Filaments and rod-shaped tubulated bodies in the endothelia of anterior cerebral arteries in young rats

Summary Endothelia of the anterior cerebral arteries in rats aged 1 to 3 days were studied. Thin (about 50–90 Å) and thick (about 100–110 Å) filaments are present in the endothelia. Numerous spherical- or rod-shaped bodies, measuring approximately 0.07 to 0.3 m in diameter and up to 0.6 m in length occur in the endothelial cells. These bodies contain a tubular structure. The diameter of the individual tubules is about 200 Å. The present observations suggest that spherical- or rod-shaped inclusions are first synthesized in the rough endoplasmic reticulum and thereafter these materials are transported into the Golgi complex for maturation. A small number of the inclusions, however, may originate directly from the rough endoplasmic reticulum and not pass through the Golgi apparatus.A part of this study was demonstrated at the 70th Versammlung der Anatomischen Gesellschaft in Düsseldorf, April, 1–5, 1975The author thanks Mr. Tatsuro Fukushima for preparation of photographs     

Brain endocast asymmetry in pongids and hominids: Some preliminary findings on the paleontology of cerebral dominance

Observations on petalial asymmetry for 190 hominoid endocasts are reported, and their statistical differences assessed. While all taxa of hominoids show asymmetries to various degrees, the patterns or combinations of petalial asymmetries are very different, with fossil hominids and modern Homo sapiens showing an identical pattern of left-occipital, right-frontal petalias, which contrasts with those found normally in pongids. Of the pongids, Gorilla shows the greater degree of asymmetry in left-occipital petalias. Only modern Homo and hominids (Australopithecus, Homo erectus, Neandertals) show a distinct left-occipital, right-frontal petalial pattern. Analysis by x² statistics shows the differences to be highly significant. Due to small sample size and incompleteness of endocasts, small-brained hominids, i.e., Australopithecus, are problematical. To the degree that gross petalial patterns are correlated with cognitive task specialization, we speculate that human cognitive patterns evolved early in hominid evolution and were related to selection pressures operating on both symbolic and spatiovisual integration, and that these faculties are corroborated in the archaeological record.     

Brain Micro vessel 12-Hydroxyeicosatetraenoic Acid Is the (S) Enantiomer and Is Lipoxygenase Derived

12-Hydroxyeicosatetraenoic acid (12-HETE) production from arachidonic acid by cerebral microvessels isolated from perfused adult murine brain was reduced by the lipoxygenase inhibitors baicalein, esculetin, gossypol, nordihydroguaiaretic acid, and quercetin. Except for quercetin and gossypol, the IC50 did not exceed 10 microM. Each inhibitor, except baicalein, also decreased microvessel prostaglandin production when present in concentrations above their IC50 value for 12-HETE. In contrast, inhibitors of the cytochrome P450 monooxygenase system, clotrimazole, metyrapone, and proadifen (SKF-525A), had little effect on microvessel 12-HETE production. Chiral phase HPLC analysis revealed that only the (S) enantiomer of 12-HETE was formed. The major microvessel metabolite of eicosapentaenoic acid co-eluted with 12-hydroxyeicosapentaenoic acid (12-HEPE) on reverse-phase HPLC and the (S) enantiomer of 12-HEPE on chiral phase HPLC. Furthermore, like 12-HETE, 12-HEPE production was blocked by lipoxygenase inhibitors. These studies demonstrate that brain microvessels produce only the (S) enantiomeric 12-hydroxy derivatives of both arachidonic acid and eicosapentaenoic acid by the action of a lipoxygenase that can be selectively inhibited by baicalein. Since arachidonic acid and eicosapentaenoic acid are available to cerebral blood vessels in certain pathological settings, these 12-hydroxy acid lipoxygenase products may mediate some of the cerebrovascular dysfunction that occurs following stroke, brain trauma, or seizures.     

Cerebral Cortex Ammonia and Glutamine Metabolism During Liver Insufficiency-Induced Hyperammonemia in the Rat

Hyperammonemia has been suggested to induce enhanced cerebral cortex ammonia uptake, subsequent glutamine synthesis and accumulation, and finally net glutamine release into the blood stream, but this has never been confirmed in liver insufficiency models. Therefore, cerebral cortex ammonia- and glutamine-related metabolism was studied during liver insufficiency-induced hyperammonemia by measuring plasma flow and venous-arterial concentration differences of ammonia and amino acids across the cerebral cortex (enabling estimation of net metabolite exchange), 1 day after portacaval shunting and 2, 4, and 6 h after hepatic artery ligation (or in controls). The intra-organ effects were investigated by measuring cerebral cortex tissue ammonia and amino acids 6 h after liver ischemia induction or in controls. Arterial ammonia and glutamine increased in portacaval-shunted rats versus controls, and further increased during liver ischemia. Cerebral cortex net ammonia uptake, observed in portacaval-shunted rats, increased progressively during liver ischemia, but net glutamine release was only observed after 6 h of liver ischemia. Cerebral cortex tissue glutamine, gamma-aminobutyric acid, most other amino acids, and ammonia levels were increased during liver ischemia. Glutamate was equally decreased in portacaval-shunted and liver-ischemia rats. The observed net cerebral cortex ammonia uptake, cerebral cortex tissue ammonia and glutamine accumulation, and finally glutamine release into the blood suggest that the rat cerebral cortex initially contributes to net ammonia removal from the blood during liver insufficiency-induced hyperammonemia by augmenting tissue glutamine and ammonia pools, and later by net glutamine release into the blood. The changes in cerebral cortex glutamate and gamma-aminobutyric acid could be related to altered ammonia metabolism.     

The Binding Properties of the Particulate and Solubilized Sulfonylurea Receptor from Cerebral Cortex Are Modulated by the Mg2+ Complex of ATP

Glibenclamide closes an ATP-sensitive K+ channel (K-ATP channel) by interaction with the sulfonylurea receptor in the plasma membrane of pancreatic B cells and thereby initiates insulin release. Previous studies demonstrated that the Mg2+ complex of ATP decreases glibenclamide binding to the sulfonylurea receptor from pancreatic islets. The aim of the present study was to examine the effect of adenine and guanine nucleotides on binding of sulfonyl-ureas to the cerebral sulfonylurea receptor. For this purpose, binding properties of the particulate and solubilized site from rat or pig cerebral cortex were analyzed. Maximum recovery of receptors in detergent extracts amounted to 40-50%. Specific binding of [3H]glibenclamide to the solubilized receptors corresponded well to specific binding to microsomes. In microsomes and detergent extracts, the Mg2+ complexes of ATP, ADP, GTP, and GDP inhibited binding of [3H]glibenclamide. These effects were not observed in the absence of Mg2+. In detergent extracts, Mg-ATP (300 microM) reduced the number of high-affinity sites for [3H]-glibenclamide by 52% and increased the dissociation constant for [3H]glibenclamide by eightfold; Mg-ATP was half-maximally effective at 41 microM. Alkaline phosphatase accelerated the reversal of Mg-ATP-induced inhibition of [3H]glibenclamide binding. The data suggest similar control of the sulfonylurea receptor from brain and pancreatic islets by protein phosphorylation.     

Amino Acid Neurotransmitter Receptor Changes in Cerebral Cortex in Alcoholism: Effect of Cirrhosis of the Liver

Gamma-aminobutyric acidA/benzodiazepine receptor binding sites and the N-methyl-D-aspartate subclass of glutamate receptor sites were assessed in synaptic plasma membrane homogenates of cerebral cortex tissue obtained at autopsy from cirrhotic and noncirrhotic alcoholic patients and matched control subjects. The alcoholic patients consumed an average of greater than 80 g of ethanol/day, the control subjects less than 20 g/day. Postmortem delays up to approximately 100 h caused no significant loss of any of the binding sites; the patient and subject groups were closely matched for age. The affinities (KD) of the receptor sites did not differ between the patient and subject groups, nor between cortical regions. Using three different radioligands ([3H]muscimol, [3H]flunitrazepam, and [3H]diazepam), the gamma-aminobutyric acidA/benzodiazepine receptor complex was found to have greater density (Bmax) in superior frontal gyrus in alcoholic patients (which selectively shows morphological change in alcoholic patients), but was unchanged in motor cortex. Alcoholic patients with cirrhosis had much less pronounced changes. The density of the N-methyl-D-aspartate subclass of glutamate receptors, assessed with [3H]MK-801, did not vary across patient and subject groups.     

Comparison of Rates of Local Cerebral Glucose Utilization Determined with Deoxy[l-14C]glucose and Deoxy[6-14C]glucose

The activity of the pentose phosphate shunt pathway in brain is thought to be linked to neurotransmitter metabolism, glutathione reduction, and synthetic pathways requiring NADPH. There is currently no method available to assess flux of glucose through the pentose phosphate pathway in localized regions of the brain of conscious animals in vivo. Because metabolites of deoxy[1-14C]glucose are lost from brain when the experimental period of the deoxy[14C]glucose method exceeds 45 min, the possibility was considered that the loss reflected activity of this shunt pathway and that this hexose might be used to assay regional pentose phosphate shunt pathway activity in brain. Decarboxylation of deoxy[1-14C]glucose by brain extracts was detected in vitro, and small quantities of 14C were recovered in the 6-phosphodeoxygluconate fraction when deoxy[14C]glucose metabolites were isolated from freeze-blown brains and separated by HPLC. Local rates of glucose utilization determined with deoxy[1-14C]glucose and deoxy[6-14C]glucose were, however, similar in 20 brain structures at 45, 60, 90, and 120 min after the pulse, indicating that the rate of loss of 14CO2 from deoxy[1-14C]glucose-6-phosphate in normal adult rat brain is too low to permit assay pentose phosphate shunt activity in vivo. Further metabolism of deoxy[1-14]glucose-6-phosphate via this pathway does not interfere during routine use of the deoxyglucose method or explain the progressive decrease in calculated metabolic rate when the experimental period exceeds 45 min.     

An analog of ACTH/MSH (4–9), ORG-2766, reduces cerebral uptake of morphine

The uptake of morphine was significantly reduced in most regions of the brains of conscious, unrestrained rats within 10 minutes after treatment with an analog of ACTH/MSH (4–9), ORG-2766. The effect was most obvious in regions with significant densities of enkephalin receptors, namely basal ganglia, hippocampus and cortex. The results explain, in part, how some fragments and analogs of ACTH/MSH may antagonize behavioral actions of morphine, even though some of these peptides lack significant opiate receptor binding properties. We believe that this effect of ORG-2766 is related to an action on the permeability characteristics of the brain microvasculature. The underlying mechanism is unknown.     

Gastro-intestinal and neurohormonal peptides in the alimentary tract and cerebral complex ofCiona intestinalis (Ascidiaceae)

Summary Polypeptide-hormone producing cells were localized in the alimentary tract and cerebral ganglion ofCiona intestinalis using cytochemical, immunocytochemical and electron-microscopical methods.Antisera to the following peptides of vertebrate type were employed: bombesin, human prolactin (hPRL), bovine pancreatic polypeptide (PP), porcine secretin, motilin, vasoactive intestinal polypeptide (VIP),-endorphin, leu-enkephalin, met-enkephalin, neurotensin, 5-hydroxytryptamin (5-HT), cholecystokinin (CCK), human growth hormone (GH), ACTH, corticotropin-like intermediate lobe peptide (CLIP) and gastric inhibitory peptide (GIP).Immunoreactive cells were found both in the alimentary tract epithelium and in the cerebral ganglion for bombesin, PP, substance P, somatostatin, secretin and neurotensin. Additionally, in the cerebral ganglion only, there were cells immunoreactive for-endorphin, VIP, motilin and human prolactin. 5-HT positive cells, however, were restricted to the alimentary tract.No immunoreactivity was obtained either in the cerebral ganglion or in the alimentary tract with antibodies to leu-enkephalin, met-enkephalin, CCK, growth hormone, ACTH, CLIP and GIP. Prolactin-immunoreactive and pancreatic polypeptide-immunoreactive cells were argyrophilic with the Grimelius' stain and were found in neighbouring positions in the cerebral ganglion.At the ultrastructural level five differently granulated cell types were distinguished in the cerebral ganglion. Granules were present in the perikarya as well as in axons. The possible functions of the peptides as neurohormones, neuroregulators and neuromodulators are discussed.     

Alterations of Phospholipid Metabolism in Rat Cerebral Cortex Mince Induced by Cationic Amphiphilic Drugs

Abstract Cationic amphiphilic drugs (CADs) of varied clinical use were screened to determine their capacity to alter the pattern of labeling with ³²Pj of cerebral cortex mince phospholipids. The altered phospholipid labeling patterns were qualitatively similar, the prominent features being reduced incorporation into phosphatidylcholine and increased incorporation into phosphatidic acid. Relative potencies were: (±)-propranolol > chlorpromazine = 4,4'-bis(diethylaminoethoxy) α,β -diethyldiphenylethane > desipramine > di-bucaine > pimozide > oxymetazoline = fenfluramine = haloperidol = chloroquine > amphetamine = no drug added. Propranolol was used to study the action of CADs further. Its effect was time- and dose-dependent, but in contrast with pineal gland, no label appeared in phosphatidyl-CMP (CDP-diacylglycerol), nor did dialysis of the mince to reduce diffusible substrates or exogenous addition of substrates cause appearance of liponucleotide. Thus lack of diffusible precursors is not responsible for CAD effects in vitro. Pulse-chase experiments with ³²P₁ and [2-³H]glycerol suggested that inhibition of phosphatidate phosphohydrolase may be partly responsible for the observed alterations in phospholipid labeling in the presence of CADs.