Abstract
This study was performed to examine the changes in local cortical blood flow (CoBF) after simultaneous administration of an alpha2 adrenergic agonist (dexmedetomidine) and a calcium channel antagonist (verapamil) to urethane-anaesthetized rats. Dexmedetomidine (100 μg · kg−1) given intraperitoneally alone resulted in decreases in mean arterial blood pressure (MABP) (F[27,140] = 3.43;P < 0.01) and CoBF (F[27,140] = 4.22; P < 0.01), whereas the heart rate (HR) was increased (F[27.140] = 2.33; P< 0.01). Verapamil (2.5 mg· kg−1) given subcutaneously reduced the MABP (F[27,140]) =3.41; P < 0.01), but the HR and CoBF were not changed. Combined administration of the drugs decreased MA PB (F[27,140]) = 5.37; P < 0.01), with no changes in CoBF and HR. The present data indicate that the calcium channel antagonist verapamil did not potentiate the haemodynamic effects of dexmédétomidine in rats, but rather attenuated the effect of dexmédétomidine on CoBF. This favourable interaction suggests a potential therapeutic role of these agents in maintaining cardiovascular stability during surgical interventions.
Résumé
Cette étude a été réalisée pour évaluer les changements du débit sanguin cortical (DSCo) après l’administration simultanée d’un agoniste alpha2 adrénergique (dexmédétomidine) et d’un inhibiteur calcique (vérapamil) à des rat anesthésiés à l’uréthane. La dexmédétomidine seule (100 μg · kg−1) administrée par la voie péritonéale provoque une baisse de la tension artérielle moyenne (TAM) (F[27,140] = 3,43; P < 0,01) et du DSCo (F[27,140] = 4,22; P < 0,01), pendant que la fréquence cardiaque (Fc) augmente F[27,140] = 2,33; P < 0,01). Le vérapamil (2,5 kg−1) souscutané provoque une baisse de la TAM (F[27,140] = 3,41; P < 0,01). L’administration combinée des deux médicaments diminue la TAM (F[27,140] = 5,37; P < 0,01), sans modifier le DSCo et la Fc. Ces données indiquent que l’inhibiteur calcique vérapamil n’augmente pas les effets hémodynamiques de la dexmédétomidine chez le rat, mais atténue l’effet de la dexmédétomidine sur le DSCo. Cette enteraction favorable suggère la possibilité d’une l’application thérapeutique de ces agents pour le maintien de la stabilité cardiovasculaire pendant la chirurgie.
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Bari, F., Horvāth, G. & Benedek, G. Dexmedetomidine-induced decrease in cerebral blood flow is attenuated by verapamil in rats: a laser Doppler study. Can J Anaesth 40, 748–754 (1993). https://doi.org/10.1007/BF03009771
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DOI: https://doi.org/10.1007/BF03009771