Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jul 2005
Comparative StudyComparison of the effects of isoflurane and sevoflurane on protein tyrosine phosphorylation-mediated vascular contraction.
Isoflurane induces greater effects on vasodilation and decreasing blood pressure than sevoflurane. Tyrosine kinase-catalyzed protein tyrosine phosphorylation plays an important role in regulating vascular smooth muscle contraction. The aim of the present study was to compare the effects of isoflurane and sevoflurane on tyrosine phosphorylation-mediated vascular constriction, by assessing the degree of sodium orthovanadate (Na(3)VO(4), tyrosine phosphatase inhibitor)-induced contraction and protein tyrosine phosphorylation of rat aortic smooth muscle. ⋯ The results of the present study demonstrate that isoflurane exhibits a greater degree of inhibition on the Na(3)VO(4)-stimulated contraction and protein tyrosine phosphorylation of rat aortic smooth muscle compared with sevoflurane. These findings suggest that isoflurane depresses the protein tyrosine phosphorylation-mediated contraction of vascular smooth muscle to a greater degree than sevoflurane.
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Acta Anaesthesiol Scand · Jul 2005
Effects of phosphodiesterase-III inhibitors on sevoflurane-induced impairment of rat diaphragmatic function.
Volatile anesthetics are known to cause diaphragmatic dysfunction using a whole body model. The first aim of the current study was to compare the impairing effect of halothane and sevoflurane on diaphragmatic contractile functions under unfatigued and fatigued conditions. The second purpose was to determine whether phosphodiesterase-III inhibitors can attenuate sevoflurane-potentiated reduction of contractility after fatigue. ⋯ Our findings suggest that sevoflurane has a greater decreasing effect on diaphragmatic contractility after fatigue than halothane, and that the clinical dose of olprinone surmounts the disadvantage of sevoflurane in various conditions where diaphragmatic fatigue is predisposed.
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Nociceptin is the endogenous agonist of the opioid receptor-like (ORL) 1 receptor (NOP), and both nociceptin and NOP are widely expressed in the brain and spinal cord, which are target organs of general anaesthetics. As nociceptin has been reported to be involved in modulating pain mechanisms and stress responses, it is possible that the activity of the nociceptin system affects the anaesthetic potency of general anaesthetics. To address this possibility, we investigated the minimum alveolar concentrations (MACs) of various volatile anaesthetics in nociceptin receptor knockout mice (NOP-/-) and wild-type mice (NOP+/+). ⋯ MACs in NOP-/- mice did not significantly differ from those in NOP+/+ mice for halothane, isoflurane and sevoflurane. This result suggests that the nociceptin system does not affect the anaesthetic potency of volatile anaesthetics.
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Acta Anaesthesiol Scand · Jul 2005
Safety of mixture of morphine with ketamine for postoperative patient-controlled analgesia: an audit with 1026 patients.
Adding ketamine to morphine for patient-controlled analgesia (PCA) may be useful. However, data on this drug combination have been collected on small sample sizes. In order to evaluate the safety of the combination morphine- ketamine, we conducted a prospective study on a large patient population. ⋯ Patient-controlled analgesia with morphine and ketamine is safe. It produces side-effects which, however, are infrequently a reason for discontinuing the regimen. It is also associated with low pain scores and high patient satisfaction.