Neuroscience letters
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Neuroscience letters · Dec 2008
Chronic administration of antipsychotics impede behavioral recovery after experimental traumatic brain injury.
Antipsychotics are often administered to traumatic brain injured (TBI) patients as a means of controlling agitation, albeit the rehabilitative consequences of this intervention are not well known. Hence, the goal of this study was to evaluate the effects of risperidone (RISP) and haloperidol (HAL) on behavioral outcome after experimental TBI. Anesthetized rats received either a cortical impact or sham injury and then were randomly assigned to five TBI (RISP 0.045mg/kg, RISP 0.45mg/kg, RISP 4.5mg/kg, HAL 0.5mg/kg and VEHicle 1mL/kg) and three Sham (RISP 4.5mg/kg, HAL 0.5mg/kg and VEH 1mL/kg) groups. ⋯ Behavior was assessed with established motor (beam-balance/walk) and cognitive (spatial learning/memory in a water maze) tasks on post-operative days 1-5 and 14-19, respectively. RISP and HAL delayed motor recovery, impaired the acquisition of spatial learning, and slowed swim speed relative to VEH in both TBI and sham groups. These data indicate that chronic administration of RISP and HAL impede behavioral recovery after TBI and impair performance in uninjured controls.
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Neuroscience letters · Dec 2008
Cough reflex responses during pulmonary C-fibre receptor activation in anesthetized rabbits.
We investigated the changes induced by pulmonary C-fibre receptor activation in the cough reflex evoked by mechanical stimulation of the tracheobronchial tree in pentobarbitone anesthetized, spontaneously breathing rabbits. Phrenic nerve and abdominal muscle activities were monitored along with tracheal and arterial blood pressures. ⋯ At variance with previous findings in cats and dogs, the results show that tracheobronchial cough is not significantly reduced in the rabbit during PBG-induced chemoreflex. This study is the first to provide evidence supporting the hypothesis that the time components of the cough motor pattern are, to some extent, dependent upon the timing characteristics of the ongoing respiratory activity and suggests a novel mechanism leading to cough depression.
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Neuroscience letters · Dec 2008
Time course of caspase activation in selectively vulnerable brain areas following global cerebral ischemia due to cardiac arrest in rats.
This study evaluated the time course of caspase activation in selectively vulnerable brain areas (hippocampus, nucleus reticularis thalami (NRT), cortex and striatum) following cardiopulmonary resuscitation (CPR) after global cerebral ischemia due to cardiac arrest (CA) in rats. Caspases are well known to play a crucial role in the apoptotic cascade and inflammatory syndromes and, therefore, represent potential therapeutic postischemic targets. Given the delayed neurodegeneration following CA, it is highly important to study the time course of caspase activation in regard to therapeutic interventions after CA. ⋯ At 7d, the TUNEL-positive neuron counts in the hippocampal CA-1 sector correlated strongly with caspase activation. In conclusion, general caspase and caspase-3 activity after 6 min of CA and the delayed occurrence of TUNEL-positive neurons strongly indicate that neuronal degeneration after CA is at least strongly associated with apoptosis. Therefore, postischemic antiapoptotic interventions might offer potential future therapeutic opportunities global cerebral ischemia due to CA.
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Neuroscience letters · Dec 2008
Mismatch negativity to the patient's own name in chronic disorders of consciousness.
Previous studies implicated potential value of mismatch negativity (MMN) in predicting recovery of consciousness in patients with disorders of consciousness (DOC). We have adopted a novel MMN evoked by subject's own name (SON), a self-referential stimulus thought to be powerful in evoking residual brain activity, and examined the correlation between the MMN and recovery of consciousness in patients with chronic (>1 month) DOC. Twelve patients and 12 age-matched healthy controls were investigated. ⋯ Critically, the presence of SON-MMN was significantly correlated with recovery of consciousness. While four of the five patients (three VS and two coma) showing SON-MMN changed to MCS 3 months later, the rest of the patients (three VS and two coma) without SON-MMN failed to show any clinical improvement. Our study thus illustrates that the subject's own name is effective in evoking MMN in patients with DOC, and that SON-MMN has potential prognostic values in predicting recovery of consciousness.
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Neuroscience letters · Dec 2008
Anxiety-like behaviour is attenuated by gabapentin, morphine and diazepam in a rodent model of HIV anti-retroviral-associated neuropathic pain.
Neuropathic pain is commonly associated with affective disorders such as anxiety and depression. We have previously characterised a rodent model of HIV, anti-retroviral-associated neuropathy in which rats develop hypersensitivity to a punctate mechanical stimulus and display anxiety-like behaviour in the open field paradigm. ⋯ The effect of gabapentin and morphine did not differ significantly from diazepam (1 mg/kg, i.p.). This study highlights the potential use of this rodent model and behavioural paradigm in the validation of the affective component of novel analgesic pharmacological targets and elucidation of underlying pathophysiological mechanisms.