摘要:

THE monoamine oxidase-B inhibitor L-deprenyl (Selegiline) is effective in treating Parkinson's disease and possibly Alzheimer's disease. The neuroprotective property of L-deprenyl may be unrelated to the inhibition of monoamine oxidase-B. Since nitric oxide (NO) modulates activities including cerebral blood flow and memory, we examined the effect of L-deprenyl on NO. L-Deprenyl induced rapid increases in NO production in brain tissue and cerebral vessels. Vasodilation was produced by endothelial NO-dependent as well as NO-independent mechanisms in cerebral vessels. The drug also protected the vascular endothelium from the toxic effects of amyloid-β peptide. These novel actions of selegiline may protect neurons from ischemic or oxidative damage and suggest new therapeutic applications for L-deprenyl in vascular and neurodegenerative diseases.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE effects of C-type natriuretic peptide (CNP) on the hypothalamo-pituitary-adrenal system response to different stressors was studied. Various doses of CNP (0.2, 2, 4 μg) were injected into the lateral cerebral ventricle of freely moving rats 30 min before stress and activation of the adrenal was measured by plasma corticosterone. CNP did not affect basal corticosterone secretion in the doses applied, but inhibited in a dose-dependent manner the increase in plasma corticosterone induced by ether stress, electric shock and restraint. CNP exerted a more profound inhibitory effect on the response to ether stress than on that to electric shock or restraint. These results suggest that CNP acts centrally and to a different extent on the responses to different stresses.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

INVOLVEMENT of the cerebral serotoninergic system has been invoked to explain the origin of the pain and the vascular phenomena in migraine. To further investigate the type of cerebral serotonin receptors that may be altered in migraine, the prolactin (PRL) and cortisol responses to m-chlorophenylpiperazine (mCPP), a selective 5-HT1A,-5-HT2A/Creceptor agonist, were monitored in 12 patients suffering from migraine without aura and in 14 matched healthy controls. Each subject underwent two challenges, one with mCPP (0.5 mg/kg) and the other with placebo (orally) using a double-blind crossover design. Anxiety level was measured by the State Trait Anxiety Inventory. Migraine patients had a greater PRL response to mCPP (p= 0.05) and greater anxiety (p< 0.01) than controls; cortisol response to mCPP did not differ suggesting that 5-HT2Creceptors are normal in migraine. Augmented PRL response to mCPP could derive from 5-HT1Areceptor hypersensitivity, perhaps as as a consequence of anxiety due to pain expectation. Cerebral 5-HT1Ahypersensitivity could also explain the increased occurrence of migraine attacks during anxiety.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

IN VITROstudies tested the efficacy of three caspase inhibitors, Ac-VAD-cmk (caspase-1 inhibitor), z-DEVD-fmk (caspase −3 inhibitor) and B-D-fmk (BOCDFK, a general inhibitor), for protecting auditory sensory cells from cisplatin-damage induced loss. Treatment of 3-day-old rat organ of Corti explants with these caspase inhibitors protected > 80% of the auditory hair cells from cisplatin-damage initiated apoptosis. Dissociated cell cultures of 3-day-old rat spinal ganglia treated with any of these three caspase inhibitors in addition to exogenous neurotrophin have highly significant increases in neuronal survival following cisplatin exposure. These results indicate that loss of auditory sensory cells as a result of cisplatin-induced damage involves apoptosis and that blocking of this cell death pathway at the caspase level effectively rescues both hair cells and neurons.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

APOLIPOPROTEIN E-(apoE) deficient mice exhibit hypercholesterolemia, accelerated atherosclerosis and increased infarct size after middle cerebral artery occlusion (MCAO). This study examined whether worsened ischemic outcome is attributable to effects of apoE deficiency on cerebral circulation. Wild type and apoE-deficient mice underwent MCAO and autoradigraphic measurement of cerebral blood flow. Circle of Willis anatomy was examined in non-ischemic animals. Both groups exhibited similar reduction in blood flow. Both groups had 100% incidence of filling of the anterior communicating artery. The posterior communicating artery (PcomA) filled in 70% of wild type and 80% of apoE-deficient mice. Both groups had considerable variability in relative sizes of the PcmA. This study indicates that worsened outcome from MCAO of apoE-deficient mice is not attributable to any detectable vascular effects and offers validity to use of apoE-deficient mice for study of apoE as a factor in cerebral ischemic pathophysiology.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

OFFSET auditory responses were investigated by electroencephalography mainly in the 1970s, but since then no particular attention has been paid to them. Among the studies using magnetoencephalography (MEG) devices there are, to our knowledge, only three studies of the auditory off-response, and no significant variance has ever been observed between the source locations of on- and off-responses elicited from pure tones. We measured auditory evoked magnetic fields (AEFs) to various frequency pure tone stimulation in 5 healthy subjects with a 122-channel helmet-shaped magnetometer, and compared the distributions of the source locations of auditory N100m-Off (magnetic off-response around 100 ms) with those of N100m-On. Their spatial distributions were quite close to each other, and yet they were significantly different.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

USING principal component analysis, we studied trial to trial, spontaneous variability of evoked potentials (EPs) recorded from rat barrel cortex after whisker stimulation. This method allowed for extraction of two distinct components of EP which overlapped in the time domain. Our results are consonant with the previously described depth distribution of current sources and the extracted components can be therefore attributed to activities of two pyramidal cell classes: supra- and infragranular. Qualitatively similar results were found in both anaesthetized and alert animals.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

TO investigate the neural mechanisms involved in shifting attention we used positron emission tomography to examine regional cerebral blood flow (rCBF) during a task that demands shifting attention between color and shape. Significant activation was observed in the right dorsal prefrontal cortex and parieto-occipital cortex at all frequencies of attention shifts. The frequency of shifts between categories correlated significantly with rCBF in the rostral part of the supplementary motor area and the left precuneus, whereas the number of successive correct responses correlated with rCBF in the orbitofrontal cortex and the caudate nucleus. This study suggests that several prefrontal regions may participate in the processes of shifting attention in different ways.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

IN adult rat, immunostaining for pituitary adenylate cyclase activating polypeptide (PACAP) was demonstrated in the soma and dendrites of Purkinje cells and in nerve fibres around granule cells. PACAP in the Purkinje cells was confirmed by the presence of mRNA. The concentration of PACAP-38 was high after birth and declined to adult levels within a few weeks. At birth PACAP-immunoreactive nerve fibres and a few cells were present in the Purkinje cell layer, but already at postnatal day 7 an adult PACAP immunostaining pattern was found. The findings suggest that PACAP could be a neurotransmitter in the adult cerebellum and provide a morphological correlate for the reportedin vitroanti-apoptotic PACAP effects on cerebellar granule cells from 1-week-old rats.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

WE describe a patient who in 1983 suffered a stroke which resulted in severe hemiplegia and somatosensory loss. His neurological condition remained stable until January 1996, when, because of a myocardial infarction, the patient underwent systemic thrombolytic therapy which led to a remarkable improvement of both motor and somatosensory functions. This finding suggests the existence of 'idling neurons' which remain viable for a long time after stroke, and opens a fascinating window on the therapeutic potential of thrombolytic therapy in chronic stroke patients.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID