3 × 10 -4 mol/L propofol,re-spectively.Propofol induced dilation of the rat mesenteric arterioles in a concentration-dependent man-ner (P < 0.01 ).After pretreatment with 18β-GA and 2-APB,1 × 10 -4 mol/L propofol induced dilation was absolutely decreased (P <0.01).Conclusion These results suggest that propofol relaxes mesenteric arterioles via gap junction.
ABSTRACT
Objective To investigate the effects and mechanisms of hypoxia on the contraction of mesen-teric arteries induced by phenylephrine (PE) in guinea pig. Methods Pressure myograph system was used to study the effects of 20, 40 and 60 min hypoxia (mixed with 95% CO2 and 5% O2) on the constriction induced by PE in acutely separated mesenteric artery (300 ~ 400 μm) of guinea pig. Results PE (0.1 ~ 100 μmol/L) caused the contractions of the mesenteric arteries in guinea pig in a concentration-dependent way . Hypoxia de creased the pH value of perfusion fluid from 7.4 to 6.3. Hypoxia significantly inhibited PE-induced vasocon-striction, and the inhibition was hard to recover after reoxygenation. Hypoxia inhibited PE-induced vasoconstric-tion in a time-dependent way , with the inhibition rate reduced in the sequence of inhibition duration of 60 , 40 and 20 min. When its value was decreased to 6.3 , the perfusion fluid even inhibited PE-induced vasoconstric tion. Conclusion Hypoxia can inhibit PE-induced vasoconstriction in the mesenteric arteries of guinea pig in a time-dependent way. The mechanism may have something to do with the change of pH.