Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2010
The relationship between functional sciatic nerve block duration and the rate of release of lidocaine from a controlled-release matrix.
Nerve blocks of long duration are often desirable in perioperative and postoperative situations. The relationship between the duration of such blocks and the rate at which a local anesthetic is released is important to know for developing a localized drug delivery system that will optimize block duration. ⋯ Increasing initial lidocaine content proportionately increased the duration of functional sciatic nerve block. However, decreasing the release rate per se does not give a proportional increase in block duration. Instead, there seems to be an optimal, intermediate release rate for achieving the maximum duration of block.
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Anesthesia and analgesia · Jul 2010
Resiniferatoxin combined with antidepressants preferentially prolongs sensory/nociceptive block in rat sciatic nerve.
Current techniques of peripheral nerve block have major limitations, including lack of differentiation between motor and sensory fibers and potential toxicity of local anesthetics. Recent studies have suggested that a nociceptive-selective nerve block can be achieved via a transient receptor potential vanilloid type 1 activator (capsaicin) along with local anesthetics. We hypothesized that the combination of potent transient receptor potential vanilloid type 1 agonist resiniferatoxin (RTX) and selected antidepressants (amitriptyline, doxepin, and fluoxetine, also potent sodium channel blockers) would produce prolonged and predominantly sensory nerve block. ⋯ The combined application of RTX and antidepressants produced a markedly prolonged nociceptive peripheral nerve block in rat sciatic nerves compared with either agent alone. However, the 2-drug regimen also elicited prolonged blockade of the motor function, although disproportionately less compared with the nociceptive modality, suggesting the existence of nontransient receptor potential vanilloid type 1-mediated mechanisms. The mechanisms through which RTX affects nociceptive signal transduction/transmission have yet to be fully elucidated.
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Anesthesia and analgesia · Jul 2010
Activation of central opioid receptors induces cardioprotection against ischemia-reperfusion injury.
Small doses of intrathecal morphine provide cardioprotection similar to that conferred by IV morphine and ischemic preconditioning (IPC). We investigated the relative role of central versus peripheral opioid receptors in intrathecal morphine preconditioning (ITMPC). ⋯ Intrathecally administered morphine can produce cardioprotective effects via the activation of central opioid receptors, without the apparent involvement of peripheral opioid receptors.