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At least 163 records · Page 9Linked to original sources
PubMed1984

Upgaze paralysis caused by lesion of the periaqueductal gray matter.

A 61-year-old man with upgaze paralysis was found on postmortem examination to have had a single lesion of the brain stem confined to the periaqueductal gray matter between the levels of the superior and inferior colliculi. Most previous neuropathologic cases reported in human beings have consisted of much larger lesions with common involvement of the posterior commissure and pretectum. We suggest that the lesion in this case caused upgaze paralysis either by interrupting descending fibers from the interstitial nucleus of Cajal or by destroying neurons located within the periaqueductal gray matter.

Brain Diseases↗
PubMed1991

Absence of magnetic resonance imaging evidence of pontine abnormality in infantile autism.

In vivo studies involving magnetic resonance imaging and studies of neuropathologic specimens have shown that autism is most consistently associated with developmental hypoplasia of the neocerebellum. We investigated whether the cerebellar hypoplasia was accompanied by gross structural abnormalities in the major input (cerebrocerebellar) and output (cerebrorubral) pathways to the cerebellum by measuring the area of the ventral pons (including the pontine nuclei and the transverse fibers) and the midbrain on midsagittal magnetic resonance images in 34 autistic and 44 subjects. The area of the entire pons and several regions of interest within the midbrain (including the superior and inferior colliculi) were also determined with midsagittal magnetic resonance images. We found no significant difference between measurements of the pons and midbrain in autistic and control subjects. Our data show no evidence of gross anatomic abnormalities in the input and output pathways to the cerebellum in autism, a finding that is consistent with previous studies of neuropathologic specimens; rather, the reduced size of the neocerebellum in autism appears to be the result of maldevelopment within the cerebellum itself.

Adolescent↗
PubMed1999

Colocalization of androgen receptors and mating-induced FOS immunoreactivity in neurons that project to the central tegmental field in male rats.

Bilateral lesions of the central tegmental field (CTF) in male rats virtually eliminate mating behavior. This study examined if mating-induced Fos expression (a measure of neuronal activation) and androgen receptors (AR) are colocalized in brain and spinal cord neurons which project to the CTF. Animals received unilateral injections of the retrograde tracer Fluorogold (FG) in the lateral part of the CTF (CTFl), and 10 days later were killed after ejaculating with females. Brains and spinal cords were examined for FG transport, AR-immunoreactivity (AR-ir), and Fos-immunoreactivity (Fos-ir). AR-ir and Fos-ir were visualized with fluorescence microscopy using cyanine-conjugated and fluorescein-conjugated secondary antibodies. The CTFl received projections from AR-containing neurons in forebrain structures (bed nucleus of stria terminalis, medial preoptic area, lateral and ventromedial hypothalamus), in the central amygdala and various mid- and hindbrain structures (dorsolateral tegmentum, superior and inferior colliculi, pedunculopontine nucleus), and in the lumbosacral spinal cord (lamina X). Some of the AR-containing neurons in bed nucleus of stria terminalis and in the dorsal part of the medial preoptic area with projections to the CTFl were activated by mating. Most AR-containing neurons in spinal lamina X with projections to the CTFl were also activated by mating. Information from spinal cord and pontine nuclei and from outputs descending from the forebrain may be relayed in the CTFl. Thus, as part of a network of hormone-sensitive neurons linking brain and spinal cord mechanisms for mating, the CTFl could participate in the integration of visceral and somatic information relevant for sexual behavior.

Animals↗
PubMed1999

Preprotachykinin-A mRNA expression in the human and monkey brain: An in situ hybridization study.

The mRNA expression for preprotachykinin-A (PPT-A) was studied throughout the human and cynomolgus monkey brain to assess the neuroanatomical expression pattern of the PPT-A gene in primates. In situ hybridization showed that the PPT-A mRNA is expressed highly in specific regions of the postmortem human brain, including the striatum, islands of Calleja, hypothalamus (posterior, premammillary, medial mammillary, and ventromedial nuclei), superior and inferior colliculi, periaqueductal gray, and oculomotor nuclear complex. PPT-A mRNA-expressing neurons also were present in the paranigralis (ventral tegmental area) and were scattered in the bed nucleus stria terminalis throughout the sublenticular substantia innominata region, including the diagonal band of Broca and the nucleus basalis of Meynert. In the hippocampus, high PPT-A mRNA expression was localized predominantly to the polymorphic layer of the dentate gyrus; no labeled cells were present in the granular layer. Positively labeled cells also were found scattered in the CA regions as well as in the amygdaloid complex. Neocortical expression of PPT-A mRNA was localized mainly to the deep laminae (layers V/VI), except for the striate cortex (labeling was seen also in superficial layers). The subiculum, thalamus, globus pallidus, ventral pallidum, substantia nigra pars compacta, red nucleus, pontine nuclei, and cerebellum were characterized by very weak to undetectable expression of PPT-A mRNA. An expression pattern was evident in the monkey forebrain similar to that observed in the human, except for the absence of PPT mRNA-expressing cells in the medial mammillary nucleus despite intense expression in supramammillary, lateral mammillary, and premammillary nuclei. Overall, more similarities than differences are apparent between primate species in the expression pattern of the PPT-A gene. J. Comp. Neurol. 411;56-72, 1999.

Adult↗
PubMed1998

Regional activation of L-type voltage-sensitive calcium channels in experimental thiamine deficiency.

During pyrithiamine-induced thiamine deficiency (PTD), specific regions of the brain develop histological damage. The basis of this selective vulnerability is unknown but the mechanism may involve a glutamate-mediated excitotoxic process in affected structures, leading to alterations in membrane potential and disturbances in calcium homeostasis. In this study, we have examined the volume of distribution of [3H]nimodipine, an L-type voltage-sensitive calcium channel (VSCC) antagonist, in the brain of the PTD rat. An increase in specific binding of [3H]nimodipine was detected only in the posterior thalamus at the symptomatic stage, immediately following the loss of righting reflexes (P < 0.0001). There was also an increase in nonspecific binding in the medial geniculate and inferior colliculi. Replenishment with thiamine at the symptomatic stage returned [3H]nimodipine binding to normal levels. These findings provide evidence that depolarization and activation of L-type VSCCs occur in the posterior thalamus and may contribute to the appearance of histological lesions in this structure during experimental thiamine deficiency.

Animals↗
PubMed1999

Manganese uptake into rat brain during development and aging.

Manganese (Mn) is an essential metal and plays an important role in the brain. To evaluate Mn uptake into the brain during development and aging, 54Mn concentrations in the brain of rats aged from 5 days to 95 weeks were measured after injection of 54MnCl2. 54Mn concentration in the brain of 5-day-old rats was the highest of all age groups tested. The liver and blood of 5-day-old rats also showed the highest 54Mn concentrations among the age groups. These results suggest that Mn is required in a high amount during infancy and that a sufficient Mn supply is critical for normal brain development. The high uptake of Mn into the brain of neonatal rats may be due to high levels of Mn in the blood, which may be supplied from the liver. In the 5-day-old brain, 54Mn was relatively concentrated in the hippocampal CA3 and dentate gyrus and the pons. In the aging brain, 54Mn was relatively concentrated in the inferior colliculi, olivary nuclei and red nuclei.

Aging↗
PubMed2000

Influence of transferrin on manganese uptake in rat brain.

To evaluate the influence of transferrin (Tf) on manganese (Mn) uptake in the brain, pH 8.6 buffer-treated (54)MnCl(2), which has a higher affinity for Tf than untreated (54)MnCl(2), and Tf-bound (54)Mn were prepared. When pH 8.6 buffer-treated (54)MnCl(2) and untreated (54)MnCl(2) were incubated with apo-Tf in Tris (2-amino-2-hydroxymethylpropane-1,3-diol)-HCl buffer, the percentage of the total (54)MnCl(2) bound to Tf was approximately 85% and 10%, respectively. One hour after intravenous (iv) injection of pH 8.6 buffer-treated (54)MnCl(2) and untreated (54)MnCl(2), both tracers were concentrated similarly in the choroid plexus in the ventricles and distributed in other brain regions. Six days after iv injection, both pH 8.6 buffer-treated (54)MnCl(2) and untreated (54)MnCl(2) tracers were concentrated in the superior olivary complex, inferior colliculi, and red nuclei, although the former radioactivity was lower than the latter. Moreover, Tf-bound (54)Mn was prepared and injected iv into rats. The radioactivity from Tf-bound (54)Mn, which was also concentrated in the same regions, e.g., the superior olivary complex, was the lowest of all three traces. Tf-bound (54)Mn was stable during incubation with serum for 1 hr. It is likely that more Mn is transported into the brain when Mn is not bound to Tf. When Tf-bound (54)Mn and (54)MnCl(2) were unilaterally injected into the lateral ventricle, radioactivity was distributed only around the ipsilateral ventricle in the Tf-bound (54)Mn group 7 days after injection, whereas it was distributed more extensively in the (54)MnCl(2) group. It is likely that Tf-bound Mn in the CSF is less readily transported into the brain parenchymal cells than the non-Tf-bound form. These results suggest that Mn is transported into the brain efficiently via a Tf-independent uptake system.

Animals↗
PubMed1978

Encephalomyelopathy following intrathecal methotrexate treatment in a child with acute leukemia.

A previously undescribed type of encephalomyelopathy after prophylactic intrathecal methotrexate (MTX) treatment for acute leukemia is reported. The patient was treated systemically with vincristine, MTX, stereoids and mercaptopurine. Radiation therapy was not given. The neurologic symptoms started 24 hours after the completion of the fifth intrathecal MTX instillation and death ensued 18 days later. The lesions consisted of superficial and sharply circumscribed areas of incomplete necrosis with astrocytosis on the base of the brain and along the insula regions, around the foramina of Luschka, and over the superior and inferior colliculi. Similar superficial lesions were found over the surface of the cerebellum and along most of the surface of the spinal cord. Most of the affected areas in the brain were located under the large subarachnoid cisterns. In the cord the lesions were most pronounced along the entrance zones of the roots. There was also a severe loss of anterior horn cells. There were no signs of meningeal leukemia, no pathological changes were caused by the intrathecal MTX treatment.

Acute Disease↗
PubMed2001

The winged helix gene, Foxb1, controls development of mammary glands and regions of the CNS that regulate the milk-ejection reflex.

The ability to lactate is a process restricted to mammals and is necessary for the survival of nonhuman mammals. Female mice carrying a null mutation in the winged helix transcription factor Foxb1 (previously Mf3/Fkh5/TWH) have lactation defects on inbred genetic backgrounds. To determine the cellular basis of the Foxb1 lactation defect we have inserted a tau-lacZ lineage marker into the locus to follow the fate of Foxb1 expressing cells. This approach has revealed that Foxb1 is expressed in epithelial cells of developing and adult mammary glands as well as previously described regions of the central nervous system. Mammary glands from C57BL/6 Foxb1-/- mice have incomplete lobuloalveolar development. In addition, the tau-lacZ lineage label was used to determine that the mammillothalamic tract was lost in all Foxb1-/- mice. Finally, morphological defects in the inferior colliculi of the midbrain in Foxb1-/- mice correlate with the inability to lactate, suggesting that the midbrain defect, but not the loss of the mammillothalamic tract, may be responsible for the lactation defect.

Animals↗
PubMed1976

Origins of axons in the cat's acoustic striae determined by injection of horseradish peroxidase into severed tracts.

Origins and terminations of fibers of the dorsal and intermediate acoustic striae were studied by surgically severing these tracts and injecting HRP into the incision. This procedure results in filling the severed axons with HRP. Filled axons were traced to cell groups of origin and to some terminations of the acoustic striae. HRP-labeled terminals were found in the cochlear nuclei as well as in periolivary cell groups. Filling of cells with HRP RANged from being complete, resulting in Golgi-like images, to being barely detectable. Labeled cells were abundant in the dorsal and posteroventral cochlear nucleus adjacent to the injection as well as scattered throughout the periolivary cell groups of both sides, being highest in concentration around the ipsilateral lateral superior olive. On the side contralateral to the injection, labeled cells were found along the medial border of the dorsal cochlear nucleus, in the interstitial nucleus of the stria of Held, and sparsely throughout the ventral cochlear nucleus. The distribution of labeled cells was similar following HRP injections of the dorsal cochlear nucleus, except that these injections revealed additional descending projections from the inferior colliculi and from the ventral nucleus of the trapezoid body of both sides. These additional projections were interpreted as entering the CN by a ventral route. Findings of this study are in accord with physiological recordings made from fibers of the acoustic striae.

Afferent Pathways↗
PubMed1979

Origin and organization of brainstem catecholamine innervation in the rat.

The catecholamine (CA) innervation of the rat brainstem was studied by biochemical analysis of discrete nuclei or areas and by glyoxylic acid-formaldehyde freeze dry fluorescence histochemistry. CA assays demonstrate that the highest norepinephrine (NE) content in brainstem is present in the trigeminal motor nucleus, nucleus tractus solitarius, dorsal motor nucleus of the vagus and nucleus raphe dorsalis. Bilateral locus coeruleus (LC) lesions do not significantly alter NE content in these nuclei but do decrease NE content in the superior and inferior colliculi, medial geniculate body, interpeduncular nucleus, pontine nuclei and the main sensory trigeminal nucleus (60-75%). Dopamine (DA) and epinephrine (E) are found in significant concentration in only a few of the nuclei examined. Fluorescence histochemical analysis indicates that two groups of NE axons innervate rat brainstem. LC neuron axons with a distinctive morphology principally innervate sensory and association nuclei of the brainstem. These disappear completely after bilateral LC lesions. The second group of axons originates from lateral and dorsal tegmental NE cell groups. Primary motor and visceral nuclei are densely innervated by fine and thick axons from these groups. Lesions of LC do not alter the NE innervation in any of the nuclei which contain axons of the second group. These results indicate that the brainstem NE innervation is divided into two major systems. The locus coeruleus complex innervates mainly primary sensory and association nuclei whereas the lateral tegmental NE neurons innervate primary motor and visceral nuclei. Although some overlap is present, the LC and lateral tegmental NE systems predominantly innervate separate and functionally distinct areas of the brainstem. DA and E neurons provide a very minor component of the brainstem CA innervation.

Animals↗
PubMed1988

Development of substance P-containing neurons in the central nervous system in mice: an immunocytochemical study.

The embryonic development of substance P (SP) in the central nervous system (CNS) of mice has been studied with the use of peroxidase antiperoxidase (PAP) immunocytochemistry. Immature SP-positive cells initially appear at embryonic day 12 (E12) in the epithalamus and in a column of cells extending from the myelencephalon throughout the length of the neural tube. By E13, SP-positive cells appear in the amygdaloid nuclear complex, the bed nucleus of the stria terminalis, and in the caudal medulla. Fibers are first detected in the stria terminalis at this age. Over the next 48 hours, a plethora of SP-positive cells appears throughout the CNS, notably in the septal area, diagonal band nucleus, piriform cortex, accumbens nucleus, hypothalamus, rostral striatum, superior and inferior colliculi, intercollicular nucleus, substantia nigra, interpeduncular nucleus, vestibular nuclei, spinal nucleus of the trigeminal, and the nucleus of the tractus solitarii. Subsequently, SP-positive neurons and fibers increase in number and staining intensity except in the medullary raphe where the apparent number of SP-positive neurons decreases after E16. Whereas the pattern of SP staining is quite similar in mice and rats, the time of initial detection of SP-like immunoreactivity in specific nuclei is 1-4 days earlier in mice than that reported in rats with different antisera.

Aging↗
PubMed1991

Distribution of cells containing mRNA encoding cholecystokinin in the rat central nervous system.

The distribution of cells containing mRNA encoding cholecystokinin was studied in the rat central nervous system by in situ hybridization histochemistry. Cholecystokinin mRNA containing neurons were considerably more numerous than the cholecystokinin-like immunoreactive neurons detected by immunocytochemistry even after colchicine pretreatment and appeared to be heavily, moderately, or lightly labeled. Such neurons were present in the olfactory bulb, olfactory nuclei, layers II-III and V-VI of the cerebral cortex, amygdaloid nuclei, subiculum, hippocampus, claustrum, endopiriform nucleus, several hypothalamic nuclei, most of the thalamic nuclei, ventral tegmental area, substantia nigra, interfascicularis nucleus, linearis rostralis, central gray, Edinger-Westphal nucleus, superior and inferior colliculi, parabrachial nucleus, reticular formation, raphe nuclei, and spinal trigeminal nucleus. This distribution partly confirmed and partly extended the previous immunohistochemical descriptions. Several brain areas such as the thalamus and the colliculi contain cholecystokinin mRNA but are devoid of perikarya exhibiting cholecystokinin-like immunoreactivity. The cerebral cortex and the hippocampus present a far higher density of cholecystokinin mRNA containing cells, including pyramidal neurons, than of perikarya containing cholecystokinin-like immunoreactivity. These results suggest that cholecystokinin or cholecystokinin-related peptides could have a functional role in numerous cerebral pathways including long projections such as cortical or thalamic projections.

Animals↗
PubMed1991

Immunohistochemical localization of calretinin in the rat hindbrain.

The localization of calretinin in the rat hindbrain was examined immunohistochemically with antiserum against calretinin purified from the guinea pig brain. Calretinin immunoreactivity was found within neuronal elements. The distribution of calretinin-immunoreactive cell bodies and fibers is presented in schematic drawings and summarized in a table. Major calretinin-immunoreactive neurons were found in the lateral and medial geniculate nuclei, substantia nigra, ventral tegmental area, interpeduncular nucleus, periaqueductal gray, mesencephalic trigeminal nucleus, superior and inferior colliculi, pontine nuclei, parabrachial nucleus, dorsal and laterodorsal tegmental nuclei, cochlear nuclei, vestibular nuclei, medullary reticular nuclei, nucleus of the solitary tract, area postrema, substantia gelatinosa of the spinal trigeminal nucleus, and cerebellum. These results show that distinct calretinin-immunoreactive neurons are widely distributed in the rat hindbrain.

Animals↗
PubMed1994

Mu, delta, and kappa opioid receptor mRNA expression in the rat CNS: an in situ hybridization study.

The mu, delta, and kappa opioid receptors are the three main types of opioid receptors found in the central nervous system (CNS) and periphery. These receptors and the peptides with which they interact are important in a number of physiological functions, including analgesia, respiration, and hormonal regulation. This study examines the expression of mu, delta, and kappa receptor mRNAs in the rat brain and spinal cord using in situ hybridization techniques. Tissue sections were hybridized with 35S-labeled cRNA probes to the rat mu (744-1,064 b), delta (304-1,287 b), and kappa (1,351-2,124 b) receptors. Each mRNA demonstrates a distinct anatomical distribution that corresponds well to known receptor binding distributions. Cells expressing mu receptor mRNA are localized in such regions as the olfactory bulb, caudate-putamen, nucleus accumbens, lateral and medial septum, diagonal band of Broca, bed nucleus of the stria terminalis, most thalamic nuclei, hippocampus, amygdala, medial preoptic area, superior and inferior colliculi, central gray, dorsal and median raphe, raphe magnus, locus coeruleus, parabrachial nucleus, pontine and medullary reticular nuclei, nucleus ambiguus, nucleus of the solitary tract, nucleus gracilis and cuneatus, dorsal motor nucleus of vagus, spinal cord, and dorsal root ganglia. Cellular localization of delta receptor mRNA varied from mu or kappa, with expression in such regions as the olfactory bulb, allo- and neocortex, caudate-putamen, nucleus accumbens, olfactory tubercle, ventromedial hypothalamus, hippocampus, amygdala, red nucleus, pontine nuclei, reticulotegmental nucleus, motor and spinal trigeminal, linear nucleus of the medulla, lateral reticular nucleus, spinal cord, and dorsal root ganglia. Cells expressing kappa receptor mRNA demonstrate a third pattern of expression, with cells localized in regions such as the claustrum, endopiriform nucleus, nucleus accumbens, olfactory tubercle, medial preoptic area, bed nucleus of the stria terminalis, amygdala, most hypothalamic nuclei, median eminence, infundibulum, substantia nigra, ventral tegmental area, raphe nuclei, paratrigeminal and spinal trigeminal, nucleus of the solitary tract, spinal cord, and dorsal root ganglia. These findings are discussed in relation to the physiological functions associated with the opioid receptors.

Animals↗
PubMed1989

Rat pup isolation distress and the brain benzodiazepine receptor.

Pharmacologic studies have demonstrated that benzodiazepines can modulate the ultrasonic vocalizations (USV) associated with social separation of rat pups. In this study, in vivo receptor autoradiography was used to determine if brain benzodiazepine receptors were functionally less available to bind an exogenous ligand during social separation. The labeled benzodiazepine receptor antagonist. 3H-RO 15-1788, was given to 10-day-old rat pups with varying schedules of social separation. In initial studies with homogenized and solubilized tissue, we found a 30% reduction in binding to cortex when pups were separated for 25 min beginning 5 min prior to tracer injection. In subsequent autoradiographic studies with this same separation schedule, the binding of 3H-RO 15-1788 was examined in 21 brain regions. Again binding was decreased in neocortex (frontal, motor, and somatosensory). In addition, we found significantly decreased binding in hippocampus, dentate gyrus, and superior and inferior colliculi. These same regions showed no alteration of in vitro binding of 3H-RO 15-1788. Therefore, these decreases in in vivo binding do not reflect changes in receptor number. The interpretation of decreased in vivo binding and implications of these results for defining the neural substrates of separation behavior are discussed.

Aging↗
PubMed1991

Widespread expression of glycine receptor subunit mRNAs in the adult and developing rat brain.

The inhibitory glycine receptor (GlyR) is a ligand-gated ion channel which mediates post-synaptic inhibition in spinal cord and other regions of the vertebrate central nervous system. Previous biochemical and molecular cloning studies have indicated heterogeneity of GlyRs during development. Here, the distribution of GlyR subunit transcripts in rat brain and spinal cord was investigated by in situ hybridization using sequence-specific oligonucleotide probes. In adult animals, GlyR alpha 1 subunit mRNA was abundant in spinal cord, but was also seen in a few brain areas, e.g. superior and inferior colliculi, whereas alpha 2 transcripts were found in several brain regions including layer VI of the cerebral cortex and hippocampus. GlyR alpha 3 subunit mRNA was expressed at low levels in cerebellum, olfactory bulb and hippocampus, while high amounts of beta subunit transcripts were widely distributed throughout spinal cord and brain. During development, alpha 2 mRNA accumulated already prenatally and decreased after birth, whereas alpha 1 and alpha 3 subunit transcripts appeared only in postnatal brain structures. Hybridization signals of beta subunit mRNA were seen already at early embryonic stages and continuously increased to high levels in adult rats. These data reveal unexpected differences in the regional and developmental expression of GlyR subunit mRNAs and point to novel functions of GlyR proteins in the mammalian central nervous system.

Animals↗
PubMed1992

Stereotaxic atlas of the brain of Octodon degus.

We present a stereotaxic atlas of the brain of the trumpet-tailed rat or degu (Octodon degus), an hystricomorph rodent native to Chile and one which has become increasingly popular as a research animal, among other things because of its use as a model for diabetic cataracts and its tendency to become hyperglycemic. The atlas contains 38 transverse and two sagittal sections of the brain covering pros-, mes-, and rhombencephalon, as well as diagrams of the brain's surface anatomy. It was constructed from brains of young adult male degus but can be used readily in studies of adult females, since there is no apparent sexual dimorphism in the brain size of this rodent. Ninety percent of 40 experimental lesions used to check the accuracy of the atlas were correctly placed. The fore- and midbrain of the degu are generally more compact than corresponding regions of the brain in the laboratory rat (suborder Myomorpha) and the guinea pig (another hystricomorph). The amygdaloid complex extends further forward in the telencephalon. Major mesencephalic nuclei and fiber tracts are more rostral in position. However, superior and inferior colliculi are much longer in degus than rats. The basic organization of the rhombencephalon is similar in degus and rats, although there are clearcut differences in the length or size of some hindbrain nuclei.

Anatomy, Artistic↗