Bupivacaine-induced Vasodilation Is Mediated by Decreased Calcium Sensitization in Isolated Endothelium-denuded Rat Aortas Precontracted with Phenylephrine
The Korean Journal of Pain
;
: 229-238, 2014.
Article
in English
| WPRIM
| ID: wpr-221026
ABSTRACT
BACKGROUND:
A toxic dose of bupivacaine produces vasodilation in isolated aortas. The goal of this in vitro study was to investigate the cellular mechanism associated with bupivacaine-induced vasodilation in isolated endotheliumdenuded rat aortas precontracted with phenylephrine.METHODS:
Isolated endothelium-denuded rat aortas were suspended for isometric tension recordings. The effects of nifedipine, verapamil, iberiotoxin, 4-aminopyridine, barium chloride, and glibenclamide on bupivacaine concentration-response curves were assessed in endothelium-denuded aortas precontracted with phenylephrine. The effect of phenylephrine and KCl used for precontraction on bupivacaine-induced concentration-response curves was assessed. The effects of verapamil on phenylephrine concentration-response curves were assessed. The effects of bupivacaine on the intracellular calcium concentration ([Ca2+]i) and tension in aortas precontracted with phenylephrine were measured simultaneously with the acetoxymethyl ester of a fura-2-loaded aortic strip.RESULTS:
Pretreatment with potassium channel inhibitors had no effect on bupivacaine-induced relaxation in the endothelium-denuded aortas precontracted with phenylephrine, whereas verapamil or nifedipine attenuated bupivacaine-induced relaxation. The magnitude of the bupivacaine-induced relaxation was enhanced in the 100 mM KCl-induced precontracted aortas compared with the phenylephrine-induced precontracted aortas. Verapamil attenuated the phenylephrine-induced contraction. The magnitude of the bupivacaine-induced relaxation was higher than that of the bupivacaine-induced [Ca2+]i decrease in the aortas precontracted with phenylephrine.CONCLUSIONS:
Taken together, these results suggest that toxic-dose bupivacaine-induced vasodilation appears to be mediated by decreased calcium sensitization in endothelium-denuded aortas precontracted with phenylephrine. In addition, potassium channel inhibitors had no effect on bupivacaine-induced relaxation. Toxic-dose bupivacaine- induced vasodilation may be partially associated with the inhibitory effect of voltage-operated calcium channels.
Full text:
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Index:
WPRIM (Western Pacific)
Main subject:
Aorta
/
Phenylephrine
/
Relaxation
/
Barium
/
Vasodilation
/
Bupivacaine
/
Nifedipine
/
Verapamil
/
Calcium Channels
/
Potassium Channels
Limits:
Animals
Language:
English
Journal:
The Korean Journal of Pain
Year:
2014
Type:
Article
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