Anesthesia and analgesia
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Anesthesia and analgesia · May 2013
Clinical TrialAssessment of pain during labor with pupillometry: a prospective observational study.
Pain intensity is usually self-rated by patients with a numeric rating scale (NRS) but this scale cannot be used for noncommunicating patients. In anesthetized patients, experimental noxious stimulus increases pupillary diameter (PD) and pupillary light reflex amplitude (PLRA), the difference between PD before and after light stimulation. Labor pain is an intense acute nonexperimental stimulus, effectively relieved by epidural analgesia. In this prospective observational study, we therefore describe the effects of labor pain and pain relief with epidural analgesia on PD and PLRA, determine their association with pain intensity and determine the ability of a single measurement of PD or PLRA to assess pain. ⋯ Changes in PD and PLRA brought about by a uterine contraction may be used as a tool to assess analgesia in noncommunicating patients.
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Anesthesia and analgesia · May 2013
The impact of hypothermia on emergence from isoflurane anesthesia in orexin neuron-ablated mice.
Orexin neurons regulate the sleep/wake cycle and are proposed to influence general anesthesia. In animal experiments, orexin neurons have been shown to drive emergence from general anesthesia. In human studies, however, the role of orexin neurons remains controversial, owing at least, in part, to the fact that orexin neurons are multifunctional. Orexin neurons regulate not only the sleep/wake cycle, but also body temperature. We hypothesized that orexin neurons do not directly regulate emergence from anesthesia, but instead affect emergence indirectly through thermoregulation because anesthesia-induced hypothermia can greatly influence emergence time. To test our hypothesis, we used simultaneous measurement of body temperature and locomotor activity. ⋯ The effect of orexin deficiency to impair thermoregulation during general anesthesia is of sufficient magnitude that body temperature must be appropriately controlled when studying the role of orexin neurons in emergence from anesthesia.
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Anesthesia and analgesia · May 2013
The antinociceptive effect of SNAP5114, a gamma-aminobutyric acid transporter-3 inhibitor, in rat experimental pain models.
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the mammalian central nervous system. GABAergic transmission has an important role in regulating nociception at the spinal dorsal horn. It is terminated by rapid uptake of the neurotransmitter from the synaptic cleft into neurons and glial cells, via specific GABA transporters (GATs). Among the 4 GATs, GAT-3 has the greatest expression in central nervous system regions closely associated with nociceptive transmission, including the spinal cord. In this study, we examined the antinociceptive effect of intrathecal administration of a selective GAT-3 inhibitor, SNAP5114, on acute, inflammatory, and neuropathic pain in experimental models. ⋯ These results suggest that SNAP5114 exerts antinociceptive effects by activating GABAA and GABAB receptors in the spinal cord. The GAT-3 inhibitor may prove useful in treatment of various painful conditions.