摘要:

WE report here that, in cultured cerebellar granule cells, the CXC chemokine GRO β stimulates the signaling pathway of the extracellular signal-regulated kinases, and enhances both evoked and spontaneous post-synaptic currents in patch clamped Purkinje neurons from rat cerebellar slices. The GRO β-induced enhancement of the excitatory post-synaptic currents evoked by stimulating the parallel fibres is blocked by the inhibitor of the extracellular signal-regulated kinases pathway PD98059, which also reduces both basal frequency of spontaneous post-synaptic currents and mean amplitude of evoked excitatory post-synaptic currents. Our results suggest that GRO β modulates neurotransmitter release in the cerebellum through the activation of the extra-cellular signal-regulated kinases pathway.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

OCCLUSION of the rodent middle cerebral artery by embolism, using an intraluminal filament, produces behavioral alterations which resemble many symptoms associated with stroke. This model has been used to examine treatment interventions for the disease, however, variable success rate in completely blocking the middle cerebral artery may present inconclusive interpretation of the data. To detect successful occlusion of the middle cerebral artery, we demonstrate here sensitive and reliable behavioral parameters including the elevated body swing test, the postural tail-hang test, the spontaneous rotational test, and the forelimb akinesia test. These assays provide a criterion for identifying animals with incomplete occlusion which could promote host-related spontaneous recovery and might confound true effects of experimental therapies on ischemia-induced dysfunctions. From a practical standpoint, the early reliable identification of partial cerebral ischemia aids in immediate and efficient adjustments of the surgical procedure to create a complete and stable ischemia stroke animal model.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

FLUROTHYL kindling initiates a time-dependent process that results in a facilitated propagation from the fore-brain to the brainstem seizure system and in an increase in the complexity of behavioral seizure expression. We investigated the involvement of the ventromedial nucleus of the hypothalamus (VMH) in mediating this facilitated propagation between these seizure systems. Bilateral ibotenic acid lesions of the VMH, but not the dorsomedial nucleus of the hypothalamus (DMH), resulted in a disruption in the propagation of seizure activity from the forebrain to the brainstem. Moreover, VMH lesioned mice were able to express brainstem seizures following minimal corneal electroconvulsive shock (mECS). Together, our results indicate that the VMH is a critical substrate involved in propagating seizure activity between the forebrain and brainstem, but is not involved in the expression systems necessary for forebrain or brainstem seizure manifestations.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

WE measured regional cerebral blood flow (rCBF) during unimanual and bimanual movements using H215O PET. Six healthy volunteers performed unimanual, bimanual-symmetric and bimanual-asymmetric ballistic finger movements. The study was designed to minimize anticipation and preparation of movements. Data were analysed using SPM. Unpredictably paced unimanual movements resulted in significant activation of contra-lateral primary motor-somatosensory cortex (M1-S1) and mesial frontal cortex (p≤ 0.001). Performance of symmetric bimanual movements resulted in bilateral activation, but no additional activation of mesial frontal cortex was shown. Comparison of asymmetric with symmetric bimanual movements revealed additional recruitment of mesial frontal cortex (p≤ 0.001). We suggest that rostral mesial frontal cortex facilitates asymmetric non-mirrored bimanual finger movements.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

SUPERFAST myosin heavy chain (MHC), which is found in jaw-closing muscle and extraocular muscle (EOM), may also be found in rat laryngeal muscles. Immunostaining and Western blot using anti-EOM antibody were performed to identify and localize EOM MHC in laryngeal muscles. Specific reactivity of laryngeal IIL MHC was confirmed by Western blot and on immunostaining, all fibers in the lateral part of thyroarytenoid muscle reacted with EOM antibody. A scattered pattern of positive fibers was observed in the medial part of the thyroarytenoid, the posterior cricoarytenoid and the lateral cricoarytenoid muscles. EOM MHC was not detected in the cricothyroid muscle. The expression of EOM MHC in rat laryngeal muscle is consistent with the functional demands of the airway protection reflex.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE present study examined the efficacy of single and combined treatments with an anticholinesterase, tetrahydroaminoacridine, nicotine and a glycine-B site partial agonist, D-cycloserine, in alleviating the water maze reversal learning defect induced by a medial septal lesion. D-cycloserine (3 and 10 mg/kg) improved reversal learning. Tetrahydroaminoacridine (1 and 3mg/kg) and nicotine (0.1 and 0.3 mg/kg) had no effect on reversal learning. A combination of tetrahydroaminoacridine 3 mg/kg or nicotine 0.3 mg/kg and D-cycloserine 10 mg/kg was not more effective than D-cycloserine 10 mg/kg alone in improving reversal learning. This suggests that stimulation of NMDA mechanisms may more effectively improve in medial septal-lesioned rats reversal learning processes than stimulation of cholinergic activity.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

CHOLINERGIC stimulation in the basal forebrain (BF) triggers cataplexy in canine narcolepsy. Extracellular single unit recordings in the BF were carried out in freely moving narcoleptic dogs to study the neuronal mechanisms mediating cataplexy induction in the BF. Among the 64 recorded neurons, 12 were wake-active, three were slow wave sleep (SWS)-active, 17 were wake-/ REM-active, 11 were REM sleep-active, three were cataplexy-active, and the other 18 were state-independent. Systemic administration of physostigmine, a cholinesterase inhibitor, induces status cataplecticus, decreases SWS and increases acetylcholine levels in the BF. Firing of most of the state-dependent neurons in the BF was significantly modified by physostigmine. Some of these neurons may thus mediate sleep stage changes or the effect on cataplexy observed after cholinergic stimulation in the BF.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

TETANIC stimulation of high-threshold primary afferent fibers in the dorsal root was found to elicit intrinsic optical signals (IOSs) in transverse slices of 11 to 20-day-old rat spinal cords. The IOS, lasting for 30 s or longer, was most prominent in the lamina II of the dorsal horn. Treatment with a Na+-K+-2Cl−co-transport blocker, furosemide, abolished the IOS, suggesting that the origin of the IOS is the cellular swelling due to an activity-dependent rise in extracellular K+. Substance P antagonist spantide, glutamate antagonists 2-amino-5-phosphonovaleric acid and 6-cyano-7-nitroquinoxaline-2,3-dione, and the μ-opioid agonist [d-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin suppressed IOSs. Thus, IOSs represent at least in part the slow excitatory response that is known to be generated in dorsal horn neurons after tetanic activation of unmyelinated afferent fibers.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE functional magnetic resonance (fMRI) technique can be robustly used to map functional activation of the visual pathway including the primary visual cortex (V1), the lateral geniculate nucleus (LGN), and other nuclei of humans during visual perception stimulation. One of the major controversies in visual neuroscience is whether lower-order visual areas involve the visual imagery process. This issue was examined using fMRI at high magnetic field. It was demonstrated for the first time that the LGN was activated during visual imagery process in the human brain together with V1 and other activation. There was a tight coupling of the activation between V1 and the LGN during visual imagery.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE neurotrophin-3 (NT-3) gene has previously been reported to consist of three exons including two 5′ short untranslated exons and a 3′ long exon encoding the entire protein, and to give rise to two classes of transcripts by alternative splicing of the 5′ exons to the 3′ coding exon. In the present study, we demonstrated the presence of at least four new classes of transcripts of the NT-3 gene, in addition to the two known transcripts. The present finding proposes the further complexity of the regulational mechanism for NT-3 expression.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID