Epinephrine, phenylephrine, and methoxamine induce infiltrative anesthesia via alpha1-adrenoceptors in rats.

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Shieh JP, Chu CC, Wang JJ, Lin MT

Epinephrine, phenylephrine, and methoxamine induce infiltrative anesthesia via alpha1-adrenoceptors in rats.

Acta Pharmacol Sin. 2009 Sep;30(9):1227-36. doi: 10.1038/aps.2009.129.

PubMed ID

19730427 [ View in PubMed

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Abstract

AIM: To assess whether epinephrine, phenylephrine, and methoxamine act via certain subtypes of adrenoceptors to exert their local anesthetic activity. METHODS: We investigated cutaneous anesthesia from adrenoceptor agonists and/or antagonists in conscious, unanesthetized Sprague-Dawley male rats (weight 200-250 g). Cutaneous anesthesia was evidenced by a block of the cutaneous trunci muscle reflex, which is characterized by reflex movement of the skin over the back produced by twitches of lateral thoracispinal muscles in response to local dorsal cutaneous noxious pinprick. RESULTS: Local infiltration of epinephrine, L-phenylephrine, or methoxamine alone induces cutaneous anesthesia in rats in a dose-dependent way. Epinephrine is found to be 19 and 29 times more potent than those of methoxamine and L-phenylephrine, respectively. The cutaneous anesthesia induced by epinephrine, phenylephrine, or methoxamine can be significantly reduced by alpha(1)-adrenoceptor antagonists (eg, prazosin), alpha1, alpha2-adrenoceptor antagonist, alpha(1A)-adrenoceptor antagonist (eg, 5-methylurapdil), alpha(1B)-adrenoceptor antagonist (eg, chloroethylclonidine), or alpha(1D)-adrenoceptor antagonist (eg, BMY7873). CONCLUSION: Our results indicate that epinephrine, phenylephrine and methoxamine all act mainly via mixed subtypes of alpha(1)-adrenoceptors to induce cutaneous anesthesia in the rat.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Epinephrine	Alpha-1B adrenergic receptor	Protein	Humans	Yes	Agonist	Details
Epinephrine	Alpha-1D adrenergic receptor	Protein	Humans	Unknown	Antagonist	Details