Linda S Barter

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BACKGROUND The spinal cord is an important site where volatile anesthetics decrease sensation and produce immobility. Beyond this knowledge, our understanding of a site of anesthetic action is limited. Previous evidence suggests that dorsal horn neurons with ascending projections may be more susceptible to depression by general anesthetics than local spinal(More)
BACKGROUND Anaesthetics blunt neuronal responses to noxious stimulation, including effects on electroencephalographic (EEG) responses. It is unclear how anaesthetics differ in their ability to modulate noxious stimulation-evoked EEG activation. We investigated the actions of propofol and halothane on EEG responses to noxious stimuli, including repetitive(More)
Isoflurane and halothane cause electroencephalographic (EEG) depression and neuronal depression in the reticular formation, a site critical to consciousness. We hypothesized that isoflurane, more than halothane, would depress EEG activation elicited by electrical microstimulation of the reticular formation. Rats were anesthetized with either halothane or(More)
Anesthesia is used widely in animal research, but there are diverse opinions regarding acceptable anesthetic depth. Excessive anesthesia is associated with increased morbidity and mortality. Traditionally, researchers have been taught that animal movement during surgical and experimental procedures indicates that the animal is 'underanesthetized.' Complex(More)
BACKGROUND Previous work demonstrated that isoflurane and halothane act on the spinal cord rather than on the brain to produce immobility in the face of noxious stimulation. These anesthetics share many effects on specific receptors, and thus do not test the broad applicability of the mediation of immobility by the cord. We sought to test such an(More)
Amphibians are commonly used in biomedical research, including studies of mechanisms of anaesthetic action. There is, however, little published work describing the kinetics of inhaled anaesthetic agents or the potency of isoflurane in amphibians. Ten Northern leopard frogs were exposed to a constant isoflurane concentration of 1.0%, 1.2% or 1.5% atm for 4(More)
We investigated whether propofol affected nociceptive behavior and fos-like immunoreactivity (FLI) in the lumbo-sacral spinal cord after intraplantar formalin injection in wild-type (WT) mice and in mutant mice harboring a point mutation of the gamma-aminobutyric acid type(A) receptor, which renders them resistant to propofol. Bolus injection of propofol(More)
BACKGROUND Evaluating the effects of sub-immobilizing anesthetic doses on movement will identify target neural circuits for investigation as sites of action for anesthetic-induced immobility. METHODS Eleven pithed Northern Leopard frogs received 0, 0.4, 0.8, and 1.2 times the 50% effective dose for production of immobility (ED(50)) of desflurane and a(More)
BACKGROUND The mechanism and site of action within the spinal cord by which volatile anesthetics produce immobility are not well understood. Little work has been done directly comparing anesthetic effects on neurons with specific functional characteristics that mediate transfer of nociceptive information within the spinal cord. METHODS Adult male rats(More)
Equilibration between delivered and effect site anesthetic partial pressure is slow in frogs. The use of less soluble agents or overpressure delivery may speed equilibration. Ten Northern leopard frogs were exposed to 3-4 constant concentrations of halothane, isoflurane or desflurane and their motor response to noxious electrical stimulation of the forelimb(More)