Distribution of zinedin in the rat brain

Members of the striatin family are scaffolding proteins involved in numerous signaling pathways principally in neurons. Zinedin is the only member of this protein family for which the brain distribution has not been determined so far. Here, we have validated a specific antibody against zinedin and used this tool to study the localization of zinedin at cellular and sub-cellular levels in the rat brain. Zinedin is primarily expressed in neurons of the hippocampus, cerebral cortex, olfactory bulb and caudate putamen nucleus. Like other members of the striatin family, zinedin displays a polarized distribution in the somato-dendritic compartment of neurons and is enriched in dendritic spines. The rostral expression of zinedin as well as its compartmented distribution in dendritic spines may have important implications not only for zinedin function but also in the physiology of dendritic spines of a particular subset of neurons.     

Distribution of beacon immunoreactivity in the rat brain

Beacon is a novel peptide isolated from the hypothalamus of Israeli sand rat. In the present study, we determined the distribution of beacon in the rat brain using immunohistochemical approach with a polyclonal antiserum directed against the synthetic C-terminal peptide fragment (47-73). The hypothalamus represented the major site of beacon-immunoreactive (IR) cell bodies that were concentrated in the paraventricular nucleus (PVN) and the supraoptic nucleus (SON). Additional immunostained cells were found in the septum, bed nucleus of the stria terminalis, subfornical organ and subcommissural organ. Beacon-IR fibers were seen with high density in the internal layer of the median eminence and low to moderate density in the external layer. Significant beacon-IR fibers were also seen in the nucleus of the solitary tract and lateral reticular formation. The beacon neurons found in the PVN were further characterized by double label immunohistochemistry. Several beacon-IR neurons that resided in the medial PVN were shown to coexpress corticotrophin-releasing hormone (CRH) and most labeled beacon fibers in the external layer of median eminence coexist with CRH. The topographical distribution of beacon-IR in the brain suggests multiple biological activities for beacon in addition to its proposed roles in modulating feeding behaviors and pituitary hormone release.     

Distribution of vasopressin and oxytocin in rat brain

Arginine-vasopressin and oxytocin in various portions of rat brain were determined by radioimmunoassays. The hormones were extracted from tissue samples into 0.1 N HCl and then purified partially with acetone-petroleum ether extraction. The non-equilibration method was used for the assays. In this method recovery rates of arginine-vasopressin and oxytocin were 73.0 +/- 4.4% and 75.0 +/- 3.8%, respectively. Sensitivities of the assays were 1 pg of arginine-vasopressin and 0.75 pg (0.3 microU) of oxytocin per assay tube. The higher concentrations of arginine-vasopressin and oxytocin were confirmed in the hypothalamo-neurohypophyseal system, where these hormones are synthesized, transported and stored. Relatively high concentrations of these hormones, especially oxytocin, were detected in spinal cord. Amygdala, hippocampus, limbic forebrain and pineal body contained a certain amount of arginine-vasopressin (2-20 pg/mg protein). Oxytocin (1-7 pg/mg protein) was also detected in amygdala, pons and medulla oblongata, pineal body and midbrain. The low concentrations of these hormones were also found in cerebral cortex and cerebellum.     

Distribution of gastrin and CCK-like peptides in rat brain

Summary The distribution of gastrin and CCK-like peptides in the rat brain was studied by immunocytochemistry using an antiserum reacting equally well with both groups of peptides. Immunoreactive nerve cell bodies were detected in all cortical areas, in the hippocampus where they were particularly numerous, in the mesencephalic central gray and in the medulla oblongata. After colchicine treatment immunoreactive material appeared also in cell bodies of the magnocellular hypothalamic system. Immunoreactive nerve fibers were widely distributed in the brain. Particularly dense accumulations were seen in the hippocampus near the ventral surface of the brain, in the caudate nucleus, in the interpeduncular nucleus, the parabrachial nucleus, the dorsal part of the medulla oblongata and in the dorsal horn of the spinal cord. In the hypothalamus immunoreactive nerve fibers were observed in all nuclei, being most frequent in the ventromedial, dorsal and lateral hypothalamic nuclei. A rich supply of nerve fibers was seen in the outer zone of the median eminence and in the neurohypophysis. From previous immunochemical analysis it appears that the peptide demonstrated in most parts of the brain is identical with CCK-8. In the neurosecretory cell bodies of the hypothalamus, the median eminence and the neurohypophysis, however, the immunoreactive material is probably identical with gastrin.     

Distribution and release of adenosine triphosphate in rat brain

The steady-state level of brain ATP was measured after the tissue had been treated with a focused microwave irradiation system. The brain ATP content (1.50 nmol/mg tissue) obtained by microwave fixation is similar to that observed by others using fast-freezing and microwave fixation techniques. The concentrations of ATP in different brain regions show a rather uniform distribution, ranging from 1.918±0.059 (brainstem) to 2.393±0.19 (caudate) nmol/mg tissue; however, insufficient microwave fixation time seems to produce a greater regional variation of ATP. Release of ATP was investigated by placing a cup on the sensory-motor cortex. The rate for basal release of ATP is 1.43±0.14 femtomole/min/mm². A 30-fold increase in ATP release was obtained by direct stimulation of the cortex with 5 mA pulses of 0.2 msec duration at a rate of 20/sec over a period of 10 min. These results, in conjunction with others describing the potent pharmacological action of the nucleotide, seem to suggest that ATP could be a mediator in a purinergic system in the CNS.     

Distribution of B/K protein in rat brain

B/K protein is a recently isolated member of the double C2-like-domain protein family, which is highly abundant in rat brain. We generated high-titer rabbit polyclonal antibodies with specificity to the 55-kDa rat B/K protein, and examined the expression pattern of B/K protein in rat brain using an immunohistochemical staining method. Immunoreactivity to B/K protein was widely found in distinct regions of rat brain: strongly in the hypothalamus, most of the circumventricular organs, the locus coeruleus, the A5 neurons of the pons, and the anterior pituitary; moderately in the anterior olfactory nucleus, the raphe nucleus, the subfornical organ, and the median eminence; and faintly in the olfactory bulb, the telencephalon, the substantia nigra pars compacta, and the ventral tegmental area. In contrast, immunoreactivity to B/K protein was not observed in the thalamus, the cerebellum, the posterior pituitary, or the spinal cord. In most of the B/K-expressing neurons, immunoreactivity was expressed mainly in soma but not in nerve fibers. B/K was also expressed in nonneuronal cells such as the tanycytes and the subcommissural organ. In the vasopressin-secreting supraoptic and paraventricular nuclei of the hypothalamus, the site where B/K cDNA was originally isolated from, all of the neurons showing vasopressin immunoreactivity also expressed B/K protein, suggesting an overlap of their expression patterns.     

Distribution of NADPH-diaphorase positive cells in the rat brain

1. Recent work suggests that neurones in vivo and in culture which contain neuropeptide Y and somatostatin and which stain positively for the enzyme NADPH-diaphorase may be resistant to excitotoxins. 2. We have therefore examined the distribution of the enzyme throughout the rat brain. 3. Neurones were found intensely or moderately stained at all levels of the neuraxis, but with particularly dense clusters of cells in the periaqueductal grey area and dorsal raphe nucleus of the hindbrain, the pedunculopontine and interpeduncular nuclei, and the dorsal spinal trigeminal nucleus. 4. Intensely stained cells occurred with no clear pattern in neocortical and striatal areas, and in nucleus basalis. 5. The observed distribution of staining is consistent with previous studies in other species of limited regions of the CNS. 6. While no consistent functional or neurochemical correlate of the NADPH-diaphorase distribution could be proposed, the work provides a basis for more detailed investigations of neuronal sensitivity to excitotoxins.     

Distribution of biogenic amines in rat brain with hypothermia

Distribution of catecholamines and serotonin in the thalamus and hypothalamus of the brain was studied as affected by hypothermia. Both single and double hypothermia are found to induce considerable shifts in distribution of these amines. In the both regions of the brain the content of serotonin increases greatly, that of dopamine and adrenaline rises to a less extent. The amount of norepinephrine as compared to the control in unchanged.     

Distribution of ACTH-like immunoreactivity in rat brain and gastrointestinal tract

Summary Immunocytochemistry reveals ACTH-like immunoreactivity to reside not only in the pituitary but also in central nerves and in antral gastrin cells. In all probability, the central nerves store a peptide identical with or closely resembling true ACTH. Their pattern of distribution is, in some regions, similar to that of enkephalin-immunoreactive nerves. The antiserum demonstrating ACTH-like immunoreactivity in central nerves and in antral gastrin cells is directed towards the COOH-terminal part of the hormone. A peptide corresponding to this part, the corticotrophin-like intermediate peptide (CLIP) is manufactured by the pars intermedia of the pituitary. CLIP is devoid of adrenocortical activity but has recently been shown to possess insulin-releasing activity. The occurrence of CLIP-like peptides in antral gastrin cells may indicate a role for such peptides in the gastrointestinal regulation of insulin release. The simultaneous occurrence of enkephalin-like and ACTH-like immunoreactivity in the antral gastrin cells is of particular interest since a large precursor molecule, containing both the enkephalin and the ACTH sequence has recently been identified.     

Distribution of beta-endorphin-related peptides in rat pituitary and brain.

beta-Endorphin, the most potent known naturally occurring analgesic agent, is found in pituitary and brain in company with a series of structurally and biosynthetically related peptides that are essentially devoid of opiate activity. In studies of beta-endorphin it is important to discriminate between the active and inactive forms of the peptide. This review describes the use of chemical and immunological methods for localizing the peptides in the tissues, extracting and resolving the peptides by chromatography, and determining the concentrations of the peptides by radioimmunoassay. These approaches have allowed the distribution of beta-endorphin and its related peptides to be assigned unequivocally in regions of rat pituitary and brain. It has been found that the multifunctional corticotropin-endorphin prohormone can undergo processing by different mechanisms in different tissues, permitting the intrinsic activities of its fragments to be expressed selectively. The different processing patterns can be attributed to the existence of highly specific enzymes, characteristic of individual cells, which regulate the formation of this potent opiate.     

Morphine formation from codeine in rat brain: a possible mechanism of codeine analgesia

The O-demethylation of codeine to morphine was demonstrated in rat brain homogenate. Maximal formation occurred at 10 minutes, with a Vmax of 5.93 +/- 0.16 nmol/g brain/h and Km of 37.82 +/- 4.99 microM. The formation was significantly (P less than 0.05) greater in the microvessel-rich brain fraction. Intraperitoneal injection of codeine in the rat resulted in brain concentrations of morphine which could not be solely attributed to transfer of morphine from the blood stream across the blood-brain barrier. Morphine formed in the brain after codeine administration may be an important mechanism for codeine-induced analgesia.     

Distribution of protein kinase activities in subcellular fractions of rat brain

The subcellular distribution of histone and phosvitin kinase activities in brain has been studied and the ability of the various fractions to catalyse the phosphorylation of their endogenous proteins (intrinsic protein kinase activity) also examined. Synaptosome membrane fragments have little or no histone or phosvitin kinase activity but contain the highest concentration of cyclic AMP-stimulated intrinsic protein kinase activity. Homogenisation of the membrane fragments in Triton X-100 increased the histone kinase activity but on centrifugation it was all recovered in the supernatant, while the insoluble material contained all the intrinsic protein kinase activity. These results indicate that the intrinsic protein kinase activity of cerebral membrane fragments is due to the presence of a kinase enzyme which is specific to certain membrane proteins. The intrinsic protein kinase activity of synaptosome membrane fragments is a rather slow reaction which takes several minutes to saturate all the acceptor proteins.     

Distribution and properties of aldehyde dehydrogenase in regions of rat brain

Abstract: NAD-dependent aldehyde dehydrogenases (EC 1.2.1.3) were isolated from various subcellular organelles as well as from different regions of rat brain. The mitochondrial, microsomal, and cytosolic fractions were found to contain 40%, 28%, and 12%, respectively, of the total aldehyde dehydrogenase (5.28 ± 0.44 nmol NADH/min/g tissue) found in rat brain homogenate when assayed with 70 μ. M propionaldehyde at pH 7.5. The total activity increased to 17.3 ± 2.7 nmol NADH/min/g tissue when assayed with 5 m M propionaldehyde. Under these conditions the three organelles contained 49%, 23%, and 9%, respectively, of the activity. The enzyme isolated from cytosol possessed the lowest K _m. The molecular weight of the enzyme isolated from all three subcellular organelles was ∼100,000. Four activity bands were found by electrophoresis of crude homogenates, isolated mitochondria, or microsomes on cellulose acetate strips. Cytosol possessed just two of the forms. The total activity was essentially the same in homogenates obtained from cortex, subcortex, pons-medulla, or cerebellum. Further, the enzyme had the same molecular distribution and total activity in each of these four brain regions. Disulfiram was found to be an in vivo and in vitro inhibitor of the enzymes obtained from these brain regions. Mercaptoethanol, required for the stability of the enzyme, reversed the inhibition produced by disulfiram. The effect was greater for enzyme isolated from cytosol than from mitochondria. Calculations led to the prediction that aldehydes such as acetaldehyde are oxidized in cytosol.     

Distribution of ACTH-like immunoreactivity in rat brain and gastrointestinal tract.

Immunocytochemistry reveals ACTH-like immunoreactivity to reside not only in the pituitary but also in central nerves and in central nerves and in antral gastrin cells. In all probability, the central nerves store a peptide identical with or closely resembling true ACTH. Their pattern of distribution is, in some regions, similar to that of enkephalin-immunoreactive nerves. The antiserum demonstrating ACTH-like immunoreactivity in central nerves and in antral gastrin cells is directed towards the COOH-terminal part of the hormone. A peptide corresponding to this part, the corticotrophin-like intermediate peptide (CLIP) is manufactured by the pars intermedia of the pituitary. CLIP is devoid of adrenocortical activity, but has recently been shown to possess insulin-releasing activity. The occurrence of CLIP-like peptides in antral gastrin cells may indicate a role for such peptides in the gastrointestinal regulation of insulin release. The simultaneous occurrence of enkephalin-like and ACTH-like immunoreactivity in the antral gastrin cells is of particular interest since a large precursor molecule, containing both the enkephalin and the ACTH sequence has recently been identified.     

Distribution of transferrin synthesis in brain and other tissues in the rat

Levels of transferrin mRNA were measured by hybridization to transferrin cDNA in extracts from various areas of rat brain and other tissues. The highest concentrations of transferrin mRNA were found in the liver and the choroid plexus of the lateral and third ventricles. Lower concentrations were observed in the medulla and thalamus, choroid plexus of the fourth ventricle, cortex, hypothalamus, cerebellum, pituitary, testis, placenta, stomach, spleen, kidney, muscle, and heart. Yolk sac, small intestine, and adrenal glands did not contain detectable transferrin mRNA levels. The size of transferrin mRNA was the same in liver, brain, and testis. Upon incubation of choroid plexus pieces with [14C]leucine in vitro, about 4% of the radioactive protein secreted into the medium was found to be transferrin. Together with previous data (Dickson, P.W., Howlett, G.J., and Schreiber, G. (1985) J. Biol. Chem. 260, 8214-8219; Dickson, P.W., Aldred, A.R., Marley, P.D., Bannister, D., and Schreiber (1986) J. Biol. Chem. 261, 3475-3478) the obtained data suggest that the choroid plexus plays a role in maintenance of homeostasis in the microenvironment of the central nervous system by synthesizing and secreting plasma proteins.     

Distribution of estramustine-binding protein during postnatal development of rat brain

Estramustine-binding protein (EMBP) is expressed in several types of brain tumors, such as astrocytoma, ependymoma, and meningioma. It binds the cytotoxic drug estramustine with high affinity and is suggested to cause accumulation of the drug in EMBP-expressing tumor cells. In this study, the spatial distribution of EMBP in normal rat brain was studied with immunohistochemistry. Brains from male and female rats of different ages were used. EMBP was found in the cytoplasm of ependymal cells, in the leptomeninges, mainly the arachnoid, and in scattered neurons. Moreover, staining was seen in nuclei of choroid plexus cells, in the granular cell layer in the cerebellum, and in a few scattered endothelial cells. The nuclear staining was more frequent in younger animals. No obvious difference in EMBP expression between male and female rats was observed. The expression of EMBP in rat brain was confirmed with nested RT-PCR. Future studies are justified to elucidate the role of EMBP-like proteins in CNS and in brain tumors.     

Distribution of aluminum in different brain regions and body organs of rat

In the present study, an attempt has been made to investigate the distribution of aluminum in different regions of brain and body organs of male albino rats, following subacute and acute aluminum exposure. Aluminum was observed to accumulate in all regions of the brain with maximum accumulation in the hippocampus. Subcellular distribution of aluminum indicated that there was maximum localization in the nucleus followed by cytosolic, microsomal, and mitochondrial deposition. Elution profile of cytosolic proteins on G-75 Sephadex column revealed a substantial amount of aluminum bound to high-mol-wt protein fraction. Aluminum was also seen to compartmentalize in almost all the tissues of the body to varying extents, and the highest accumulation was in the spleen.