The laminar histamine receptor system in human prefrontal cortex suggests multiple levels of histaminergic regulation

Human prefrontal cortex is essential for high brain functions and its activity is modulated by multiple neurotransmitters, including histamine. However, the histamine receptors in this brain area have not been systematically studied so far. In situ hybridization and receptor binding autoradiography were employed to map and quantify the mRNA expression and receptor binding of three of the four histamine receptors (H(1), H(2), H(3)). mRNA expression and receptor binding of these three histamine receptors displayed characteristic laminar distribution patterns. Both H(1) and H(3) receptor mRNAs were mainly expressed in the deeper layers (H(1) in laminae V and VI; H(3) in lamina V), where most of the corticothalamic projections originate, whereas H(2) receptor mRNA was primarily expressed in the superficial layer II. Receptor ligand binding of these three histamine receptors displayed relatively even distribution patterns throughout the gray matter. However, higher densities of H(1) and H(3) receptor radioligand binding sites were seen in the middle layers III and IV that receive abundant thalamic inputs and where some of the apical dendrites of the deep-layer pyramidal neurons terminate, whereas higher density of H(2) receptor radioligand binding sites was seen in the superficial layers I-III. The results, together with data on histaminergic regulation of thalamic oscillations suggest that histamine regulates both cortico-cortical and thalamo-cortical circuits. As histamine receptors are also abundant in thalamus, histamine may be involved also in human diseases of the thalamocortical system.     

Glutamate recognition sites in human fetal brain

We used in vitro autoradiography with [3H]glutamate to examine the distribution of glutamate recognition sites in 18 and 21 week gestation human fetal brains. We found a wide distribution of [3H]glutamate binding in both specimens, in a pattern distinct from that reported in adult brain using the same autoradiographic methods. In fetal brain, prominent [3H]glutamate binding was evident in hippocampal formation, caudate-putamen, globus pallidus, subthalamic nucleus, reticular nucleus of thalamus and substantia innominata.     

Localization of cannabinoid receptor in the human developing and adult basal ganglia. Higher levels in the striatonigral neurons.

In the infant and adult human basal ganglia, the finding of mRNA exclusively in the striatal medium-sized neurons together with the detection of [3H]CP55,940 binding sites in the caudate-putamen, accumbens, substantia nigra pars reticulata and globus pallidus suggests cannabinoid receptor localization on the striatal intrinsic enkephalinergic and substance P-projecting neurons and on their nigral and pallidal terminals. However, the consistent finding of higher binding in the substantia nigra pars reticulata and medial part of the globus pallidus over its lateral segment suggests cannabinoid receptor enrichment on the striatal substance P neurons which express selectively the dopamine D1 receptor.     

Distribution and binding parameters of GABAA receptors in the thalamic nuclei of Macaca mulatta and changes caused by lesioning in the globus pallidus and reticular thalamic nucleus

Ascending output from the basal ganglia to the primate motor thalamus is carried by GABAergic nigro- and pallido-thalamic pathways, which interact with intrinsic thalamic GABAergic systems represented in primates by local circuit neurons and axons of the reticular thalamic nucleus. Disease-triggered pathological processes in the basal ganglia can compromise any of these pathways either directly or indirectly, yet the effects of basal ganglia lesioning on its thalamic afferent-receiving territories has not been studied in primates. Two GABA(A) receptor ligands, [(3)H]muscimol and [(3)H]flunitrazepam, were used to study the distribution and binding properties of the receptor in intact monkeys, those with kainic acid lesions in the globus pallidus, and those with ibotenic acid lesions in the reticular nucleus using quantitative autoradiographic technique on cryostat sections of fresh frozen brain tissue. In control monkeys the binding affinities for [(3)H]muscimol averaged 50 nM in the thalamic nuclei and 86 nM in the basal ganglia while the binding densities varied (maximum density of binding sites [Bmax] range of 99.4-1000.1 fmol/mg of tissue). Binding affinities and Bmax values for [(3)H]flunitrazepam averaged 2.02 nM and 81-113 fmol/mg of tissue, respectively. Addition of 100-microM GABA increased average affinity to 1.35 nM whereas Bmax values increased anywhere from 1-50% in different nuclei. Zolpidem (100 nM) decreased binding by 68-80%. Bmax values for both ligands were decreased at the two survival times in both medial and lateral globus pallidus implying involvement of both nuclei in the lesion. Statistically significant, 40% decrease (P=0.055) of Bmax for [(3)H]muscimol was observed in the ventral anterior nucleus pars densicellularis (VAdc, the main pallidal projection territory in the thalamus) 1 week after globus pallidus lesioning and a 36% decrease (P=0.017) 4 months post-lesioning. In contrast, [(3)H]flunitrazepam Bmax values in the VAdc of the same animals were increased by 23% (P=0.021) at 1 week and 28% (P=0.005) 4 months postlesion, respectively. One week after the reticular nucleus lesioning, the binding densities of [(3)H]muscimol and [(3)H]flunitrazepam were decreased in the thalamic nuclei receiving projections from the lesioned reticular nucleus sector by approximately 50% (P<0.05) and 10-33% (P<0.05), respectively. The results suggest that different GABA(A) receptor subtypes are associated with different GABAergic systems in the thalamus which react differently to deafferentation.     

The regional distribution of sulphonylurea binding sites in rat brain

Sulphonylureas such as glibenclamide, which are used in the treatment of Type-2 diabetes, are inhibitors of ATP-sensitive potassium channels. These channels link cellular metabolism to membrane electrical activity and it is likely that they are closely associated with glibenclamide binding sites. Quantitative autoradiography was used to localize high-affinity [3H]glibenclamide binding sites in coronal sections of rat brain. The relative density of binding sites was found to correlate well with the relative capacity of sites determined in homogenate assays. There was no evidence of any variation of affinity between brain regions. The highest levels of binding were found in the substantia nigra with high levels in the globus pallidus, cerebral cortex, hippocampus and caudate-putamen, intermediate levels in the cerebellum, and low levels in the hypothalamus and pons. The density of [3H]glibenclamide binding sites was low in glucose-responsive brain regions, known to contain ATP-sensitive potassium channels that are inhibited by sulphonylureas. However, higher densities were associated with brain regions (often limbic structures) active during temporal lobe epilepsy. In at least two of these structures, the CA3 region of the hippocampus and the substantia nigra, it is probable that these sites are coupled to ATP-sensitive potassium channels. These results are discussed with reference to the reported actions of ATP-sensitive potassium channels on CNS function.     

Dopamine receptors in human brain: autoradiographic distribution of D2 sites

We have studied the detailed anatomical distribution of D2 receptors in human post mortem brain tissue using quantitative autoradiographic techniques. D2 receptors were labeled using the specific D2 agonist [3H]CV 205-502 and the antagonist [3H]spiroperidol. The pattern of D2 receptor distribution observed with the two ligands was very similar. The highest densities were found in the nucleus caudatus, putamen, nucleus accumbens and olfactory tubercle followed by the substantia nigra, where D2 receptors were mainly concentrated in the pars compacta. Lower but still significant densities were associated with the lateral part of the globus pallidus and CA1 and CA3 fields of the hippocampus. The medial part of the globus pallidus, the dentate gyrus and the amygdala showed low to very low densities of D2 receptors. Almost negligible amounts of binding were observed in the olfactory bulb, diencephalon, brainstem, cerebellum and most parts of the neocortex. Our results are comparable with previously reported localizations of D2 receptors in the human and rat brain. We also report the lack of the so-called spirodecanone binding sites in the human brain. The localization of D2 receptors is compared with the distribution of D1 receptors.     

Autoradiographic distribution of the D1 agonist [3H]SKF 38393, in the rat brain and spinal cord. Comparison with the distribution of D2 dopamine receptors

The regional distribution of the specific D1 agonist [3H]SKF 38393 (SKF 38393, 2,3,4,5-tetra-hydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine) has been studied autoradiographically in the rat CNS. The binding of [3H]SKF 38393 to striatal sections was saturable, stereospecific, reversible, of high affinity (Kd = 9.9 nM) and partly sodium sensitive; it occurred at a single population of sites and possessed the pharmacological characteristics of the dopamine D1 receptor. The highest levels of [3H]SKF 38393 binding sites were found in the caudate-putamen, nucleus accumbens, olfactory tubercle and substantia nigra. Moderately high concentrations of the [3H]ligand were observed in the amygdala, endopyriform nucleus, nucleus olfactorius anterior, lateral septum, primary olfactory cortex, cerebellum (molecular layer) and spinal cord. An intermediate labelling was found in the thalamus, habenula, subthalamic nucleus, hypothalamus, ventral tegmental area, superior colliculus, hippocampus and cerebral cortex. Moderate levels of [3H]SKF 38393 binding were observed in the globus pallidus and arcuate nucleus. The autoradiographic distribution of [3H]SKF 38393 overlapped with that of [3H]N,n-propylnorapomorphine, a radioligand which labels the D2 dopamine receptors, in a number of dopamine-rich brain areas but there were several areas which exhibited a high density of [3H]SKF 38393 binding sites but undetectable concentrations of [3H]N,n-propylnorapomorphine. Moreover, in the spinal cord, the subregional localization of these [3H]ligands clearly differed. Intrastriatal injection of ibotenic acid caused a large decrease in [3H]SKF 38393 and [3H]N,n-propylnorapomorphine binding in the striatum and provoked a reduction of [3H]SKF 38393 but not [3H]N,n-propylnorapomorphine binding in the substantia nigra confirming the view that nigral D1 but not D2 receptors are located on striatonigral fibres.     

Chronic use of marijuana decreases cannabinoid receptor binding and mRNA expression in the human brain

Chronic exposure to Cannabis sativa (marijuana) produced a significant down-regulation of cannabinoid receptor in the postmortem human brain. The significant decrease in maximal binding capacity was not accompanied by changes in the affinity constant. [3H]SR141716A binding was reduced in the caudate nucleus, putamen and in the accumbens nucleus. A significant decrease of binding sites was seen in the globus pallidus. Also in the ventral tegmental area and substantia nigra pars reticulata quantitative analysis of the density of receptors shows a significant reduction in [3H]SR141716A binding. In Cannabis sativa user brains, compared with normal brains [3H]SR141716A binding was reduced only in the hippocampus. The density of cannabinoid receptor 1 mRNA-positive neurons was significantly lower in Cannabis sativa users than in control brains for the caudate nucleus, putamen, accumbens nucleus and hippocampal region (CA1-CA4, areas of Ammon's horn). No hybridization was seen in the mesencephalon and globus pallidus.     

Anatomical correlates of morphine-withdrawal syndrome: Differential participation of structures located within the limbic system and striatum

Morphine-withdrawal signs have been induced, in morphine-dependent rats, by microinjection of naloxone in various diencephalic and telencephalic structures. A differential participation of the central amygdala, lateral septum, dorsal hippocampus, medial thalamic nuclei, globus pallidus and caudate-putamen has been observed for the following signs: jumping, wet-dog shakes, paw tremor, chewing and diarrhea. Amygdala, medial thalamus and globus pallidus were the most sensitive to local injection of naloxone.     

Dopamine receptors in human brain: autoradiographic distribution of D1 sites

The distribution of dopamine D1 receptors has been determined in post mortem human brain tissues using in vitro receptor autoradiography, with ([3H]N-methyl) SCH 23390 as ligand. The highest densities of dopamine D1 sites were seen in the nucleus caudatus, putamen, globus pallidus pars medialis and substantia nigra. Intermediate densities were associated with the amygdala, mammillary bodies, cerebral cortex and CA1. The remaining part of the hippocampus as well as the diencephalon, brainstem and cerebellum contained low levels of [3H]SCH 23390 binding sites. The distribution of D1 receptors in the human brain closely resembles that reported for the rat brain. In addition, there was a good correlation between the anatomical localization of D1 sites and the distribution of dopaminergic nerve terminals in the central nervous system. The densities of D1 receptors in the human brain were observed to markedly decrease with age during the first decades of life. However, no further modifications were found beyond the age of 40 years. We did not observe any significant influence of other parameters such as gender and post mortem delay in our samples.     

Autoradiographic localization of D1 and D2 dopamine receptors in the human brain

The distribution of dopamine D1 and D2 receptors in several human brain regions was investigated using autoradiography with the radioligands [3H]SCH 23390 and [3H]spiroperidol. The highest densities of both dopamine receptor types are seen in the nucleus caudatus, putamen and nucleus accumbens. Whereas the density of the D2 receptors is similar in the two segments of the globus pallidus, the pars medialis of the globus pallidus contains a three-fold higher concentration of D1 receptors than the pars lateralis. D1 and D2 receptors are present in the amygdala and substantia nigra. Both receptor types are absent in the cerebellum. The thalamus contains low densities of D1 receptors but no D2 receptors. Only D2 receptors are seen in the anterior lobe of the pituitary gland. The whole cerebral cortex is rich in D1 receptors, while D2 receptors, in low concentrations, are confined to the entorhinal area and cingulate cortex.     

基于磁共振T1成像的帕金森病相关脑结构体积差异性分析

目的 应用3.0T磁共振T1成像分析帕金森病（PD）患者脑结构如尾状核、壳核、苍白球、中脑、背侧丘脑、海马、杏仁核体积的变化,探讨MRI体积测量在PD引起形态学改变的应用及在早期诊断上的意义。 方法 采用3.0T MRI对40例早中期PD患者和年龄匹配的32名正常人进行扫描,分别测量出全脑体积、双侧尾状核、双侧壳核、双侧苍白球、中脑、双侧背侧丘脑、双侧海马、双侧杏仁核的体积,对体积值标准化处理后,使用SPSS 22.0软件对数据进行统计学分析。 结果 比较早中期PD患者和正常对照组发现, PD患者的全脑、双侧尾状核、双侧海马、双侧杏仁核的标准化体积和正常人比较差异无显著性（P>0.05）;双侧壳核、双侧苍白球、双侧背侧丘脑、中脑标准化体积差异有显著性（P<0.05）。 结论 基于MRI测量尾状核、壳核、苍白球、中脑、背侧丘脑、海马与杏仁核的体积的变化能为PD的辅助诊断提供一定帮助。     

Distribution of gephyrin in the human brain: an immunohistochemical analysis

Gephyrin is an ubiquitously expressed protein that, in the central nervous system, generates a protein scaffold to anchor inhibitory neurotransmitter receptors in the postsynaptic membrane. It was first identified as a protein component of the glycine receptor complex. Recent studies have demonstrated that gephyrin is colocalized with several subtypes of GABA(A) receptors and is part of postsynaptic GABA(A) receptor clusters. Here, we describe a study of the regional and cellular distribution of gephyrin in the human brain, determined by immunohistochemical localisation at the light and confocal laser scanning microscopic levels. At the regional level, gephyrin immunoreactivity was observed in most of the major brain regions examined. The most intense staining was in the cerebral cortex, hippocampus and caudate-putamen, in various brainstem nuclei with more moderate levels in the thalamus and cerebellum. At the cellular level gephyrin immunoreactivity was present on the plasma membranes of the soma and dendrites of pyramidal neurons throughout the various cortical regions examined. In the hippocampus, intense staining was observed on the granule cells of the dentate gyrus, and neurons of the CA1 and CA3 regions showed intense punctate gephyrin staining on their apical dendrites and cell bodies. Gephyrin immunoreactivity was also observed on neurons in the thalamus, globus pallidus and substantia nigra. In the putamen intense labelling of the striosomes was observed; most of the medium-sized neurons in the caudate-putamen were weakly labelled and many large neurons of the striatum were conspicuously stained. Many of the brainstem nuclei, notably the dorsal motor nucleus of the vagus, hypoglossal nucleus, trigeminal nucleus and inferior olive were all labelled with gephyrin. The spinal cord also showed high levels of gephyrin immunoreactivity. Our results demonstrate that the anchoring protein gephyrin is ubiquitously present in the human brain. We therefore suggest that gephyrin may have a central organizer role in assembling and stabilizing inhibitory postsynaptic membranes in human brain and is similar in function to those observed in the rodent brain. These findings contribute towards elucidating the role of gephyrin in the human brain.     

Autoradiographic localization of delta opiate receptors in rat and human brain

In vitro quantitative receptor autoradiography was performed on frozen sections of rat and human brain to visualize delta opiate receptors using the specific ligand [3H][D-Pen2, D-Pen5]enkephalin. For comparison, rat brain sections were also labelled with [3H]D-Ala2, D-Leu5-enkephalin. Compounds which block mu and kappa binding were included to make the [3H]D-Ala2, D-Leu5-enkephalin binding more specific. The two ligands had similar, but not identical, distributions in rat forebrain sections. Sites labelled with [3H][D-Pen2,D-Pen5]enkephalin were distributed heterogeneously within the layers of the frontal and parietal cerebral cortex, with high densities in the superficial and deep cortical layers. The claustrum and striatum had the most delta sites, whereas the globus pallidus had no delta binding. The distribution of [3H]D-Ala2,D-Leu5-enkephalin binding sites was similar to that of [3H][D-Pen2,D-Pen5]enkephalin, except that there was less heterogeneity in the frontal cortex. In the human brain regions studied, the highest delta binding was in caudate, putamen, temporal cortex and amygdala. There was less heterogeneity in the binding of [D-Pen2,D-Pen5]enkephalin in the human cortex than in the rat. No delta binding was seen in the medial and lateral segments of the globus pallidus. In both species, a discrepancy between the high enkephalin content of the globus pallidus and the absence of delta binding was apparent.     

Quantitative light microscopic autoradiographic localization of cholinergic muscarinic receptors in the human brain: forebrain

The distribution of muscarinic cholinergic receptors in the human forebrain and cerebellum was studied in detail by quantitative autoradiography using N-[3H]methylscopolamine as a ligand. Only postmortem tissue from patients free of neurological diseases was used in this study. The highest densities of muscarinic cholinergic receptors were found in the striatum, olfactory tubercle and tuberal nuclei of the hypothalamus. Intermediate to high densities were observed in the amygdala, hippocampal formation and cerebral cortex. In the thalamus muscarinic cholinergic receptors were heterogeneously distributed, with densities ranging from very low to intermediate or high. N-[3H]Methylscopolamine binding was low in the hypothalamus, globus pallidus and basal forebrain nuclei, and very low in the cerebellum and white matter tracts. The localization of the putative muscarinic cholinergic receptors subtypes M1 and M2 was analysed in parallel using carbachol and pirenzepine at a single concentration to partially inhibit N-[3H]methylscopolamine binding. Mixed populations of both subtypes were found in all regions. M1 sites were largely predominant in the basal ganglia, amygdala and hippocampus, and constituted the majority of muscarinic cholinergic receptors in the cerebral cortex. M2 sites were preferentially localized in the diencephalon, basal forebrain and cerebellum. In some areas such as the striatum and substantia innominata there was a tendency to lower densities of muscarinic cholinergic receptors with increasing age. In general, we observed a slight decrease in M2 sites in elderly cases. Muscarinic cholinergic receptor concentrations seemed to be reduced following longer postmortem periods. The distribution of acetylcholinesterase was also studied using histochemical methods, and compared with the localization of muscarinic cholinergic receptors and other cholinergic markers. The correlation between the presence of muscarinic cholinergic receptors and the involvement of cholinergic mechanisms in the function of specific brain areas is discussed. Their implication in neurological diseases is also reviewed.     

Age-related changes in histamine receptor mRNA levels in the mouse brain

Several lines of evidence indicate that the histaminergic (HA) system is important for wakefulness and behavioral state regulation. We investigated the hypothesis that age-related changes in HA system occur which may be related to decreased alertness in aging. Although histidine decarboxylase mRNA levels did not change with age in C57BL/6 mice, significant differences were found in histamine H1 receptor (H1R), histamine H2 receptor (H2R), and histamine H3 receptor (H3R) mRNA levels in several brain regions. The most widespread changes were observed in H1R mRNA, which were significantly lower (27-38%) in the cortex, hypothalamus, hippocampus and medulla of 24-month-old mice relative to 3-month-old animals. Age-related changes in H2R mRNA levels were restricted to the pons and cerebellum and decreased H3R mRNA was found only in the medulla. In conjunction with the age-related decrease in hypocretin receptor 2 mRNA levels we have previously reported, decreased HA receptor mRNA levels may contribute to diminished alertness, sleep continuity, and diurnal rhythms of sleep and wakefulness in the aged.     

Comparison of neuronal inositol 1,4,5-trisphosphate 3-kinase and receptor mRNA distributions in the adult rat brain using in situ hybridization histochemistry.

As a result of its interaction with a specific receptor, inositol 1,4,5-trisphosphate mobilizes intracellular calcium. The metabolism of inositol 1,4,5-trisphosphate is rather complex: inositol 1,4,5-trisphosphate 3-kinase produces inositol 1,3,4,5-tetrakisphosphate, a putative second messenger. In order to elucidate inositol 1,3,4,5-tetrakisphosphate function, a comparative in situ hybridization study of the distributions of inositol 1,4,5-trisphosphate 3-kinase and receptor mRNAs was performed in the adult rat brain using oligonucleotides derived from their cDNA sequences. The neuronal distributions of the mRNA for the receptor were larger than for the kinase. Highest levels of both mRNAs were found in the cerebellar Purkinje cells, where they were enriched in their neuronal perikarya and to a lesser extent in their dendrites. In addition to the cerebellum, mRNAs were mainly detected in the hippocampal pyramidal cells of the CA1 sector of the Ammon's horn and in the granule cells of the dentate gyrus, and also in a majority of the neurons in the cortical layers II-III and V, especially in the frontal cortex and cingulate cortex; caudate-putamen, accumbens, olfactory tubercle and Calleja islets; claustrum; anterior olfactory nucleus; taenia tecta; piriform cortex; dorsolateral septum; bed nucleus stria terminalis; amygdala; hippocampal CA2-4 sectors and subiculum. The inositol 1,4,5-trisphosphate receptor mRNA but not kinase mRNA was found in a majority of the neurons in the thalamus, especially in the parafascicular nucleus; hypothalamus, especially the medial hypothalamus; substantia nigra pars compacta and ventral tegmental area; superior colliculus; lateral interpeduncular nucleus and central gray. Taking into account the limitation in sensitivity of the technique, both mRNAs were not detected in glial cells and in the olfactory bulb; basal nucleus of Meynert, diagonal band nuclei; medial septal nucleus; substantia innominata; globus pallidus; entopeduncular nucleus; substantia nigra pars reticulata; ventral pallidum; subthalamic nucleus; spinal cord and dorsal root ganglia. In conclusion, cerebellum and hippocampus appear to contain almost similar levels of kinase mRNA. This is in contrast to receptor mRNA levels which were at much higher levels in the cerebellum when compared with the hippocampus. For this reason, we have chosen hippocampal CA1 pyramidal cells and dentate gyrus granule cells for studying inositol 1,4,5-trisphosphate 3-kinase function.     

Localization of DJ-1 mRNA in the mouse brain

DJ-1 is mutated in autosomal recessive, early onset Parkinson's disease but the exact localization of the DJ-1 gene product in the mammalian brain is largely unknown. We aimed to evaluate the DJ-1 mRNA expression pattern in the mouse brain. Serial coronal sections of brains of five male and five female adult mice were investigated by using in situ hybridization with a DJ-1 specific 35S-labeled oligonucleotide probe. Hybridized sections were analyzed after exposure to autoradiography films and after coating with a photographic emulsion. DJ-1 was heterogeneously expressed throughout the mouse central nervous system. A high expression of DJ-1 mRNA was detected in neuronal and non-neuronal populations of several structures of the motor system such as the substantia nigra, the red nucleus, the caudate putamen, the globus pallidus, and the deep nuclei of the cerebellum. Furthermore, DJ-1 mRNA was also highly expressed in non-motor structures including the hippocampus, the olfactory bulb, the reticular nucleus of the thalamus, and the piriform cortex. The high expression of DJ-1 mRNA in brain regions involved in motor control is compatible with the occurrence of parkinsonian symptoms after DJ-1 mutations. However, expression in other regions indicates that a dysfunction of DJ-1 may contribute to additional clinical features in patients with a DJ-1 mutation.