Dexmedetomidine-induced contraction of isolated rat aorta is dependent on extracellular calcium concentration / 대한마취과학회지
Korean Journal of Anesthesiology
;
: 253-259, 2012.
Artículo
en Inglés
| WPRIM
| ID: wpr-187706
ABSTRACT
BACKGROUND:
Dexmedetomidine is a highly selective alpha2-adrenoceptor agonist that is widely used for sedation and analgesia during the perioperative period. Intravenous administration of dexmedetomidine induces transient hypertension due to vasoconstriction via the activation of the alpha2-adrenoceptor on vascular smooth muscle. The goal of this in vitro study is to investigate the calcium-dependent mechanism underlying dexmedetomidine-induced contraction of isolated endothelium-denuded rat aorta.METHODS:
Isolated endothelium-denuded rat thoracic aortic rings were suspended for isometric tension recording. Cumulative dexmedetomidine concentration-response curves were generated in the presence or absence of the following inhibitors alpha2-adrenoceptor inhibitor rauwolscine; voltage-operated calcium channel blocker verapamil (5 x 10(-7), 10(-6) and 5 x 10(-5) M); purported inositol 1,4,5-trisphosphate receptor blocker 2-aminoethoxydiphenylborate (5 x 10(-6), 10(-5) and 5 x 10(-5) M); phospholipase C inhibitor U-73122 (10(-6) and 3 x 10(-6) M); and store-operated calcium channel inhibitor gadolinium chloride hexahydrate (Gd3+; 5 x 10(-6) M). Dexmedetomidine concentration-response curves were also generated in low calcium concentrations (1 mM) and calcium-free Krebs solution.RESULTS:
Rauwolscine, verapamil, and 2-aminoethoxydiphenylborate attenuated dexmedetomidine-induced contraction in a concentration-dependent manner. Low calcium concentrations attenuated dexmedetomidine-induced contraction, and calcium-free Krebs solution nearly abolished dexmedetomidine-induced contraction. However, U-73122 and Gd3+ had no effect on dexmedetomidine-induced contraction.CONCLUSIONS:
Taken together, these results suggest that dexmedetomidine-induced contraction is primarily dependent on extracellular calcium concentrations that contribute to calcium influx via voltage-operated calcium channels of isolated rat aortic smooth muscle. Dexmedetomidine-induced contraction is mediated by alpha2-adrenoceptor stimulation. Dexmedetomidine-induced contraction appears to be partially mediated by calcium release from the sarcoplasmic reticulum.
Texto completo:
Disponible
Índice:
WPRIM (Pacífico Occidental)
Asunto principal:
Aorta
/
Fosfolipasas de Tipo C
/
Pirrolidinonas
/
Retículo Sarcoplasmático
/
Vasoconstricción
/
Yohimbina
/
Verapamilo
/
Canales de Calcio
/
Inositol 1,4,5-Trifosfato
/
Calcio
Límite:
Animales
Idioma:
Inglés
Revista:
Korean Journal of Anesthesiology
Año:
2012
Tipo del documento:
Artículo
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