Progress in neuro-psychopharmacology & biological psychiatry
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Prog. Neuropsychopharmacol. Biol. Psychiatry · May 2005
Comparative StudyA comparative study with two types of elevated plus-maze (transparent vs. opaque walls) on the anxiolytic effects of midazolam, one-trial tolerance and fear-induced analgesia.
The phenomenon known as one-trial tolerance (OTT) to the anxiolytic effects of benzodiazepines observed in rats submitted to the elevated plus-maze test (EPM) is considered to be due to the emergence of phobic states across the test/retest sessions. Antinociception is a usual component of the defense reaction. Until now, no study has examined antinociception and OTT together in freely behaving rats in the EPM. ⋯ These findings show that animals tested in the modified EPM showed higher sensitivity to the anxiolytic effects of midazolam than the standard EPM. Antinociception was not a concomitant of the shift in the emotional state present in the retest sessions of the EPM. These results are in agreement with the premises that repeated stressful experience leads to anxiolytic-insensitive fear state different from anxiety.
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Mar 2005
Comparative StudyEffects of scopolamine challenge on regional cerebral blood volume. A pharmacological model to validate the use of contrast enhanced magnetic resonance imaging to assess cerebral blood volume in a canine model of aging.
Cognitive impairment resulting from disruption of cholinergic function may occur through modulation of cerebrovascular volume (CBV). In the present study, dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) was used to examine cerebrovascular volume in young and old dogs during baseline and after administration of a cholinergic antagonist (scopolamine). In the first study, 24 animals (2-15 years of age) were given a baseline scan followed by a second scan after scopolamine administration (30 microg/kg). ⋯ Scopolamine administered before anesthesia however, resulted in higher rCBV values compared to baseline in cerebral gray matter. Additionally, rCBVs were higher in young dogs at baseline in gray and white matter and marginally higher in gray matter when scopolamine was administered before anesthesia. These results indicate that in the dog, rCBV varies with brain compartment, decreases with age, and that DSC-MRI provides a measure of cerebrovascular function which may be related to age-dependent changes in cognition, brain structure, and neuropathology.
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Jan 2005
Case ReportsAcute psychosis following sustained release bupropion overdose.
Bupropion is an antidepressant that is structurally related to amphetamines and enhances dopamine neurotransmission through inhibiting neuronal dopamine re-uptake. Bupropion-related psychosis has been recognized in several papers, but these reports of bupropion-related psychosis almost all involve immediate release (IR) formulation. We present a case of acute psychosis following sustained release bupropion (SR) overdose. ⋯ He developed paranoid delusions 12 h after the bupropion SR overdose. The paranoid symptoms remitted on the third day of his admission. Our case of acute psychosis following bupropion SR overdose indicates the importance of being aware of the rare complication in patients receiving bupropion SR treatment.
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Dec 2004
Comparative StudyIn vivo proton magnetic resonance spectroscopy of the temporal lobe in Alzheimer's disease.
Prior proton magnetic resonance spectroscopy (MRS) studies have consistently reported decreased brain n-acetyl aspartate (NAA) levels and increased myo-inositol (mI) levels in subjects with Alzheimer's disease (AD) relative to healthy comparison subjects. These studies have usually been conducted in small and homogeneous populations of patients with established Alzheimer's disease. Few studies have tested the usefulness of this finding in a general population seeking evaluation for memory loss and other cognitive declines. We designed a study to evaluate the significance of single-voxel proton MRS findings in these patients with memory loss and other cognitive declines. GENERAL METHOD: Thirty-five subjects with a primary complaint of memory loss and other cognitive declines were consecutively referred over a period of 13 months to a specialty clinic. Patients with a diagnosis of mild to moderate probable Alzheimer's disease (N = 22), non-Alzheimer's dementia (depression, multiinfarct dementia, Parkinson's Disease, Korsakoff's Psychosis, and bipolar disorder; N = 13), and healthy comparison subjects (N = 18) were examined with respect to possible differences in metabolites using proton MRS in a 3.4-ml anterior temporal lobe voxel. ⋯ This study found a reduction in the neuronal marker NAA in the anterior temporal lobe of patients diagnosed with probable Alzheimer's disease, using a short add-on proton MRS exam. This change was not observed in patients whose memory loss and other cognitive declines were not attributed to Alzheimer's disease, suggesting that it may aid in the diagnosis or detection of Alzheimer's disease.
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Nov 2004
The protective effect of nebivolol on ischemia/reperfusion injury in rabbit spinal cord.
The aim of this experimental study was to investigate whether nebivolol has protective effects against neuronal damage induced by spinal cord ischemia/reperfusion (I/R). Twenty-one rabbits were divided into three groups: group I (control, no I/R), group II (only I/R) and group III (I/R+nebivolol). Spinal cord ischemia was induced by clamping the aorta both below the left renal artery and above the aortic bifurcation. ⋯ A significant decrease in spinal cord glutathione peroxidase (GSH-Px) level was seen in I/R group and nebivolol treatment prevented the decrement in the spinal cord tissue GSH-Px contents. On the other hand, I/R produced a significant increase in the spinal cord tissue malondialdehyde (MDA) and nitric oxide (NO) contents, this was prevented by nebivolol treatment. In conclusion, this study demonstrates a considerable neuroprotective effect of nebivolol on neurological, biochemical and histopathological status during periods of spinal cord I/R in rabbits.