Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2008
Comparative StudyMolecular actions of propofol on human 5-HT3A receptors: enhancement as well as inhibition by closely related phenol derivatives.
5-Hydroxytryptamine type 3 (5-HT3) receptors are excitatory ligand-gated ion channels which are involved in postoperative nausea and vomiting. They are depressed by the anesthetic propofol, which, in contrast, enhances the activity of inhibitory ligand-gated ion channels such as gamma-aminobutyric acid type A receptors and glycine receptors. To investigate the molecular mechanisms responsible for these contrasting actions, we examined the kinetics of the action of propofol and its lesser hydrophobic derivatives 2-isopropylphenol and phenol on human 5-HT3A receptors. ⋯ At least two separate inhibitory actions on 5-HT3A receptors could be identified for propofol, whereas the enhancing action seen for the two related smaller phenol derivatives could no longer be detected. 5-HT-dependent and 5-HT-independent interactions could be distinguished for all three drugs. Propofol was less potent than expected from its hydrophobic properties. Underlying mechanisms appear to involve the phenolic hydroxyl group, hydrophobic interactions, and steric restrictions.
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During craniosynostosis repair, massive blood loss, consumption and dilution of clotting factors often result in coagulopathy, for which cryoprecipitate, fresh frozen plasma (FFP), and platelets are recommended for treatment. However, cryoprecipitate is not available in most European countries, and the efficacy of FFP in correcting fibrinogen deficiency is limited. We report our experience with human fibrinogen concentrate (Hemocomplettan) used to improve impaired fibrinogen polymerization in children. ⋯ Administration of fibrinogen concentrate effectively improves fibrinogen polymerization and total clot strength, which were the main underlying problems of dilutional coagulopathy in children undergoing craniosynostosis surgery.
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Anesthesia and analgesia · Mar 2008
Intrathecally injected morphine inhibits inflammatory paw edema: the involvement of nitric oxide and cyclic-guanosine monophosphate.
Morphine can inhibit inflammatory edema in experimental animals. The mechanisms and sites by which opioids exert this effect are still under debate. Since the spinal level is a site for modulation of the neurogenic component of inflammation, we investigated the effect of intrathecal (i.t.) administration of morphine, and the involvement of spinal nitric oxide (NO)/cyclic-guanosine monophosphate-GMP pathway in carrageenan (CG)-induced paw edema. ⋯ These results support the idea that morphine can act on opioid receptors at the spinal level to produce antiedematogenic, and that the NO/cGMP pathway seems to be an important mediator in this effect.
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Anesthesia and analgesia · Mar 2008
The effect of limited rewarming and postoperative hypothermia on cognitive function in a rat cardiopulmonary bypass model.
Clinical studies have failed to demonstrate significant benefits of hypothermia for the prevention of postoperative cognitive dysfunction (POCD) after cardiopulmonary bypass (CPB). One explanation for this might be that potentially injurious cerebral hyperthermia occurs during rewarming at the end of CPB, off-setting the protective benefits of hypothermia. In this study, we investigated the relative influence of CPB temperature, rewarming strategies, and postoperative temperature in a rat CPB model. ⋯ The combination of hypothermic (32 degrees C) CPB coupled with limited rewarming and prolonged postoperative hypothermia (35 degrees C) decreased POCD after CPB in rats.