Sympatholytic and Minimum Anesthetic Concentration-sparing Responses are Preserved in Rats Rendered Tolerant to the Hypnotic and Analgesic Action of Dexmedetomidine, a Selective α2-adrenergic Agonist

Abstract

Tolerance does not develop for either the sympatholytic or MAC-sparing actions of dexmedetomidine, although it is present for the hypnotic response. The durable quality of the sympatholytic and MAC-sparing responses to dexmedetomidine after chronic treatment is explained by a comparatively larger receptor reserve than is needed for the hypnotic and analgesic responses, which are blunted by the same drug treatment regimen.

Heterozygous α 2A -adrenergic receptor mice unveil unique therapeutic benefits of partial agonists

“…1) or UK 14,304 (data not shown). These data provide definitive genetic evidence that sedation requires activation of greater than 50% of the ␣ 2A -AR population, consistent with the interpretation of previous studies in rats using covalent inactivation of amine-binding receptors (30) or regional antisense strategies (31) to incrementally diminish ␣ 2A -AR density. Our data affirm the formal possibility that differing fractional activation of receptors might evoke different receptor-mediated responses in different tissues, or in different neural pathways.…”

Addition of dexmedetomidine to lidocaine for intravenous regional anaesthesia 1

“…Dexmedetomidine produces sedation, analgesia and anxiolysis [8]. Reports of animal studies showed that dexmedetomidine reduced anaesthetic and analgesic requirements in rats [11] and dogs [12]. Previous clinical studies with dexmedetomidine have demonstrated reduced anaesthetic requirements.…”

Premedication With Dexmedetomidine Alone or Together With 0.5% Lidocaine for IVRA

“…Clonidine induces analgesia mainly through stimulation of a-2-adrenergic receptors in the dorsal horn of the spinal cord [16]. Dexmedetomidine produces sedation, analgesia, and anxiolysis [17,18], and previous animal studies indicate that dexmedetomidine reduces anesthetic and analgesic requirements in dogs [19] and rats [20]. In a previous study, Memis et al demonstrated that the addition of dexmedetomidine 0.5 mg/kg to lidocaine for IVRA led to significant reduction in sensory and motor blocks onset time compared with a control group.…”