Anesthesiology
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Comparative Study
Eyes in the needle: novel epidural needle with embedded high-frequency ultrasound transducer--epidural access in porcine model.
Epidural needle insertion is usually a blind technique where the rate of adverse events depends on the experience of the operator. A novel ultrasound method to guide epidural catheter insertion is described. ⋯ This is the first study to introduce a new ultrasound probe embedded in a standard epidural needle. It is anticipated that this technique could reduce failed epidural blocks and complications caused by dural puncture.
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Comparative Study
The quaternary lidocaine derivative, QX-314, exerts biphasic effects on transient receptor potential vanilloid subtype 1 channels in vitro.
Transient receptor potential vanilloid subfamily member 1 (TRPV1) channels are important integrators of noxious stimuli with pronounced expression in nociceptive neurons. The experimental local anesthetic, QX-314, a quaternary (i.e., permanently charged) lidocaine derivative, recently has been shown to interact with and permeate these channels to produce nociceptive and sensory blockade in animals in vivo. However, little is known about the specific interactions between QX-314 and TRPV1 channels. Thus, the authors examined the mechanistic basis by which QX-314 acts on TRPV1 channels. ⋯ The results of this study show that the quaternary lidocaine derivative QX-314 exerts biphasic effects on TRPV1 channels, inhibiting capsaicin-evoked TRPV1 currents at lower (micromolar) concentrations and activating TRPV1 channels at higher (millimolar) concentrations. These findings provide novel insights into the interactions between QX-314 and TRPV1 and may provide an explanation for the irritant properties of intrathecal QX-314 in mice in vivo.
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The possibility of restoring sevoflurane postconditioning (sevo-postC) cardioprotection in diabetic animals is uncertain. We hypothesized that attenuation of myocardial injury by sevo-postC might be hindered by inhibition of signal transducer and activator of transcription (STAT) 3-regulated activity of phosphatidylinositol 3-kinase (PI3K) in diabetic animals. To determine whether postC cardioprotection can be restored by normoglycemia, we treated rats with insulin. ⋯ The effective reduction in infarct size and apoptosis in the nondiabetic rat heart by postC was completely abrogated in diabetic rats. This inhibition is not relieved by insulin-induced normoglycemia. The PI3K pathway and mitochondrial adenosine triphosphate-dependent potassium channel activation are involved in the mechanism of postC. In diabetic rats, STAT3 activation was strongly reduced, as was postC cardioprotection, suggesting that the inability of insulin to restore postC may be attributed to diabetes-induced STAT3-mediated inhibition of PI3K signaling.
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There is poor experimental evidence concerning the effects of anesthetic doses of the noncompetitive N-methyl-D-aspartate receptor antagonist ketamine on rodents' memory abilities. The current study was designed (1) to investigate the consequences of posttraining administration of anesthetic ketamine (100 mg/kg intraperitoneally) on rats' recognition memory and (2) to evaluate the ability of the nitric oxide synthase inhibitor N-nitro-L-arginine methylester (L-NAME; 1, 3, and 10 mg/kg intraperitoneally) to counteract the expected behavioral deficits produced by anesthetic ketamine. Finally, in an attempt to clarify if the expected memory impairments produced by anesthetic ketamine were related to the anesthesia, we also tested the effects of a subanesthetic dose of it (3 mg/kg intraperitoneally) on rats' recognition memory. ⋯ The current results indicate that anesthetic ketamine impaired rats' posttraining memory components (storage and/or retrieval of information) and that a nitric oxide component modulates its behavioral effects.
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Comparative Study
Spinal anesthesia in infant rats: development of a model and assessment of neurologic outcomes.
Previous studies in infant rats and case-control studies of human infants undergoing surgery have raised concerns about potential neurodevelopmental toxicities of general anesthesia. Spinal anesthesia is an alternative to general anesthesia for some infant surgeries. To test for potential toxicity, a spinal anesthesia model in infant rats was developed. ⋯ Spinal anesthesia is technically feasible in infant rats and appears benign in terms of neuroapoptotic and neuromotor sequelae.