Neuroscience letters
-
Neuroscience letters · Jan 2010
Synaptic plasticity in the substantia gelatinosa in a model of chronic neuropathic pain.
Chronic neuropathic pain (CNP) is common after peripheral nerve injuries (PNI), but is rather refractory to available anti-pain medication. Advances in neuropathic pain research have identified cellular and molecular cues triggering the onset of neuropathic pain, but the mechanisms responsible for maintenance of chronic pain states are largely unknown. Structural changes such as sprouting of injured A-fibres into the substantia gelatinosa of the dorsal horn in the spinal cord have been proposed to relate to neuropathic pain in partial PNI models. ⋯ Mechanical allodynia was measured up to 84 days after injury, after which synaptic changes were studied in the lumbar substantia gelatinosa. The numbers of larger sized synaptophysin-immunoreactive presynaptic boutons were found to be increased in the substantia gelatinosa ipsilateral to the nerve injury. From these data we conclude that structural synaptic changes within the substantia gelatinosa are present months after complete nerve injury and that this plasticity may be involved in maintaining neuropathic pain states.
-
Neuroscience letters · Jan 2010
Comparative StudyIsobolographic analysis of caramiphen and lidocaine on spinal anesthesia in rats.
The aims of the study were to evaluate the spinal anesthetic effect of caramiphen and also assess spinal anesthetic interactions of caramiphen with lidocaine. Lidocaine, a common local anesthetic, was used as control. Dose-dependent responses of intrathecal caramiphen on spinal anesthesia were compared with lidocaine in rats. ⋯ Co-administration of caramiphen with lidocaine produced an additive effect. Caramiphen and lidocaine are known to have local anesthetic effects as spinal anesthesia in rats. The spinal anesthetic effects of adding caramiphen to lidocaine are similar to the combinations of other anesthetics with lidocaine.
-
Neuroscience letters · Jan 2010
Blockade effects of BIBN4096BS on CGRP-induced inhibition on whole-cell K+ currents in spinal dorsal horn neuron of rats.
Calcitonin gene-related peptide (CGRP) plays an important role in the transmission and modulation of nociceptive information in the spinal cord. BIBN4096BS, a nonpeptide CGRP receptor antagonist, has been shown to be efficiency in clinical migraine treatment. ⋯ Furthermore, CGRP induced inhibition on whole-cell K(+) currents in cultured dorsal horn neurons of rats tested by whole-cell patch-clamp recording, and the effect was significantly blocked by BIBN4096BS. The results indicate that BIBN4096BS may produce antinociceptive effects at the spinal level in rats.
-
Neuroscience letters · Jan 2010
Olfactory dysfunction affects thresholds to trigeminal chemosensory sensations.
Next to olfaction and gustation, the trigeminal system represents a third chemosensory system. These senses are interconnected; a loss of olfactory function also leads to a reduced sensitivity in the trigeminal chemosensory system. However, most studies so far focused on comparing trigeminal sensitivity to suprathreshold stimuli; much less data is available with regard to trigeminal sensitivity in the perithreshold range. ⋯ Furthermore we could show that a betterment of the OD was accompanied by decreased thresholds. This was most evident in patients with postviral OD. In conclusion, factors such as age, olfactory status and etiology of olfactory disorder can affect responsiveness to perithreshold trigeminal chemosensory stimuli.
-
Neuroscience letters · Dec 2009
Effect of propofol on the levels of neurotransmitters in normal human brain: a magnetic resonance spectroscopy study.
Though widely used in anesthesia for many years, the mechanism underlying propofol anesthesia on human is not clear. Animal studies have already demonstrated that propofol functioned mainly by affecting neurotransmitters release. In our study, 10 healthy volunteers ranging from 20 to 40 years old were enrolled. ⋯ There was no obvious change in Cr levels in any statuses or brain regions. Our results indicate that propofol has an impact on the levels of neurotransmitters such as NAA, GLU, GABA and Cho in normal human brain. During propofol anesthesia, enhancement of inhibition or suppression of excitation may each play key roles in different brain regions.