Copper distribution in the normal human brain

Copper concentration was determined in samples from 38 areas of 7 normal human brains. The grey matter contained higher concentrations of copper than the white matter. Identical areas of the grey and white matter of the cerebral cortex showed significant differences between individuals. In the caudate nucleus the highest concentrations of copper were found in the tail followed by the body and the head, respectively. A negative linear regression between age and brain copper levels was demonstrated.

Cerebral cortex and amino acid neurotransmitters: higher levels of aspartic acid but not GABA in the frontal cortex of the rat

Endogenous levels of Aspartic acid, GABA and Glutamic acid plus Glutamine were measured in the frontal, occipital, temporal and parietal cortex. Aspartic acid levels were found higher in the frontal cortex than in the rest of the cortical areas studied. GABA, however, had a homogenous distribution among all cortical areas.

Simultaneous monitoring of 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) levels in the brains of freely moving rats by differential pulse voltammetry technique

Differential pulse voltammetry with a newly devised carbon fiber electrode was used to study the nature of striatal electrochemical signals. Voltammograms recorded from the striatum of unanesthetized rats usually yielded the combined oxidation peak (1 + 2) and peak 3. Peaks 1 and 2 could be separated by eliminating peak 1 for ascorbate by electrochemical oxidation in the brain to allow clear monitoring of peak 2 at + 120 mV for catechols and peak 3 at + 270 mV for indoles. The changes in the oxidation potentials and the amplitudes of peaks 2 and 3 corresponded to those of 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) in vivo because: the oxidation potentials of peak 2 (+ 120 mV) and peak 3 (+ 270 mV) coincided with those of DOPAC and 5-HIAA in vitro; increases in the heights of peaks 2 and 3 were observed after micro-infusion of DOPAC and 5-HIAA, respectively, into the striatum; and peak 2 height increased after injection of haloperidol and gamma-butyrolactone and decreased after amphetamine and pargyline, while peak 3 amplitude increased following injection of gamma-butyrolactone, probenecid and 5-hydroxytryptophan and decreased after pargyline. Thus, the in vivo voltammetry method enabled simultaneous and stable monitoring of the dynamic changes in DOPAC and 5-HIAA levels in the brains of freely moving rats.

Evidence for dopamine autoreceptors in mesocortical dopamine neurons

The effect of different treatments which are thought to modify dopamine (DA) synthesis by an action on DA autoreceptors was compared in the caudate nucleus and two frontal cortical areas: the medial prefrontal cortex and dorsolateral frontal cortex, having the highest and lowest DA concentration, respectively, but having equal concentrations of norepinephrine (NE); the NE to DA ratio being 3:2 and 8:1, respectively. DA synthesis was measured by the rate of DOPA accumulation after inhibition of DOPA decarboxylase. Gamma-butyrolactone (GBL) (750 mg/kg) increased DOPA accumulation by 200% in the caudate nucleus but only by 40% in the medial prefrontal cortex and was ineffective in the dorsolateral frontal cortex. Apomorphine (25-100 micrograms/kg) decreased DOPA accumulation by 7-30% in the medial prefrontal cortex and by 20-40% in the caudate nucleus in a dose-dependent manner. N-n-propylnorapomorphine (NPA) produced a similar effect within the dose range of 2.5-10 micrograms/kg. Both DA agonists were completely ineffective in the dorsolateral frontal cortical area. Haloperidol (0.5 mg/kg) increased DOPA accumulation by 80 and 220% in the medial prefrontal cortex and the caudate nucleus, respectively. It is concluded that DA autoreceptors regulate DA synthesis in the medial prefrontal cortex as in the caudate nucleus. Moreover, it was found that DOPA accumulation was approximately equal in the medial prefrontal cortex, with dense dopaminergic innervation, as in the dorsolateral area, devoid of dopaminergic terminals, suggesting that only a small fraction of cortical DA synthesis takes place in dopaminergic neurons, while the major part occurs in noradrenergic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

[Functional state of the frontal cortex and ventromedial hypothalamus during physical overexertion and experimental neurosis in the rabbit]

A change of excitability, pO2 and local cortical blood flow under a long-term maximum physical load and in conditions of experimental neurosis, was investigated in rabbits with electrodes implanted in the frontal cortex and ventromedial hypothalamus. It was found that functional activity of these structures under physical orverstrain rises as the blood flow and pO2 increase, and the excitability also increases. In experimental neurosis, a discoordination in functioning of the cortex and hypothalamus is observed. Relative stabilization of the functional state of tested structures, observed during physical overstrain, is absent in conditions of experimental neurosis.

Increased muscarinic cholinergic receptors in prefrontal cortices of medicated schizophrenics

Alterations in 3H-quinuclidinyl benzilate binding sites associated with muscarinic cholinergic receptors were investigated in orbito-frontal and medial frontal cortices from 12 schizophrenics, 6 on-drug and 6 off-drug cases, and from 10 controls. Significantly lower affinities of the sites were found in both areas of schizophrenics than controls. An increase in receptor number was shown only in the orbito-frontal cortex from schizophrenics. On-drug group of schizophrenics did, however, show a significant increase in receptor number and a significant decrease in affinity in both areas, while there were no significant differences in any binding parameters of off-drug schizophrenics from controls. Also in the caudate the similar results were obtained. It is, thus, concluded that alterations in muscarinic cholinergic receptors of schizophrenic patients result from long-term medication with antimuscarinic actions.

Antidepressant treatments: effects in rodents on dose-response curves of 5-hydroxytryptamine- and dopamine-mediated behaviours and 5-HT2 receptor number in frontal cortex

The effects of repeated electroconvulsive shock (ECS) administration, repeated desmethylimipramine injection (5 mg kg-1, twice daily for 14 days) and acute administration of the beta-adrenoceptor, clenbuterol, on 5-hydroxytryptamine (5-HT)- and dopamine-mediated behaviours in mice have been examined. All three treatments enhanced the carbidopa/5-hydroxytryptophan (5-HTP)-induced head-twitch response at all doses of 5-HTP examined, producing a parallel shift in the dose-response curve. A single ECS administration or single dose of desmethylimipramine had no effect. Only repeated ECS enhanced the locomotor response to injection of apomorphine. The dose-response curve shift was not parallel. A single ECS had no effect. A 6-hydroxydopamine lesion of brain dopamine terminals also enhanced the apomorphine response, but again did not produce a parallel shift in the dose-response curve. Both repeated ECS and repeated desmethylimipramine administration to rats increased the number of 5-HT2 receptor sites in rat brain. Clenbuterol had no effect. The enhancing effects of repeated ECS and clenbuterol administration on the 5-HTP-induced head-twitch response were additive. Enhanced 5-HT-mediated behavioural responses are seen in both mice and rats after these treatments. If it is assumed, therefore, that similar receptor changes occur in both species it appears that there is no relationship in either behavioural system between the ability of the treatment to alter receptor number and the change in the dose-response curve (parallel or non-parallel). All three antidepressant treatments (ECS, a tricyclic and a beta-adrenoceptor agonist) increase 5-HT-mediated behavioural responses although clenbuterol did not increase 5-HT2 receptor number. Only ECS increased dopamine-mediated responses.

Putative amino acid neurotransmitters and the nucleus dorsomedialis thalamus-prefrontal cortex pathway in the rat

Endogenous levels of putative amino acid neurotransmitters (glycine, glutamic acid, aspartic acid, and GABA) in medial and sulcal prefrontal cortex of the rat were analyzed using gas liquid chromatography. No changes were found in the levels of these amino acids in medial and sulcal prefrontal cortex after lesion of the nucleus dorsomedialis of the thalamus suggesting, therefore, that the NDMT-prefrontal cortex pathway is not mediated by these amino acids.

SL76002 - effect on gamma-aminobutyric acid and dopamine in animals treated chronically with haloperidol

Daily haloperidol injection at the dose of 5 mg/kg for 34 days did not change the levels of dopamine in the corpus striatum, frontal cortex, and midbrain of rats. However, the gamma-aminobutyric acid (GABA) level was increased by 27% in the corpus striatum. Haloperidol withdrawal for 4 days after 30-day treatment increased GABA levels of the corpus striatum and the frontal cortex to 140 and 125%, respectively, of control values. GABA, by its inhibitory actions, depleted dopamine level in the corpus striatum and frontal cortex by 17 and 29%, respectively. Administration of SL76002, a new GABA agonist, for 4 days at the dose of 400 mg/kg i.p. to haloperidol-withdrawn rats increased GABA levels in striatum by 23% of control values. The dopamine levels were also decreased significantly in the frontal cortex and corpus striatum. Our data demonstrate that SL76002, by altering the GABA levels, probably influences DA functioning in the corpus striatum, a region responsible for involuntary movements.

Developmental changes of glial fibrillary acidic protein in cerebral white matter

Developmental changes were observed in the glial fibrillary acidic protein (GFAP)--positive glia of cerebral white matter (including myelination glia) in the frontal lobes of 38 normal cases. With age, GFAP-positive processes gradually became larger and their location shifted from preponderantly in the deep white matter to mostly in the superficial white matter. This shift in pattern of GFAP-positive glia may be related to the parallel changes in perinatal brains in the localization of leukomalacic lesions. However, the shift is a normal developmental phenomenon on which such lesions are superimposed.

Sclerosing leucoencephalopathy with membranocystic lesions of adipose tissue: a contribution to the pathology of Nasu disease

A case of sclerosing leucoencephalopathy with membranocystic lesions of adipose tissue was reported. A 38-year-old Japanese housewife, whose parents were consanguineous, developed gradually neuropsychiatric symptoms characterized by euphoria, gait disturbance and urinary incontinence, followed by spastic tetraplegia with epileptic convulsions and died eight years later. Neuropathologically a form of sudanophilic leucodystrophy with a prominent fibrillary gliosis (dissociation glio-myelinique) associated with axonal spheroids and calcospherite depositions was revealed. A peculiar membranocystic lesion of adipose tissue was recognized not only in the bone marrow but also in other areas. However, no apparent bone pathology was observed except for a ring-like pleated lamellar structure. This case was thought to be classified as heterogeneous phenotype of membranous lipodystrophy (Nasu).

Central serotonergic receptors: evidence for heterogeneity and characterization by ligand-binding

Evidence has accumulated which suggests that receptors for serotonin exist in multiple forms both in the central nervous system and the periphery. This has come from the use of a variety of techniques and a number of different tissues. In the central nervous system the ligand-binding technique has proven particularly useful for characterizing different types of serotonin receptors, and two major classes of central serotonin receptors have been proposed on the basis of studies using this procedure. The first group (5-HT1 receptors) is defined by the high-affinity binding of 3H-serotonin in the brain, and the second (5-HT2 receptors) is defined by the high-affinity binding of 3H-spiperone in the frontal cortex. The 5-HT1 sites have themselves been shown to be a heterogeneous group, and recent studies suggest that it is possible to synthesize tryptamine analogues which can discriminate between the different types of 5-HT1 receptors. Such studies suggest the possibility of designing new selective serotonin agonists and antagonists for the study of the effects of specific receptor subtypes on behavioral and physiological activities.

Increased 3H-spiperone binding sites in mesolimbic area related to methamphetamine-induced behavioral hypersensitivity

The specific 3H-spiperone binding to membrane homogenates of the striatum, mesolimbic area, and frontal cortex was examined in two groups of rats pretreated once daily with saline or 4 mg/kg of methamphetamine (MAP) for 14 days. At 7 days following cessation of chronic pretreatment, all rats received an injection of 4 mg/kg of MAP and were decapitated 1 hr after the injection. In the chronic saline-pretreatment group, the single administration of MAP induced significant changes in the number (Bmax) of specific 3H-spiperone binding sites (a decrease in the striatum and an increase in the mesolimbic area and frontal cortex), but no significant changes in the affinity (KD) in any brain area. The chronic MAP pretreatment markedly augmented the changes in Bmax in the striatum and mesolimbic area. The increase in specific 3H-spiperone binding sites in the mesolimbic area is discussed in relation to MAP-induced behavioral hypersensitivity.

Neurochemical investigations of aged human brain cortex

Neurochemical investigation of FC and TC of 10 brains of old age and 10 controls did not reveal significant differences of total ganglioside, DNA, protein, and lipid levels. With regard to individual gangliosides there was a significant decrease of the percentage of GM1 in the FC and a significant decrease of GM1, GD1a, GM2 as well as a significant increase of GD1b and GD3 in the TC of the aged brains. Our results present some neurochemical evidence for regionally different changes in neuronal processes in the aged human brain, whereas neuronal cell loss might play only a minor role in this condition.

Decreased receptor-binding sites for kainic acid in brains of patients with Huntington's disease

The specific binding of (3H)kainic acid (KA) to high- and low-affinity receptor sites was assayed in postmortem samples from the brains of patients affected with Huntington's disease (HD) and age-matched controls. Treatment of rat brain with conditions that closely mimic the temperature gradient occurring in postmortem human brain only slightly but not significantly decreased receptor binding by 12 hr after death. In HD brains, total specific binding of (3H)KA was reduced in the caudate nucleus by 51%, putamen by 77%, and frontal cortex by 47%. Specific binding to the high-affinity site was virtually undetectable in the caudate nucleus and was reduced by 90% in the putamen from HD brains. No significant alterations in specific binding of (3H)KA were noted in the insular or temporal cortex, hippocampus, or cerebellum. Thus, losses of KA receptor binding were mainly localized to those regions of the HD brain that are most severely affected by neuronal degeneration, and the high-affinity receptor site appeared more affected.

Serotonin receptors in hippocampus and frontal cortex

The inhibition by various serotonin agonists and antagonists of the binding of 3 nM 3H-d-LSD, 1.7 nM 3H-serotonin and 0.22 nM 3H-spiperone to homogenates of calf hippocampus and frontal cortex was studied. The 50% inhibitory concentration (IC50) for these drugs versus 3H-d-LSD binding had similar values to and correlated with corresponding IC50 values versus 3H-serotonin binding in the hippocampus, suggesting that 3H-LSD and 3H-serotonin label similar sites in this region. In the calf frontal cortex, serotonin revealed a biphasic inhibition against 3H-d-LSD binding and the tryptamines inhibited over a concentration range of 10 000-fold. The IC25 values of various drugs versus 3H-d-LSD binding correlated with the IC50 values versus 3H-serotonin, but did not correlate with the IC50 values versus 3H-spiperone. These data suggest that 3H-d-LSD bound to more than one serotonin site in the calf frontal cortex and that 3H-spiperone bound to a separate serotonergic site. Scatchard analyses of the binding for these three 3H-ligands indicated that in the calf frontal cortex the density of 3H-d-LSD sites was approximately equal to the sum of the densities for 3H-serotonin (S-1 sites) and 3H-spiperone (S-2 sites). Two weeks after serotonin-depleting radiofrequency heat lesions of the midbrain dorsal and median raphe nuclei in rats, both 3H-serotonin and 3H-LSD showed enhanced binding in the hippocampus. These data support previous suggestions that supersensitivity develops specifically in serotonin receptors following afferent denervation.

[Plasma protein and cerebral soluble protein disc electrophoresis in Down's syndrome]

Blood plasma proteins and soluble proteins from brain lobus frontalis of patients with mongolism were studied using polyacrylamide gel disc electrophoresis. A decrease in content of albumins, proteins of Gc system, transferrine, fast posttransferrines and an increase in amount of immunoglobulin proteins as well as of alpha 2-macroglobulin were observed in the preparations of blood plasma proteins. These alterations were apparently determined by impairments in functions of protein-synthesizing systems. Content of four different protein fractions was altered as shown by brain proteinogramms.

Brain and CSF proteins in Creutzfeldt-Jakob disease

Cerebrospinal fluid was analyzed from 8 patients with Creutzfeldt-Jakob disease. No special abnormalities were found concerning cells, total protein content or the concentrations of albumin and IgG. Routine agar gel electrophoresis was normal. Grey and white cerebral matter were analyzed from 1 patient. The total protein content was reduced in grey matter and on isoelectric focusing a distinct band at pH 8.8 was absent.

Regional concentrations of serotonin, tryptophan, 5-hydroxyindoleacetic acid, dopamine, and norepinephrine in the ovine brain

Regional concentrations of tryptophan, serotonin (5HT), 5-hydroxyindoleacetic acid (5HIAA), norepinephrine, and dopamine were determined in the ovine brain. Tryptophan concentrations varied between 18.6 nmoles/g of tissue (hypothalamus, midbrain) and 26.9 nmoles/g (cerebellum). The 5HT concentrations varied 0.34 nmoles/g (cerebellum) and 3.75 nmoles/g (midbrain). The concentration of 5HIAA varied between 1.78 nmoles/g (cerebellum) and 5.02 nmoles/g (hypothalamus). Large concentrations of norepinephrine were found in the hypothalamus (4.37 nmoles/g) and midbrain (2.08 nmoles/g), while the frontal cortex, thalamaus, hippocampus, and cerebellum were all relatively low in norepinephrine (0.65 to 0.95 nmoles/g). The concentration of dopamine was between 0.32 nmoles/g (hippocampus) and 39.8 nmoles/g (caudate nucleus). Generally, the distribution of these compounds in the ovine brain is similar to their regional distribution in other mammalian species. It was observed, however, that the ratio of 5HT/5HIAA appears to be relatively lower in sheep than in other species, suggesting that interspecies differences in the metabolism of 5HT or elimination of 5HIAA (or both) may exist.

Endogenous levels of tryptophan, serotonin and 5-hydroxyindole acetic acid in the developing brain of the cat

Using spectrofluorimetric methods, endogenous levels of tryptophan (TRP), serotonin (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) were determined in various structures of the growing brain of cats. After one month, 5-HT metabolism is comparable to that observed in adult cats. The third week after birth is marked by increasing levels of TRP and 5-HIAA and seems to be a critical period for the maturation of serotoninergic neurons.

Subcellular distribution of corticotropin-releasing factor in the medio-basal hypothalamus of the rat

Subcellular fractionation of the mediobasal hypothalamus (MBH) and frontal cerebral cortex was performed by differential and discontinuous sucrose gradient centrifugation. Corticotropin-releasing factor (CRF) activity of the different fractions was evaluated by bioassay. Significant CRF activity was found in acidic extracts of the MBH but not of the cerebral cortex. About 80% of the MBH effect on adrenocorticotropic hormone release was recovered in the crude mitochondrial pellet (P2) which contains synaptosomes. After further fractionation, distribution of CRF activity paralleled that of lactate dehydrogenase activity, a marker of the soluble cytoplasm. It is concluded that most CRF in the MBH is located in nerve endings as already shown for several other neurohormones.