摘要:

THIS study was undertaken to evaluate the effect of ethanol intake on the anticonvulsive effects of Zonisamide (ZNS), a sulfonamide derivative. EL mice, a strain highly susceptible to seizures, were given a 10% ethanol solutionad libfor 1–4 weeks. Seizures in mice treated with ethanol for 1–3 weeks were decreased by ZNS at a dose of 75 mg kg−1, i.p., but those in mice treated with ethanol for 4 weeks were not suppressed. Serum ZNS concentrations following ethanol consumption for 1–4 weeks were higher than in untreated mice; however, brain ZNS concentrations following ethanol consumption were lower than those in untreated mice. These results suggest that alcohol intake decreases the brain concentration, but not the serum concentration.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

HALOTHANE-anesthetized male rats were subjected to either moderately severe parasagittal fluid percussion- induced traumatic brain injury (TBI) or sham injury, and for 30 min immediately after injury hypoxia was induced in half the rats from each group by substituting a 13% O2source to deliver halothane for continued anesthesia. At 60 min post-TBI, Northern blot analysis showed a significant increase in c-fosmRNA levels, by 60–100% above sham control levels in the frontal cortex, cerebellum and hippocampus. Although hypoxia in sham-injured rats did not by itself alter c-fosmRNA levels, it did significantly potentiate the TBI-induced changes in c-fosmRNA in all three brain regions. These findings show that hypoxia is an important factor influencing genomic responses to TBI.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

THE effect of the natriuretic peptides ANP, BNP and CNP on cGMP formation and immediate early gene expression was investigated in PC12 phaeochromocytoma and C6 glioma cell lines. The three natriuretic peptides were shown to rapidly induce c-fos,TIS8/egr-1andjunBmRNA expression in both cell lines, via stimulation of the cGMP pathway. CNP stimulated cGMP formation and gene induction more potently than the other peptides in C6 cells, and this was statistically significant. In contrast, the three peptides produced similar gene induction in PC12 cells, despite the higher cGMP accumulation evoked by ANP or BNP. CNP was also found to increase DNA binding activity of the transcription factor AP1 in both cell types, demonstrating that natriuretic peptides potentially regulate key cellular gene expression.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

MUSCLE fibres of the rat diaphragm kept in a tissue culture medium became depolarized by 8–10 mV within 3 h after denervation. In the presence of carbachol (CB; 5 × 10−8M), and acetylcholine (ACh; 5 × 10−8M, the postdenervation depolarization was reduced. Both drugs were used in concentrations which mimicked the effect of non-quantal release of ACh. (+)Tubocurarine (TC) and ouabain did not prevent the protective action of CB, indicating that this effect is not mediated through ACh nicotinic receptors or the electrogenic Na+,K+pump. Addition of Mg2+, verapamil, diltiazem, nifedipine and Cd2+in concentrations which block Ca2+entry virtually inhibited the effect of both cholinomimetics. L-Nitroarginine methylester (NAME), an inhibitor of NO synthase, and haemoglobin, an extracellular scavenger of the NO radical, completely eliminated the protective effect of CB on post-denervation depolarization. The retrograde action of NO produced by cholinomimetics on nerve terminals is postulated.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

TO investigate the involvement of immediate early genes (IEGs) in the ambulatory activity induced by a low dose of methamphetamine (MAP) in mice, we injected an antisense phosphorothioate oligodeoxynucleotide (ODN) to c-fosmRNA stereotactically into the striatum of ddY male mice. MAP (2 mg kg−1)-induced ambulatory activity was significantly suppressed when the mouse was pretreated by the ODN (2 mM, 1 μl), and this was accompanied by a decrease in c-Fos-like protein immunoreactivity. Repetitive intermittent administration of MAP at intervals of 3 days confirmed that the suppressive effect was transient and reproducible. These results suggest that c-Fos is at least partly the key molecule regulating the psychomotor stimulation by MAP in mouse brain.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

CHANGES in sensitivity of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) subtype of glutamate receptors following the induction of longterm potentiation (LTP) were investigated in rat hippocampal slices. AMPA was ejected into the stratum radiatum of the hippocampal CA1 region by pressure ejection and the response recorded intracellularly. Responses to AMPA exhibited a fast increase (2–3 min) following LTP induction: the time course of this increase paralleled the potentiation of the excitatory postsynaptic current (EPSC). In cases where there was no increase in the slope of intracellularly recorded EPSC following tetanization, no increase of the AMPA responses was observed. These results suggest that increases in postsynaptic AMPA sensitivity can underlie short-term potentiation (STP) and thus, support a postsynaptic locus for both STP and LTP.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

TO determine whether calmodulin plays a role in neurodegeneration after ischemia, effects of the selective calmodulin inhibitors calmidazolium and W7 were studied in organotypic cultures of rat hippocampus. Protection of pyramidal cells in the CA1 region of the hippocampus by calmidazolium and W7 against hypoxia/hypoglycemia suggests that activation of intracellular calmodulin plays a significant role in ischemic neuronal injury. Both ryanodine and TMB-8, inhibitors of intracellular Ca2+release, failed to prevent ischemic neuronal injury. These results indicate that calmodulin, a major intracellular Ca2+binding protein, plays a significant role in experimental ischemia-induced hippocampal neuronal injuryin vitro.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

PLASMINOGEN activators (PAs) have been suggested to play a role in neuronal migration and glial cell proliferation in the developing CNS. Less is known, however, about the role of PAs in the mature nervous system. To elucidate the role of tissue type plasminogen activator (tPA) in the nervous system we usedin situhybridization to study the expression of tPA mRNA within the rat facial nucleus after facial nerve transection. We also studied the effect of MK-801 on tPA mRNA expression in order to investigate whether the previously reportedN-methyl-D-aspartate (NMDA) receptor activation is involved in this model. tPA mRNA was expressed in the ipsilateral facial motoneurones from 6 h after injury. This expression continued for at least 2 weeks after facial nerve transection. Administration of MK-801 before axonal injury did not affect the expression of tPA mRNA in the facial nucleus. These data suggest that tPA might be involved in the regenerative process without NMDA receptor activation in mature facial neurones.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

THE novel opioid receptor ORL1 is widely distributed throughout the CNS of the rat, and is present in high densities in several brain regions known to participate in the control of food intake. We injected a recently identified endogenous agonist of this receptor, nociceptin, into two of these feeding-related areas. Microinjections of nociceptin (2.5–25 nmol) into either the ventromedial hypothalamic nucleus or the nucleus accumbens shell significantly increased food intake in rats. We believe this to be the first report of a specific effect of nociceptin on a motivated behavior.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

WE used primary cultures of rat hippocampal tissue to estimate the contribution of anion exchange (AE) proteins to the regulation of intracellular pH in neurones and astrocytes. After induction of acidosis, neonatal rat astrocytes were able to restore the intracellular pH in the absence of extracellular bicarbonate. Neonatal neurones, however, were able to recover from acidosis only when bicarbonate was present in the extra- cellular medium. This recovery was inhibited by inhibition of anion exchange and was independent of the presence of sodium ions. Antibodies against AE proteins reacted predominantly with neurones. These data suggest that neurones in particular are dependent on functional AE proteins for the maintenance of their intracellular pH.

ISSN:0959-4965    

出版商:OVID    

年代:1997

数据来源: OVID