Effects of waglerin-1 in mice hindlimb muscle during immobilization

BACKGROUND: Three isoforms of the neuronal acetylcholine receptors (AChRs) have been described in muscle epsilonAChRs, gammaAChRs and alpha7AChRs. The adult neuromuscular junctions are composed of epsilonAChRs. During immobilization, new AChRs with subunit compositions of gammaAChRs and alpha7AChRs appear in the perijunctional and extrajunctional area. This study evaluated the contribution of these isoforms to neurotransmission during immobilization, by using waglerin-1 which selectively blocks the epsilonAChRs. METHODS: Male mice (n = 20) were used and each group was divided into sham operated or immobilized. A leg was immobilized in mice for 14 days by pinning, after which nerve-evoked twitch tension was examined under anesthesia in tibialis muscle of both legs, with the contralateral leg serving as control. Neuromuscular transmission was monitored by using a peripheral nerve stimulator with the tibialis muscle and sciatic nerve. Electrical stimuli of 0.2 msec duration were applied to sciatic nerve 2 Hz for 2 sec every 30 sec. After administration of waglerin-1, the evoked twitch was recorded. The percent depression of T1 relative to baseline was transformed to probit scale to determine the effective dose of waglerin-1 for 5%, 50%, and 95% twitch depression. RESULTS: The twitch tension in the control group was higher than immobilized group, confirming the efficacy of immobilization. Waglerin-1 produced 99% twitch suppression on the control group. But on the immobilized group, waglerin-1 produced only 70% twitch suppression even at 37 pg. CONCLUSIONS: The functional role of epsilonAChRs in neurotransmission decreases during immobilization while that of gammaAChRs and alpha7AChRs increases.

The Effects of Temperature Monitoring Methods and Thermal Management Methods during Spinal Surgery / 대한마취과학회지

BACKGROUND: The precise measurement of body temperature during anesthesia is important to prevent hypothermia.The aim of this study was to compare the urinary bladder temperature to the esophageal, nasopharyngeal, rectal and skin temperatures, and to compare three heating methods during spine surgery. METHODS: Forty-two patients with ASA physical status I-II, who were scheduled to undergo spine surgery in the prone position, were included in this study.The patients were randomly divided into 4 groups:Group I was treated without any heating methods; group 2, with fluid-warmers; group 3, with forced air-warmers; and group 4, with a combination of both heating methods.After the induction of anesthesia, the esophageal, nasopharyngeal, rectal, urinary bladder and skin temperature was monitored every 15 minute for 3 hours.The urinary bladder temperature was compared to the esophageal, nasopharyngeal, rectal and skin temperatures. RESULTS: The urinary bladder temperature was found to be higher than the esophageal and the nasopharyngeal temperatures (P < 0.01).The urinary bladder temperature of group 3 was higher than that of group 1 at 180 minutes after induction of anesthesia (P < 0.05).The urinary bladder temperature of group 4 was higher than that of group 1 at 150 minutes (P < 0.05), as well as at 165 and 180 minutes (P < 0.05).The skin temperatures of groups 3 and 4 were higher than group 1 (P < 0.001). CONCLUSIONS: The urinary bladder temperature was higher than the esophageal temperature and correlated with the esophageal, nasopharyngeal and rectal temperatures.During spine surgery in the prone position, a forced air-warmer was found to be the most effective but a combination of all the methods tested was found to be even more effective.