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PubMed1993

Differential expression of mRNAs encoding gamma and delta subunits of Ca2+/calmodulin-dependent protein kinase type II (CaM kinase II) in the mature and postnatally developing rat brain.

The expression of mRNAs encoding gamma and delta subunits of Ca2+/calmodulin-dependent protein kinase type II (CaM kinase II) in the brain of mature and postnatally developing rats was examined by in situ hybridization histochemistry. At the adult stage, mRNAs for both subunits were expressed in the olfactory bulb, and piriform cortex. The cerebral neocortex expressed the gamma subunit mRNA evenly through the layers II to VI at a moderate level, whereas the delta subunit mRNA was expressed in a distinctly laminar distribution. The hippocampal pyramidal and dentate granule cells expressed the gamma subunit mRNA intensely without any significant expression signals for the delta subunit. In the cerebellum, moderate expression signals for the gamma subunit were confined to the Purkinje cell layer, while intense expression signals for the delta subunit were detected in the cerebellar granule cell layer, without any significant expression signals in the Purkinje cell layer. In the spinal cord, mRNA for the gamma subunit was expressed in neurons throughout the gray matter, while the expression of mRNA for the delta subunit was confined to neurons in laminae I and IX. The expression pattern of genes for both subunits was basically accomplished at birth with lower intensity, except for the striatum and cerebellar Purkinje cells, which transiently expressed mRNA for the gamma and delta subunits, respectively, at birth. These results indicate that the expression of genes for each of the subunits of CaM kinase II is differentially regulated in various brain regions and that the individual subunits are involved in differential functions in mature and developing rat brain.

Animals↗
PubMed1993

In situ hybridization study of interleukin-1 beta mRNA induced by kainic acid in the rat brain.

The distribution patterns of interleukin-1 beta (IL-1 beta) mRNA in various brain regions of saline- and kainic acid-treated rats were examined using in situ hybridization technique. In normal rat brain, the signals of IL-1 beta mRNA were observed in the cerebellar Purkinje cells and in dispersed cells in the hypothalamus. In the case of the kainic acid treatment, IL-1 beta mRNA was intensely induced in the olfactory bulb, lateral septum, thalamus, hypothalamus, polymorphic layers of hippocampus, piriform cortex, amygdala, entorhinal cortex and cerebral cortex at 2 h after the injection of kainic acid. In the hypothalamic region, we observed the induction of IL-1 beta mRNA around the paraventricular hypothalamic nucleus, anterior hypothalamic area, dorsomedial and ventromedial hypothalamic nucleus, mammillary regions and arcuate nucleus. The signal of IL-1 beta mRNA was still expressed 4 h after treatment with kainic acid, less intensely than at 2 h, but above the control level. In these regions, IL-1 beta mRNA was expressed mainly in the glial cells, which were densely stained by Cresyl violet and did not contain glial fibrillary acidic protein. These results suggest that IL-1 beta is produced by a certain type of glial cells, maybe microglia, and might have regulatory functions in the central nervous system.

Animals↗
PubMed1993

Barrel rotation evoked by intracerebroventricular injection of somatostatin and arginine-vasopressin is accompanied by the induction of c-fos gene expression in the granular cells of rat cerebellum.

Intracerebroventricular (i.c.v.) injection of somatostatin (SS) or arginine-vasopressin (AVP) elicits barrel rotation (BR) in rats. To identify the potential neuron structures involved in this characteristic behavior, the regional expression of the c-fos gene in rat brain after i.c.v. injection of SS (10 micrograms) or AVP (1 micrograms) was examined by hybridization histochemistry. The c-fos expression could serve as a marker of neuronal activity and/or neural transmission. Following SS-induced BR, c-fos gene expression was observed in the lingula, uvula, nodulus, simplex, centralis, and culmen of the cerebellum, while following AVP-induced BR, c-fos gene expression was observed in the first four of the above-mentioned regions of the cerebellum, but not in the centralis or culmen. In these regions, the c-fos mRNA signals were observed on the granular layer. Expression of the c-fos gene was immediately and transiently induced and was not observed in rats in which BR was not evoked after SS or AVP injection. In both control rats and SS- or AVP-injected rats, the c-fos gene expression was induced in the piriform cortex and the flocculus of the cerebellum. The findings suggest that BR is a manifestation of behavior induced by massive transsynaptic activation of the granular cells in the cerebellum.

Animals↗
PubMed1995

The angiotensin receptor subtype AT1A predominates in rat forebrain areas involved in blood pressure, body fluid homeostasis and neuroendocrine control.

Subtypes of the angiotensin II (Ang II) type-1 (AT1) receptor are probably involved in distinct actions of the peptide, since their distribution in peripheral organs and regulation of their gene expression are different. We investigated the distribution of AT1A and AT1B receptor subtype mRNAs in the rat forebrain and pituitary using sensitive cRNA probes for in situ hybridization. High level of AT1A receptor mRNA expression is observed in the subfornical organ (SFO) and in the anterior hypothalamus, particularly the periventricular tissue surrounding the anterior portion of the 3rd ventricle (AV3V), which contains the organum vasculosum of the lamina terminalis (OVLT), the median preoptic nucleus and the preoptic periventricular nucleus as well as in the hypothalamic periventricular nucleus and in the parvocellular part of the paraventricular nucleus (PVN). Moderate to strong AT1A labeling was found in the anterior olfactory nucleus, the piriform cortex and the nucleus of the lateral olfactory tract. Very low AT1B receptor mRNA expression was found in the SFO and the PVN. In contrast, strong AT1B receptor mRNA expression coincided with low AT1A receptor mRNA expression in the anterior pituitary. Labeling was cytoplasmic at the light microscopic level. We thus suggest that the AT1A receptor is responsible for the central actions of Ang II in the rat forebrain whereas direct actions of Ang II on the anterior pituitary are mediated by the AT1B receptor subtype.

Animals↗
PubMed1994

Localization of mRNA for protein phosphatase 2A in the brain of adult rats.

The gene expression for alpha and beta isoforms of type 2A protein phosphatase (PP2A-alpha and -beta) in the adult rat brain was examined by in situ hybridization analysis. No marked difference in the gene expression was discerned between the two isoforms in large portions of brain, except for the thalami in which the expression level for the alpha isoform was similar to that in the cerebral neocortex whereas that for the beta was lower than that in the neocortex. The gene expression was observed intensely in the piriform cortex, the cerebellar Purkinje and granule cell layers, and the hippocampal pyramidal and dentate granule cell layers, and the locus ceruleus, whereas the moderate levels of its expression were observed in the olfactory mitral cells and the pontine nuclei. The cerebral neocortex expressed the mRNA moderately to weakly without any laminar patterns, whereas the expression level in the caudate-putamen was very low. This expression pattern is basically similar to that of PP2C reported previously, except for the plexus choroideus and ependyma having no significant expression for PP2A.

Animals↗
PubMed1994

Cloning and expression of a neural differentiation-associated gene, p205, in the embryonal carcinoma cell line P19 and in the developing mouse.

Mouse P19 embryonal carcinoma cells can be reproducibly differentiated into neurons and glial cells upon treatment with high concentration of retinoic acid (RA). In order to understand the molecular mechanisms that control early neural differentiation, we screened a cDNA library made from 24-h RA-treated P19 cells with subtracted cDNA probes. One clone was positive in the secondary screening and was designated as p205. This clone (1.1 kb) has an open reading frame of 317 amino acids with homology to G-protein beta subunit. This protein sequence was identical to chicken and human genes previously identified as a major histocompatibility complex-associated gene. The complete conservation of its amino acid sequence between mouse, human and chicken provides strong evidence that the p205 protein fulfills a fundamental function. Developmental Northern blot analysis revealed that a p205 mRNA is expressed at high levels in the embryonic mouse brain, decreasing as development proceeds. In situ hybridization revealed that p205 mRNA is strongly and ubiquitously expressed in the embryonic and early postnatal mouse brain. This expression decreased during postnatal development and was localized in the dentate gyrus, habenula, piriform cortex, paraventricular nucleus of the hypothalamus and supraoptic nucleus of the adult brain. These results suggest that this protein plays an important role in the developing brain and neuronal differentiation.

Aging↗
PubMed1994

High induction threshold for transcription factor KROX-20 in the rat brain: partial co-expression with heat shock protein 70 following limbic seizures.

The transcription factor KROX-20, unlike many other immediate early genes, is not expressed in the rat hippocampus after bicuculline induced generalized seizures. Since limbic seizures are a more injurious stimulus, the KROX-20 expression profile was investigated in adult rats subjected to kainic acid induced limbic epilepsy at postictal intervals up to 48 h. Immunocytochemistry was performed using a specific polyclonal antiserum. In the hippocampus a sequential induction was observed with peak levels attained in dentate gyrus at 3 h, in CA1 at 8 h and in CA3 between 8 and 24 h, respectively. In contrast, no KROX-20 induction was found in hilus neurons. Prominent neuronal KROX-20 induction was also detected in other areas of the limbic system, in particular in amygdala and piriform cortex, as well as non-limbic regions such as neocortex and striatum. As is the case with KROX-20, heat shock protein (HSP) 70, a reliable marker for reversible neuronal injury, has a high induction threshold. Though not inducible in the hippocampus by generalized seizures, it is expressed after limbic epilepsy. Therefore, co-expression of KROX-20 and HSP70 was studied by a double labeling technique using a monoclonal antibody directed against the inducible form of HSP70. Neuronal subpopulations with perfect co-expression such as hippocampal CA1 neurons contrasted with others demonstrating partial co-induction (cortical neurons) or lack of co-expression (hilus cells), indicating that different stimuli trigger the activation of these two inducible genes.

Animals↗
PubMed1994

Localization and age-dependent expression of hexokinase mRNA in the rat brain.

Localization of mRNA encoding for the enzyme hexokinase and its regulation in aged animals was carried out in rat brain using the in situ hybridization technique. The highest levels of the hybridization signal were observed in the olfactory bulb, piriform cortex, tenia tecta, hippocampus and granular cells of the cerebellum. Other brain areas and nuclei including cerebral cortex, thalamus, hypothalamus, substantia nigra, subiculum, choroid plexus and superior colliculus displayed moderate to low density of transcripts. Correlation between relative hexokinase content and levels of its mRNA was found only for some brain regions such as caudate-putamen, geniculate nucleus, ventral and lateral thalamic nuclei, superior colliculus and granular cells of the cerebellum. In the cerebral cortex and hippocampus of old animals the expression of hexokinase was significantly increased at 18 and 24 months of age. From the present data we conclude that although hexokinase is an ubiquitous enzyme, sites of synthesis display a discrete and uneven localization in rat CNS and expression, in the aging brain, might be regulated to compensate for reduced oxidative phosphorylation in the brain tissue.

Aging↗
PubMed1994

Localization of phosphatase inhibitor-1 mRNA in the developing and adult rat brain in comparison with that of protein phosphatase-1 mRNAs.

The localization and ontogenic changes in the gene expression for phosphatase inhibitor-1 (I-1) were analyzed by in situ hybridization histochemistry, and they were compared with those for three catalytic subunits of protein phosphatase type 1 (PP-1). At the adult stage, intense expression signals for I-1 were detected in the hippocampal formation, piriform cortex, claustrum, dorsal endopiriform cortex, suprachiasmatic nucleus, choroid plexus, arachnoid membrane, and pineal body. Moderate expression signals for I-1 were observed in the olfactory neuronal layers, caudate putamen, layers II-IV, and VI of the neocortex, and cerebellar granule cells, whereas the expression levels were low in the thalamus, cerebellar Purkinje cells, and brain stem nuclei. Although the expression levels for the three PP-1 mRNAs varied notably in various brain regions, a relatively high and parallel expression of I-1 and PP-1 mRNAs was found in most regions of the forebrain. However, the dissociation in the expression levels between I-1 and PP-1 mRNAs was found in several loci: the laminar expression of I-1 mRNA versus the homogeneous expression of PP-1 mRNAs in the cerebral cortex; low levels of expression of I-1 mRNA versus relatively high expression of PP-1 mRNAs in the brain stem nuclei; high expression of I-1 mRNA in the arachnoid membrane versus low expression of PP-1 mRNAs in it. The unparallel expression was also seen in embryonic brain: No significant expression of I-1 mRNA versus substantial expression of PP-1 mRNAs in the ventricular zone and cerebellar external granular layer; transiently high expression of I-1 mRNA in developing thalamus versus constantly moderate to low expression of PP-1 mRNAs there. These findings suggest that I-1 may play some discrete roles independent of the regulation of PP-1 in certain regions and developing stages of the brain.

Animals↗
PubMed1995

Decreased expression of the alpha subunit of Ca2+/ calmodulin-dependent protein kinase type II mRNA in the adult rat CNS following recurrent limbic seizures.

Calcium/calmodulin-dependent protein kinase type II (CamKII) is a ubiquitous brain enzyme implicated in a wide variety of neuronal processes. Understanding CamKII has become increasingly complicated with the recent identification of multiple gene transcripts coding for separate subunits. Previous studies have shown that mRNA for the alpha subunit of CamKII can be increased by reduction of afferent input. In this study we have examined the regulation of alpha CamKII mRNA following increased activity due to seizures. Using in situ hybridization with a cRNA probe against the rat alpha CamKII sequence we found reduced levels of hybridization following limbic seizures induced by lesions of the hilus of the dentate gyrus. Hybridization was most dramatically reduced in the granule cells of the dentate gyrus and the pyramidal cells of hippocampal region CA1. There were also significant reductions in hybridization in the superficial layers of neocortex and piriform cortex. In each of these region hybridization was decreased in the molecular layers which is consistent with the reported dendritic localization of alpha CamKII mRNA. All changes in mRNA content were transient, with maximal reductions at 24 h following lesion placement and a return to control levels by 96 h. These findings demonstrate the negative regulation of alpha CamKII mRNA by seizure activity and raise the possibility that synthesis of this kinase may be regulated by normal physiological activity.

Animals↗
PubMed1996

Distribution of the mRNA for protein phosphatase T in rat brain.

We have recently cloned a novel protein serine/threonine phosphatase (PPT) from rat mRNA which is predominantly expressed in the brain (Becker et al., J. Biol. Chem., 269 (1994) 22586-22592). In the present study, the regional distribution of PPT mRNA in the brain of adult rats was characterized by in situ hybridization histochemistry. PPT mRNA was found to be differentially expressed throughout the rat brain. Highest transcript levels were found in specific neuronal populations (hippocampus, piriform cortex, taenia tecta, medial habenula, granular cell layer of the cerebellum) as well as in the choroid plexus of the third and lateral ventricles. In contrast, expression levels in some brain areas, e.g., caudate putamen and white matter, were beyond the detection limit of in situ hybridization. The pattern of expression of PPT in rat brain differs from that of other protein serine/threonine phosphatases and may reflect specific functions of this phosphatase.

Animals↗
PubMed1996

Temporal-spatial pattern of c-Fos expression in the rat brain in response to indispensable amino acid deficiency. II. The learned taste aversion.

Rats rapidly become anorectic when eating an amino acid-imbalanced diet that induces a deficiency of an indispensable amino acid. Recognition of amino acid deficiency is thought to be a function of the anterior piriform cortex. However, the neuronal circuitry underlying the secondary learned aversion to such diets may involve the amygdala. In this study, Fos immunohistochemistry was employed to identify regions of the brain activated during the learned aversion phase of the response to an amino acid-imbalanced diet. c-Fos expression was examined in the brains of rats at intervals from 1 to 6 h after introduction of a diet imbalanced in threonine, a corrected (amino acid-balanced) diet or a basal (low protein) diet. The study has revealed that, within the time frame associated with the learned aversive response, Fos-immunoreactive (Fos-IR) neurons increased selectively in the central nucleus of the amygdala in animals fed a threonine-imbalanced diet. These results suggest a temporal relationship between changes in neuronal activity in the central nucleus of the amygdala and the learned aversion associated with acute amino acid deficiency.

Amygdala↗
PubMed1996

Two synaptotagmin genes, Syt1 and Syt4, are differentially regulated in adult brain and during postnatal development following kainic acid-induced seizures.

The synaptotagmins together with other vesicle proteins are thought to be essential for the docking and/or fusion of synaptic vesicles with the plasma membrane that occurs following depolarization and calcium influx in presynatic terminals. Syt4, the fourth identified member of the synaptotagmin family, is inducible in PC12 cells by depolarization and secretagogues, and in limbic regions of the adult rat brain by kainic acid-induced seizures. In the present study, we examined the time course of the seizure-induced changes in the expression of Syt4 and Syt1, both in adult animals and during the postnatal period. Syt4 was transiently induced in several structures of the adult rat brain following seizure activity with peak inductions between 4 and 8 h and overal return to control values by 30 h. No induction was observed following seizure activity in 7-day-old animals. The brain regions most sensitive to increased induction were, in decreasing order of sensitivity, hippocampal pyramidal cells dentate granule cells and piriform cortex pyramidal cells. The brain areas showing the greatest Syt4 stimulation in adults were also the areas in which Syt4 was induced by seizures earlier in development. In contrast, Syt1 mRNA was depressed in adult brains following seizure activity, particularly in the dentate granule cells. Our results suggest that the differential regulation of different synaptotagmin genes following excessive neuronal activity might participate in rapid adaptation of subsequent transmitter release.

Animals↗
PubMed1995

Temporalspatial patterns of expression of metallothionein-I and -III and other stress related genes in rat brain after kainic acid-induced seizures.

Kainic acid-induced seizures in the rat brain cause severe brain damage that is thought to result, in part, from oxidative stress. In this study, we examine the consequences of systemic administration of kainic acid on expression of several genes that encode proteins thought to play roles in protection from oxidative stress, including metallothionein-I, and -III. Kainic acid causes an increase in metallothionein-I and heme oxygenase-I mRNAs, as well as an increase in c-fos, heat shock protein-70, and interleukin-1 beta mRNAs. The induction of these mRNAs is seizure dependent, and is greater in brain areas with extensive damage (e.g. piriform cortex) than in areas with minimal damage (e.g. frontal cortex and cerebellum). In contrast, little or no change in mRNA for metallothionein-III, manganese superoxide dismutase, copper-zinc superoxide dismutase, glutathione-s-transferase ya subunit or glutathione peroxidase occur. The prolonged and robust concordant induction of the metallothionein-I and heme oxygenase-I genes may reflect the oxidative stress produced by kainic acid-induced seizures. In addition, the induction of interleukin-1 beta gene expression suggests an inflammatory response in brain regions damaged by kainic acid-induced seizures. Delineating the regulation of genes associated with oxidative and inflammatory responses can contribute to a fuller understanding of seizures and associated brain damage.

Animals↗
PubMedDate not supplied

Mutant and native human beta-amyloid precursor proteins in transgenic mouse brain.

Human beta-amyloid precursor protein (beta APP) has been targeted to transgenic neurons using synapsin I promoter-based chimeric transgenes. Native human beta APP was introduced as well as beta APP containing mutations genetically linked to familial Alzheimer's disease (AD) and to hereditary cerebral hemorrhage with amyloidosis-Dutch type. In mouse brain, human beta APP RNA was up to 60% as abundant as total endogenous beta APP RNA. Human beta APP gene expression was most abundant in the CA subfields of the hippocampus and in the piriform cortex. Correct processing of human beta APP at the beta-secretase cleavage site was demonstrated in transgenic mouse brains. Despite a 40% increase in total beta APP immunoreactivity in lines expressing mutant human beta APP, no evidence of amyloid deposition was found in brains of mice up to 14 months in age. Higher levels of mutant human beta APP, increased age, or other factors may be necessary to elicit beta-amyloid-related neuropathologies in the rodent brain.

Amyloid beta-Protein Precursor↗
PubMed1981

Interamygdaloid connections in the rat studied by the horseradish peroxidase method.

Neurons of the rat amygdaloid body were labeled with horseradish peroxidase following its injection into contralateral nuclei of the amygdala. The results strongly suggest that there is a contralateral amygdaloid projection from the basal (dorsal and ventral) nuclei of amygdala; it terminates in the medial, central and lateral nucleus. True commissural connections were found only between posterior parts of the cortical nuclei of amygdala and between homonymous areas of the piriform cortex.

Amygdala↗
PubMed1985

Limbic, hypothalamic, cortical and spinal regions are enriched in receptors for thyrotropin-releasing hormone: evidence from [3H]ultrofilm autoradiography and correlation with central effects of the tripeptide in rat brain.

Light microscopic autoradiographic localization of specific recognition sites for thyrotropin-releasing hormone (TRH) was determined on thin sections of rat brain using the potent analogue [3H](3-Me-His2)-TRH ([3H]MeTRH). Microdensitometric analysis of the relative optical densities of TRH receptor labelling revealed the following brain regional enrichment: lateral and cortical amygdaloid nuclei greater than ventral dentate gyrus greater than n. accumbens greater than medial septum greater than piriform cortex greater than paraventricular thalamic and hypothalamic nuclei greater than preoptic area greater than diagonal band of Broca greater than lateral septum greater than I-IV layers of frontoparietal cortex greater than dorsal hippocampus greater than olfactory tubercle greater than caudate putamen; globus pallidus. In the spinal cord the apparent relative enrichment of TRH receptors was: substantia gelatinosa = central canal gray greater than ventral gray greater than dorsal gray (layers III-VII) greater than white matter. This heterogeneous distribution of TRH binding sites correlated well with our previous data obtained from membrane binding studies. Furthermore, the specific anatomical localization of receptors for TRH in many nuclei was consistent with those loci involved in the mediation of many physiological and behavioural actions of the peptide in rodent brain.

Animals↗
PubMed1986

Origin of the neuropeptide Y innervation of the rat retrohippocampal region.

Using the method of retrograde tracing of Fast Blue in combination with immunohistochemistry, the origins of the retrohippocampal neuropeptide Y (NPY) innervation was studied in the rat brain. The findings suggest that two NPY-immunoreactive (NPY-i) afferent systems, one intrinsic and the other of extrinsic origin give rise to the massive NPY innervation of the retrohippocampal region, including the entorhinal area (EA). The intrinsic projections originate from multipolar and fusiform cells situated primarily in layers IV through VI of the medial and lateral EA, as well as from a small number of NPY-i basket cells situated in layer II. Other NPY-i afferents originate from cortical neurons with long association projections located in the deep layers of the perirhinal area and in the piriform cortex, as well as from cells situated throughout the rostrocaudal extent of the endopiriform nucleus, in the lateral nucleus of amygdala and in the nucleus locus coeruleus.

Amidines↗