title: Efficacy of intrathecal esmolol on heat-evoked responses in a postoperative pain model.
abstract: Perioperative tachycardia and hypertension are often treated with esmolol, a short-acting β1-adrenoceptor antagonist. Besides its cardiac effect, esmolol is reported to exert antinociceptive effects. This study examined the efficacy of intrathecal (IT) esmolol on pain responses in a postoperative pain model. Male Sprague-Dawley rats (250-300 g) were anesthetized with sevoflurane and an IT catheter was implanted. Six days after catheter implantation, a postoperative pain model was established by plantar incision under sevoflurane anesthesia. Withdrawal latencies were assessed by applying a focused radiant heat source before plantar incision; 1 day after the incision (before esmolol administration); and 5, 10, and 15 minutes after bolus administration of IT esmolol. Plantar incision produced hypersensitivity in the postoperative pain model expressed as decreased withdrawal latency to heat stimulation (before incision: 13.9 ± 0.29 seconds and 1 day after incision: 6.3 ± 0.26 seconds). These decreased latencies caused by incision were significantly increased by esmolol administration (40 μg, 80 μg) at 5 minutes (10.7 ± 1.16 seconds, 10.5 ± 1.16 seconds). No postoperative antinociceptive effects of esmolol were observed at 10 or 15 minutes. IT administration of esmolol produced antinociceptive effects of short duration in a rat postoperative pain model. These results suggest that IT esmolol could offer a new strategy for managing perioperative pain, although an alternative approach is necessary to lengthen the duration of the analgesia.
authors: 1Division of Dento-oral Anesthesiology, Tohoku University Graduate School of Dentistry, Sendai, Japan 2Department of Anesthesiology, Omiya General Hospital, Saitama, Japan 3Department of Anesthesiology, Jikei University School of Medicine, Tokyo, Japan.
authors: Hitomi
authors: H
authors: Ono
authors: Norimasa
authors: N
authors: Ohtani
authors: Atsuko
authors: A
authors: Matoba
authors: Kanta
authors: K
authors: Kido
authors: Yutaka
authors: Y
authors: Yasui
authors: Eiji
authors: E
authors: Masaki
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004195:Disease Models, Animal; D006358:Hot Temperature; D007278:Injections, Spinal; D008297:Male; D010149:Postoperative Pain / Q000188:drug therapy*; D011412:Propanolamines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D011412:Propanolamines; C036604:esmolol