mRNA In Cerebral Cortex Research Articles

Effect of electroacupuncture of Governor Vessel on expression of GAD67 and GABA-T in cerebral cortex of rats with post-stroke limb spasticity

To observe the effect of electroacupuncture (EA) of Governor Vessel (GV) on the expressions of glutamate decarboxylase 67 (GAD67) and γ-aminobutyric acid transaminase (GABA-T) in the cerebral cortex of rats with post-stroke limb spasticity, so as to explore its mechanism underlying improvement of limb spasticity. Twenty four male SD rats were randomly and equally divided into control, sham operation, model, and EA groups. The cerebral ischemia model was established by occlusion of the middle cerebral artery (MCAO). EA (100 Hz, 1-3 mA) was applied to "Dazhui"(GV14), "Jizhong"(GV6) and "Houhui"( anteromedial of transverse process of the sixth lumbar vertebra) for 30 min, once daily for 7 consecutive days. The neurologic deficit score (0-5 points) was evaluated according to Zea Longa's method, and the muscular tension severity (0-5 points) was assessed according to the modified Ashworth muscle tone rating scale, and the tension signals of the quadriceps ferroris of the affected limb were recorded using tonotransducer and BL-420F electrophysiological recorder. The expression levels of GAD67 and GABA-T proteins and mRNAs in the cerebral cortex were detected by immunohistochemistry, fluorescence quantitative real-time PCR and Western blot, separately. After modeling, the neurological deficit score, muscle tone score, and the expression levels of GABA-T mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly decreased (P<0.01) in the model group relevant to the control and sham operation groups. Following the intervention, the neurological deficit score, muscle tone score, and expression levels of GABA-T mRNA and protein in cerebral cortex were significantly decreased (P<0.01), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05) in the EA group in contrast to the model group. EA stimulation of Governor Vessel can ameliorate the limb spasticity symptom in MCAO rats, which may be associated with its functions in increasing the expressions of GAD67 protein and mRNA and inhibiting the expressions of GABA-T protein and mRNA, thereby playing the inhibitory role of GABA.

Effects of mild hypothermia on expression of NF-E2-related factor 2 and heme-oxygenase-1 in cerebral cortex and hippocampus after cardiopulmonary resuscitation in rats.

Objective(s):The aim of this study was to investigate the effects of mild hypothermia on expression of NF-E2-related factor 2 (Nrf2) and heme-oxygenase-1 (HO-1) of rat cerebral cortex and hippocampus after cardiopulmonary resuscitation and further investigate the possible mechanism of action.Material and Methods:To copy an asphyxia heart arrest model, Sprague Dawley rats were randomly divided into normothermia group, mild hypothermia group before restoration of spontaneous circulation (ROSC), and mild hypothermia group after ROSC. Body temperature in normothermia group was maintained at 37.5-39 °C, while in mild hypothermia group maintained at 32-34 °C by surface cooling with the ice pack. Each group then divided into three subgroups: 15 min, 30 min, and 60 min. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect the expression of Nrf2 and HO-1 mRNA in cerebral cortex and hippocampus. Hematoxylin-eosin (H&E) staining was performed to observe histological changes. Immunohistochemistry was performed to detect the expression of Nrf2 and HO-1 protein expression.Results:The expression of Nrf2 and HO-1 in cerebral cortex and hippocampus after cardiopulmonary resuscitation (CPR) was significantly increased and mild hypothermia up regulated this level. HE staining showed that mild hypothermia significantly improved neuronal injury.Conclusion:Mild hypothermia has neuroprotective effects on cerebral ischemia/reperfusion injury after cardiac arrest. The possible mechanism is that Nrf2-ARE pathway in cerebral cortex and hippocampus after CPR is activated.

Interdependent adrenergic receptor regulation of Arc and Zif268 mRNA in cerebral cortex

Norepinephrine is a neurotransmitter that signals by stimulating the α1, α2 and β adrenergic receptor (AR). We determined the role of these receptors in regulating the immediate early genes, Activity Regulated Cytoskeleton Associated Protein (Arc) and Zif268 in the rat cerebral cortex. RX821002, an α2-AR antagonist, produced Arc and Zif268 elevations across cortical layers. Next we examined the effects of delivering RX821002 with an α1-AR antagonist, prazosin, and a β-AR antagonist, propranolol. RX821002 given with a prazosin and propranolol cocktail, or with each of these antagonists individually, decreased Arc and Zif268 to saline-treated control levels in most cortical layers. Arc and Zif268 levels were also similar to saline-treated control levels when rats were given a prazosin and propranolol cocktail alone, or when each of these antagonists were delivered individually. Taken together, these data reveal that α2-AR uniquely exert a tonic inibitory regulation of both Arc and Zif268 compared to α1 and β-AR. However, the ability of RX821002 to increase Arc and Zif268 is interdependent with α1 and β-AR signaling.

Zinc distribution in mouse brain by SRXRF

In order to explore the interaction between the expression of ZnT3 (Zinc Transporter 3) mRNA (Messenger Ribonucleic Acid) and the concentration of elemental zinc in mouse brain, zinc distribution in brain was determined by synchrotron radiation X-ray fluorescence (SRXRF) technique and a ZnT3 mRNA expression in tissue was examined by the reverse-transcriptase polymerase chain reaction (RT-PCR) method.The results show that the zinc concentration is not evenly distributed in brain slices. Its concentrations in cerebral cortex and hippocampus are nearly 5-10 times higher than those in other positions. A corresponding relation is that ZnT3 mRNA in cerebral cortex, hippocampus and testis has higher abundant degree, but it is not examined out in other tissues. Furthermore, the results promote that ZnT3 facilitates the accumulation of zinc in synaptic vesicles and may play an important role in structuring of vesicular zinc pool.

T 3 strongly regulates GLUT1 and GLUT3 mRNA in cerebral cortex of hypothyroid rat neonates

Experimental hypothyroidism alters the expression of the GLUT1 and GLUT4 glucose transporters in brown adipose tissue, skeletal muscle and heart. Congenital hypothyroidism disrupts the development and function of the CNS, and the importance of GLUT1 for proper brain function has been dramatically evidenced in the cases of GLUT1 deficiency syndrome. Because of this, we hypothesised that the expression of GLUT1 and GLUT3, glucose transporters expressed in brain cortex, may be altered in congenital hypothyroidism. GLUT3 mRNA was induced during postnatal development whereas GLUT1 mRNA was initially repressed and further induced; both processes were essentially similar in control and hypothyroid animals. Under these conditions GLUT1 protein expression was reduced in cerebral cortex from 15-day-old hypothyroid neonates, which suggests the existence of post-transcriptional alterations. The most striking differences were observed when hypothyroid animals at different developmental stages were treated acutely with T 3. GLUT1 and GLUT3 mRNA expression behaved in opposite ways in response to treatment with the hormone. Furthermore, the behaviour of each glucose transporter isoform against T 3 was not uniform but changed alongside development. In all, our data show that the regulation of GLUT1 and GLUT3 in cerebral cortex is regulated by T 3 in a complex way and suggest that alterations in the expression of glucose transporters induced by hypothyroidism might have a functional impact on brain glucose uptake.

Effects of Naohuandan Recipe on learning and memory abilities of SAM-P/8 mice and its role in anti-oxidation and anti-apoptosis

To investigate the effects of Naohuandan Recipe on learning and memory abilities of SAM-P/8 mice and its role in anti-oxidation and anti-apoptosis. Forty SAM-P/8 mice were randomly divided into four groups, which were untreated (normal saline-treated) group, Yinkeluo Tablets (extracts of gingko leaf)-treated group, low-dose Naohuandan Recipe-treated group and high-dose Naohuandan Recipe-treated group. Mice in these groups were given corresponding drugs orally for 105 days. Then the performances of learning and memory of mice were tested by a step-down passive avoidance task and a Y-maze test. The serum levels of superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were detected. The expression level of bcl-xl mRNA in cerebral cortex and hippocampus of mice was detected by reverse transcription-polymerase chain reaction (RT-PCR). The performances of learning and memory in the Yinkeluo Tablets-treated group, low- and high-dose Naohuandan Recipe-treated groups were significantly improved as compared with those in the untreated group (P<0.05 or P<0.01), and such performance was the best in the high-dose Naohuandan Recipe-treated group among these four groups (P<0.01). The serum levels of SOD and GSH-Px and the expression of bcl-xl mRNA in cerebral cortex and hippocampus of mice in the Yinkeluo Tablets-treated group, low- and high-dose Naohuandan Recipe-treated groups were also significantly higher than those in the untreated group (P<0.05 or P<0.01), while the serum level of MDA in the untreated group was higher than that in the other three groups (P<0.01). Naohuandan Recipe can improve learning and memory abilities of SAM-P/8 mice, and this effect may be related to its anti-oxidation efficacy and enhancement of expression level of bcl-xl mRNA.

Expression of androgen receptor gene in cerebral cortex and hippocampus of rats with perinatal hypothyroidism

To investigate the effects of perinatal thyroid hormone deficiency on the expression of androgen receptor (AR) mRNA in cerebral cortex and hippocampus of rats. Perinatal hypothyroidism was induced by the administration of propylthiouracil (PTU) solution to the dams by gavage (50 mg/d) beginning at embryonic d15 throughout the lactational period. In the T(4) injected group hypothyroid rats were injected intraperitoneally with levothroxine (L-T(4)) 2 microg/100 g BW daily, starting from the day of birth. Cerebral cortex and hippocampus specimen were collected from controls,hypothyroid and T(4)-injected hypothyroid rats on postnatal d1, 5, 10, 15 and 20. Quantification of ARmRNA in cerebral cortex and hippocampus was performed with competitive RT-PCR using internal and external standardization. Age-related increasing ARmRNA levels were observed in neonatal rats, and those in male animals were significantly higher. AR expression was higher in the hippocampus than in the cerebral cortex. ARmRNA levels in the hypothyroid pups were lower than those in age-matched controls. The mRNA levels in the T(4)-injected hypothyroid pups were significantly higher compared with the age-matched hypothyroid pups, but in hippocampus ARmRNA expression did not reach normal levels in male rats at d10 and d20, in female at d15 and d20. The expression of ARmRNA decreases in brain of rats with perinatal hypothyroidism. Treatment with thyroid hormone can recover ARmRNA expression in cerebral cortex, but not in hippocampus.

Developmental changes in the expression of growth-associated protein-43 mRNA in the monkey thalamus: Northern blot and in situ hybridization studies

The expression of growth-associated protein-43 has been related to axonal elongation and synaptic sprouting. Using the Northern blot analysis, we investigated the developmental changes of growth-associated protein-43 mRNA in the thalamus of macaque monkeys. The amount of growth-associated protein-43 mRNA was high at embryonic day 125, and decreased at postnatal day 1. It increased again at postnatal day 8, reached its peak value at postnatal days 50–70, and then decreased gradually until postnatal year 1. We previously reported that the amount of growth-associated protein-43 mRNA in the cerebral cortex decreased roughly exponentially during perinatal and postnatal periods and that it approached the asymptote by postnatal day 70 [Oishi T, Higo N, Umino Y, Matsuda K, Hayashi M (1998) Development of GAP-43 mRNA in the macaque cerebral cortex. Dev Brain Res 109:87–97]. The present findings may indicate that extensive synaptic growth of thalamic neurons continues even after that of cortical neurons has finished. We then performed in situ hybridization to investigate whether the expression level of growth-associated protein-43 mRNA was different among various thalamic nuclei. In the infant thalamus (postnatal days 70–90), moderate to intense expression of growth-associated protein-43 mRNA was detected in all thalamic nuclei. Quantitative analysis in the infant thalamus indicated that the expression levels were different between the nuclear groups that are defined by the origin of their afferents. The expression in the first order nuclei, which receive their primary afferent fibers from ascending pathways [Guillery RW (1995) Anatomical evidence concerning the role of the thalamus in corticocortical communication: a brief review. J Anat 187 (Pt 3):583–592], was significantly higher than that in the higher order nuclei. While moderate expression was also detected in the adult dorsal thalamus, the expression in the first order nuclei was almost the same as that in the higher order nuclei. Thus, the in situ hybridization experiments indicated that the transient postnatal increase in the amount of growth-associated protein-43 mRNA, which was shown by the Northern blot analysis, was mainly attributed to enhanced expression in the first order nuclei during the postnatal period. This may be a molecular basis for environmentally induced modification of thalamocortical synapses.

Importance of NO/cGMP signalling via cGMP‐dependent protein kinase II for controlling emotionality and neurobehavioural effects of alcohol

Cyclic GMP is a second messenger for nitric oxide (NO) that acts as a mediator for many different physiological functions. The cGMP-dependent protein kinases (cGKs) mediate cellular signalling induced by NO and cGMP. Here, we explored the localization of cGMP-dependent protein kinase type II (cGKII) in the mouse brain. In situ hybridization revealed high levels of cGKII mRNA in cerebral cortex, thalamic nuclei, hypothalamic nuclei, and in several basal forebrain regions including medial septum, striatum and amygdala. The close link to NO and the distribution pattern of cGKII suggested that this enzyme might be involved in emotional reactions and responses to drugs of abuse. Therefore, cGKII knockout animals (cGKII-/-) were compared with littermate controls in behavioural tests (i) for emotion-linked and (ii) for acute and chronic ethanol responses. Deletion of cGKII did not influence aggressive behaviour but led to enhanced anxiety-like behaviour. In terms of acute responses to ethanol, cGKII-/- mice were hyposensitive to hypnotic doses of ethanol as measured by the loss of righting reflex, without an alteration in their blood alcohol elimination. In a two-bottle free choice test, cGKII-/- mice showed elevated alcohol consumption. No taste differences to sweet solutions were observed compared to control animals. In summary, our data show that cGKII activity modulates anxiety-like behaviour and neurobehavioural effects of alcohol.

Characterization of NPY mRNA-expressing cells in the human brain: co-localization with Y2 but not Y1 mRNA in the cerebral cortex, hippocampus, amygdala, and striatum

Neuropeptide Y (NPY) is one of the most abundant peptides in the central nervous system. Its effects on, for example, cognition, memory and motor functions are thought to be mediated mainly via its interactions with the NPY Y1 and Y2 receptor subtypes. We had previously described the neuroanatomical organization of the Y1 and Y2 mRNA expression in humans. However, in view of the lack of information regarding the overall detailed distribution of NPY mRNA expression in the human brain, a complete picture of the anatomical organization of the NPY-related genes was still missing. Thus, in the present study, the regional distribution of NPY mRNA-expressing cells was analyzed in the post-mortem human brain. In addition, double labeling in situ hybridization was performed to characterize the NPY neuronal populations in relation to the Y1 and/or Y2 receptor mRNA localization in the human cerebral cortex, striatum, and amygdala. NPY mRNA was found to be abundant in layers II and VI of the neocortex, polymorphic layer of the dentate gyrus, basal ganglia, and amygdala. Double labeling in situ hybridization showed the co-expression of NPY mRNA with the Y2, but not with the Y1, mRNA in the human cerebral cortex, hippocampus, amygdala, striatum, and nucleus accumbens, and the existence of co-expression of the Y1 and Y2 mRNAs in the cerebral cortex and amygdala. Overall, these results suggest a role for the Y2, but not Y1, as an autoreceptor in the NPY neuronal populations of the human brain.

Opposite Regulation of Basic Fibroblast Growth Factor and Nerve Growth Factor Gene Expression in Rat Cortical Astrocytes Following Dexamethasone Treatment

Growth factors are peptides that exert different activities in the CNS, supporting the survival of different cell populations and playing an important role in the maintenance of cell homeostasis. Much evidence has suggested that these molecules can protect neurons from degeneration induced by mechanical injury or excitotoxic stimuli. Different factors can contribute to the regulation of neurotrophic factor expression in the brain. Such mechanisms may therefore be important in the manipulation of the levels of these peptides in specific brain areas as a therapeutic intervention in acute and chronic neurodegenerative diseases. We have used a primary culture of rat cortical astrocytes to investigate the regulation of basic fibroblast growth factor (bFGF) gene expression in comparison with other neurotrophic molecules. Our results indicate that the glucocorticoid analogue dexamethasone markedly elevates bFGF mRNA levels but reduces the expression of nerve growth factor. The induction of bFGF was transient, as it peaked after 6 h and returned to basal levels within 24 h and was not blocked by coincubation of cycloheximide, thus indicating that it did not require de novo protein synthesis. This effect was also observed in vivo, as systemic injection of dexamethasone (1 or 10 mg/kg) produced a significant increase in the amount of bFGF mRNA in cerebral cortex and hippocampus. The effect we describe can contribute to the regulation of bFGF expression in the brain and may be important in relation to the protective effect exerted by this growth factor in different models of neuronal injury.

Differential temporal patterns of expression of immediate early genes in cerebral cortex induced by intracerebral excitotoxin injection: Sensitivity to dexamethasone and MK-801

A number of conditions associated with persistent excitation such as electrically and chemically-induced seizures cause a rapid increase in the expression of immediate early genes (IEG) such as c- fos. In this study the time-course of induction of c- jun, jun-B and zif 268 mRNA by kainate was characterized in rat cerebral cortex and compared to that of c- fos mRNA induction. Unilateral injection of kainate into the nucleus basalis caused a significant induction of c- jun mRNA in cerebral cortex from 4 hr which was maximal at 8 hr, being 3 times greater in ipsilateral cortex than in control cortex. This pattern was also shown for jun-B and was similar, but of small magnitude, to that obtained with c- fos mRNA, with a maximal increase at 8 hr, whilst the maximal induction of zif-268 mRNA preceded these responses occurring at 4 hr. A marked difference was seen in duration in the c- jun induction which was maintained at a high level for at least 24 hr. Treatment of animals with MK-801 (within 30 min of injection of kainate) or dexamethasone (2–30 mg/kg) at the time of kainate injection significantly attenuated the response. The induction of c- fos mRNA by kainate injection was most sensitive to dexamethasone (2 mg/kg), whereas a higher dose (30 mg/kg) was required to attenuate the induction of zif-268 mRNA. These results show that a time-dependent and co-ordinated induction of c- fos, c- jun, jun-B and zif-268 mRNA in cerebral cortex occurs in response to the persistent excitation caused by excitotoxin injection which is mediated by glutamate and shows a differential sensitivity to dexamethasone.

Induction of nerve growth factor and basic fibroblast growth factor mRNA following clenbuterol: Contrasting anatomical and cellular localization

RNase protection assay and in situ hybridization were used to analyze the temporal and cellular changes in nerve growth factor (NGF) and basic fibroblast growth factor (bFGF) mRNA content evoked by the lipophilic β-adrenergic receptor agonist clenbuterol in adult rat brain. Clenbuterol elicited a threefold increase in NGF mRNA expression which was limited to the cerebral cortex. This increase was maximal at 5 h, still evident by 10 h, and declined to control levels by 24 h. By 10 h NGF protein was also increased. Elevated NGF mRNA hybridization following clenbuterol was localized in the superficial cortical layers II and III in large Nissl-pale cells, suggesting that NGF mRNA induction occurs in neurons. In the same animals, clenbuterol induced a twofold increase in the levels of bFGF mRNA in cerebral cortex and hippocampus. This increase was localized primarily in glial cells as demonstrated by bFGF mRNA hybridization over all cortical regions and by labeling of the stratum lacunosum moleculare of the hippocampus. Our results suggest that enhanced noradrenergic tone regulates expression of these two trophic factors by different synaptic mechanisms and suggest that neurotransmitter(s) can coordinate trophic influences on different cell populations.

Cellular localization and laminar distribution of NMDAR1 mRNA in the rat cerebral cortex.

N-methyl-D-aspartate (NMDA) receptors, which play a critical role in many cortical functions, are composed of a heteromeric assembly of different subunits: of these, the NMDA receptor subunit 1 (NMDAR1) is a constant component of, and thus an excellent marker for, NMDA receptors. In this study, we have investigated the cellular localization and laminar distribution of NMDAR1 mRNA in the cerebral cortex of adult rats by in situ hybridization histochemistry with a 35S-labeled cRNA probe. Specificity and background levels were determined in adjacent sections incubated with a 35S-labeled sense RNA. In sections incubated with the antisense RNA probe, specific hybridization signal was observed in a large number of cells. Some cells, however, did not appear to contain NMDAR1 mRNA. The vast majority of these unlabeled cells were small, suggesting that they are astrocytes or other small nonneuronal cells. Double-labeling studies with in situ hybridization histochemistry and immunocytochemistry with antibodies to glial fibrillary acidic protein (GFAP) showed that about 95.7% of the GFAP-positive cells did not express NMDAR1 mRNA, indicating that virtually all astrocytes do not contain this transcript. A semiquantitative evaluation of cortical neurons, defined as those cells larger than the GFAP-positive astrocytes, revealed that about 80% were associated with silver grains. The number of silver grains associated with every neuron was determined from sections exposed for 15 days, the background level was subtracted, and all labeled neurons were grouped into five groups: A (< or = 10 grains), B (11-20 grains), C (21-30 grains), D (31-40 grains), and E (> 40 grains). The number of neurons belonging to each group was then evaluated according to their occurrence in each cortical layer. In layer I all labeled neurons were in group A, whereas in layers II-III and V-VI positive neurons were in group A-E. In layer IV most neurons were in groups A and B, whereas only a few were in group E. These observations indicate that 1) virtually all cortical cells containing NMDAR1 mRNA in adult rats are neurons; 2) about 80% of all cortical neurons express NMDAR1 mRNA; and 3) labeled neurons can be divided into several groups on the basis of NMDAR1 mRNA levels expressed, which presumably reflect the number of NMDA receptors. The existence of neurons with a different number of receptors may be a critical factor for determining the physiological effect of NMDA receptor activation.(ABSTRACT TRUNCATED AT 400 WORDS)

Interleukin-1 beta mRNA expression in ischemic rat cortex.

Interleukin-1 beta is a proinflammatory cytokine produced by blood-borne and resident brain inflammatory cells. The present study was conducted to determine if interleukin-1 beta mRNA was produced in the brain of rats subjected to permanent focal ischemia. Rat interleukin-1 beta cDNA, synthesized from stimulated rat peritoneal macrophage RNA by reverse transcription and polymerase chain reaction and cloned in plasmid Bluescript KS+, was used to evaluate the expression of interleukin-1 beta mRNA in cerebral cortex from spontaneously hypertensive rats and normotensive rats subjected to permanent middle cerebral artery occlusion. Interleukin-1 beta mRNA was quantified by Northern blot analysis and compared with rat macrophage RNA standard. To correct for gel loading, blots were also analyzed with cyclophilin cDNA, which encodes an abundant, conserved protein that was unchanged by the experimental conditions. Interleukin-1 beta mRNA produced in the ischemic zone was significantly increased from 6 hours to 120 hours, with a maximum of 211 +/- 24% of interleukin-1 beta reference standard, ie, 0.2 ng stimulated rat macrophage RNA, mRNA compared with the level in nonischemic cortices (4 +/- 2%) at 12 hours after ischemia (P < .01; n = 6). Interleukin-1 beta mRNA at 12 hours after ischemia was markedly elevated in hypertensive rats over levels found in two normotensive rat strains. Neurological deficits were also apparent only in the hypertensive rats. Brain interleukin-1 beta mRNA is elevated acutely after permanent focal ischemia and especially in hypertensive rats. These data suggest that this potent proinflammatory and procoagulant cytokine might have a role in brain damage following ischemia.

Amygdala kindling potentiates seizure-stimulated immediate-early gene expression in rat cerebral cortex.

Kindling induces long-term adaptations in neuronal function that lead to a decreased threshold for induction of seizures. In the present study, the influence of amygdala kindling on levels of mRNA for the immediate-early genes (IEGs) c-fos, c-jun, and NGF1-A were examined both before and after an acute electroconvulsive seizure (ECS). Although amygdala kindling did not significantly influence resting levels of c-fos mRNA in cerebral cortex, ECS-stimulated levels of c-fos mRNA (examined 45 min after ECS) were approximately twofold greater in the cerebral cortex of kindled rats relative to sham-treated controls. The influence of kindling on IEG expression was dependent on the time course of kindling, as ECS-stimulated levels of c-fos mRNA were not significantly increased in stage 2 kindled animals. ECS-stimulated levels of c-jun and NGF1-A mRNA were also significantly increased in cerebral cortex of kindled rats relative to sham-treated controls. The influence of kindling on IEG expression was long-lasting because an acute ECS stimulus significantly elevated levels of c-fos and c-jun mRNA in the cerebral cortex of animals that were kindled 5 months previously. In contrast to these effects in cerebral cortex, kindling did not influence ECS-stimulated levels of c-fos mRNA in hippocampus. Finally, immunohistochemical studies revealed lamina-specific changes in the cerebral cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of c-fos mRNA in cerebral cortex by excitotoxin stimulation of cortical inputs: involvement ofN-methyl-d-aspartate receptors

In this study we have characterized the induction of c-fos mRNA in cerebral cortex in response to unilateral kainate injection into the nucleus basalis. This treatment is associated with an intense stimulation of the ascending pathway and the subsequent induction of ornithine decarboxylase (ODC) enzyme activity and ODC mRNA in ipsilateral cerebral cortex which is sensitive to treatment with MK-801 and dihydropyridine antagonists. Unilateral injection of kainate into nucleus basalis caused a marked induction of c-fos mRNA in ipsilateral cortex which was detectable at 1 h, reached a maximal value at 8 h where c-fos mRNA levels were 16 times those in unoperated animals and then returned to control values by 24 h. However, the early induction of c-fos mRNA at 1 h was not related to a specific effect of kainate since at this time point, sham-operated animals also showed a significant increase in the level of c-fos mRNA in ipsilateral cerebral cortex. No significant induction of c-fos mRNA was detected in ipsilateral cortex in sham-operated animals at 4 and 8 h after injection of vehicle. Treatment with the N-methyl-D-aspartate (NMDA) receptor antagonist, MK-801 (3 mg/kg) significantly attenuated the response obtained at 4 h and 8 h after kainate injection by 73% and 55% respectively, but did not influence the level of c-fos mRNA induced at 1 h. Delaying administration of MK-801 by 30 min reduced the effectiveness of this treatment on the response obtained at 4 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Excitotoxin lesion of nucleus basalis causes a specific decrease in Go mRNA in cerebral cortex: Sensitivity to MK-801

Lesions of the ascending cholinergic pathway from nucleus basalis are known to have profound effects on cortical function. In particular, a substantial potentiation of carbachol-stimulated polyphosphoinositide turnover is detected from 1 day after lesion and is maintained for several days before returning to normal by 1 month. In this study the effect of this lesion was investigated on levels of three G-protein α-subunit mRNAs. Excitotoxin lesion of the nucleus basalis caused a selective reduction in the levels of Goα mRNA in cerebral cortex ipsilateral to the lesion, G5α and Giα mRNA being unaffected. The maximal effect was obtained at 3 days after lesion where levels of Goα mRNA were decreased by 40% compared to sham-operated animals. Levels of Goα mRNA returned to normal values by 28 days. Treatment with MK-801 caused a significant attenuation of the decrease in Goα mRNA, indicating the involvement of NMDA receptors in this response.

Patterns of cerebral cortex mRNA expression

A pool of 163 clones, isolated by screening 60,000 members of a Macaca fascicularis cerebral cortex cDNA library with a cortex-minus-cerebellum subtracted probe prepared by the phenol enhancement method, was analyzed by Northern blot hybridization studies. One hundred fifty-three of these clones corresponded to 22 RNAs whose abundance was at least 2-fold higher in cerebral cortex poly(A)+ RNA samples than in samples of cerebellar poly(A)+ RNA. Seven of these RNAs, represented by 131 clones, were undetectable in cerebellum. Only 10 of the 163 clones proved to be false positives. The abundance of several of these cortex-enriched RNAs was altered in Alzheimer's disease brains. Several RNAs that were present in cerebral cortex but undetectable in cerebellum were generally enriched in telencephalon, although none was restricted to the cortex. One of the cortex enriched RNAs, whose nucleotide sequence is presented, encoded monkey preprocholecystokinin. Overall, this study provides insights into the powers and limitations of subtractive hybridization and into the patterns of gene expression in the central nervous system.

Induction of ornithine decarboxylase mRNA in cerebral cortex in response to lesion of nucleus basalis

Induction of ornithine decarboxylase mRNA in cerebral cortex in response to lesion of nucleus basalis