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PubMedDate not supplied

Apolipoprotein E-immunoreactivity in aged rhesus monkey cortex: colocalization with amyloid plaques.

In the present study, we examined the relationship between ApoE and amyloid containing profiles within the cerebral cortex of young, middle aged, and aged Rhesus monkeys. Polymerase chain reaction analysis revealed a pattern consistent with the ApoE e4 phenotype in the rhesus monkey similar to that reported in humans. We found numerous ApoE immunoreactive plaques within the temporal neocortex and amygdala, whereas the hippocampus contained only a few such plaques. Although virtually all ApoE-immunoreactive plaques coexpressed beta-amyloid, most plaques were beta A4 positive/ApoE immunonegative within the aged monkey cortex. Moreover, we observed a close correspondence between ApoE and thioflavin-positive (i.e., amyloid) plaques suggesting that ApoE may play a critical role in the conversion of beta A4 to its beta-pleated form. Because ApoE, beta A4 and amyloid are expressed in plaques within the aged Rhesus macaque cortex, this species may provide an in vivo model for investigations aimed at clarifying the interactions between these proteins in normal and pathologic aging.

Aging↗

PubMedDate not supplied

Glycogen synthase kinase 3 alpha and 3 beta do not colocalize with neurofibrillary tangles.

Glycogen synthase kinase (GSK) 3 alpha and 3 beta are two proline-directed serine/ threonine kinases that have been shown in vitro to hyperphosphorylate tau, and therefore, may contribute to neurofibillary tangle (NFT) formation in Alzheimer's disease (AD). We report here that, in the human hippocampal formation of both control and AD individuals, GSK 3 alpha and 3 beta are immunohistochemically localized to neurons within the presubiculum > CA1, CA3, and CA4 subfields of the hippocampus, layers III > II > IV, V, VI of entorhinal cortex, and occasional neurons in layers III, V, and VI of temporal neocortex. By contrast, NFTs occur primarily in CA1. subiculum, layers II and IV of entorhinal cortex, and layers II, III, and V of temporal neocortex. The presubiculum and other subfields are frequently spared. Thus, localization of GSK 3 alpha and GSK 3 beta does not correspond to the expected pattern of neuronal vulnerability to NFT formation in AD. Interpreted within the limitations of immunohistochemical detection, these results argue against a major role of GSK 3 alpha or GSK 3 beta in NFT formation in AD.

Aged↗

PubMed1994

Colocalization of prolactin and proliferating cell nuclear antigen in the anterior pituitary during estrogen-induced pituitary tumors.

Chronic estrogen treatment induces prolactin (PRL)-secreting pituitary tumors in laboratory animals. To determine earlier events of tumorigenesis, we studied cell proliferation in the pituitary following 7-30 days of estrogen administration in Fischer 344 rats. Immunohistochemical localization of proliferative cells by proliferating cell nuclear antigen (PCNA) staining and lactotropes by PRL staining revealed that estrogen treatment caused a time-dependent increase in the number of proliferative cells and lactotropes. Although the increase in lactotropic cell number paralleled the increase in PCNA-reactive cell number, only approximately 30% of lactotropes reacted simultaneously with the PCNA antibody. These results indicate that a subset population of lactotropes proliferates under the influence of estrogen during tumorigenesis.

Animals↗

PubMed1983

Colocalization of oxytocin and neurophysin-I/II and of vasopressin and neurophysin-III in neurons of the sheep hypothalamus. An immunohistochemical study.

Antisera raised against, oxytocin, vasopressin and ovine neurophysins-I, -II and -III (oN-I, oN-II and oN-III respectively) were used in association with the immunohistochemical procedure to stain neurons of the formalin-fixed sheep hypothalamus. Cells that stain for oxytocin also contain oN-I and oN-II and differ from those that stain for vasopressin and oN-III. The observations support our earlier findings in the sheep that oxytocin- and vasopressin-related events are accompanied by the release of oN-I/II and oN-III respectively.

Animals↗

PubMed1986

Vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivity colocalize with vasopressin-like immunoreactivity in the canine hypothalamo-neurohypophysial neuronal system.

The distribution of vasoactive intestinal peptide (VIP) and peptide histidine isoleucine amide (PHI) was investigated in the canine hypothalamus by immunocytochemistry. VIP- and PHI-like immunoreactive neurons were detected in the magnocellular supraoptic and paraventricular nucleus. These magnocellular VIP- and PHI-producing neurons coexist with vasopressin-like immunoreactivity and send axons to the median eminence and neurohypophysis. These findings may serve as an anatomical basis for studying the function of VIP and PHI on pituitary hormone secretion.

Animals↗

PubMed1988

Colocalization of [3H]muscimol uptake and choline acetyltransferase immunoreactivity in amacrine cells of the cat retina.

High affinity uptake of [3H]muscimol, a gamma-aminobutyric acid (GABA) analogue, followed by autoradiography, labelled practically all amacrine cells which expressed GABA-like immunoreactivity. Hence it is a good marker for putative GABAergic amacrine cells. All amacrine cells, which were stained with antibodies against choline acetyltransferase, a marker for cholinergic neurones, also accumulated [3H]muscimol. This makes it likely that cholinergic amacrine cells of the cat retina are a subpopulation of putative GABAergic amacrine cells.

Animals↗

PubMed1989

Colocalization of NGF receptor immunoreactivity and [3H]GABA uptake activity in developing rat septum/diagonal band neurons in vitro.

Neurons in the septum (SEP) and vertical limb of the diagonal band (vDB) of 6-day-old rats were dissociated and cultured for 3 days. Cells with high affinity uptake mechanism for gamma-aminobutyric acid (GABA) were identified autoradiographically using 16 nM [3H]GABA. Cells that expressed nerve growth factor (NGF) receptor immunoreactivity were identified immunocytochemically using MC192, a monoclonal antibody against NGF receptor. Double labeling experiments combining [3H]GABA uptake with immunostaining for NGF receptor showed that 46% of the NGF receptor-immunoreactive cells accumulated [3H]GABA. The result was discussed in relation to a possible involvement of the developing septal GABAergic neurons in NGF-induced neuronal survival.

Animals↗

PubMed1990

Effects of dopamine autoreceptor stimulation on the release of colocalized transmitters: in vivo release of dopamine and neurotensin from rat prefrontal cortex.

The in vivo release of dopamine and neurotensin from the rat medial prefrontal cortex was studied using perfusion microdialysis coupled with sensitive radioimmunoassay and HPLC techniques. Following stimulation of dopamine autoreceptors with either apomorphine (30 micrograms/kg, s.c.) or EMD-23448 (10 microM in the perfusion buffer) a decrease in dopamine and an increase in neurotensin release was observed. The release of both substances was measured in the same dialysis sample. These data suggest that activation of dopamine autoreceptors in the prefrontal cortex produces opposing effects on the release of dopamine and neurotensin.

Animals↗

PubMed1992

Immunohistochemical colocalization of tyrosine hydroxylase and estradiol receptors in the sheep arcuate nucleus.

In sheep, the arcuate nucleus contains numerous tyrosine hydroxylase (TH) and estradiol receptor (rE2) immunoreactive (IR) perikarya and it has been shown previously in this species that catecholaminergic neurons can mediate the gonadal steroid action on the reproductive function. In the present study, double immunohistochemical labelling with antibodies against TH and rE2 have been used to demonstrate the presence of rE2 in TH-IR neurons in the arcuate nucleus where the distribution of TH-IR and rE2-IR neurons overlap each other. Only less than 10% of all the rE2-IR perikarya presented TH immunoreactivity. It was therefore hypothesized that either such a low number of double labelled neurons can support the effects of estradiol in this area or that the effect of this steroid was indirect. In the latter case it might be first mediated by beta-endorphin neurons which have been previously described in this nucleus.

Animals↗

PubMed1992

Neuropeptide FF is colocalized with catecholamine-synthesizing enzymes in neurons of the nucleus of the solitary tract.

Neuropeptide FF (NFF) is an amidated octapeptide of bovine origin. It has some antiopioid-like effects and it elevates blood pressure when injected intravenously in rats. NFF-immunoreactive nerve cells and terminals are localized in large numbers in the dorsomedial caudal brainstem which is a region involved in central regulation of blood pressure. We compared the localization of NFF-immunoreactive neurons with medullary catecholamine-synthesizing neurons by using immunohistochemical double-labeling and light microscopic mirror methods. NFF and tyrosine hydroxylase coexisted in a minor portion of the NFF neurons in the nucleus of the solitary tract and occasional cell bodies were stained with both NFF and PNMT (phenylethanolamine N-methyltransferase) antisera. The results have anatomical correlation with previous pharmacological reports, suggesting that NFF is present in neuronal systems involved in cardiovascular reflex arcs.

Animals↗

PubMed1992

Nitric oxide synthase and GABA colocalize in lamina II of rat spinal cord.

A dense plexus of fibers in the substantia gelatinosa contains nitric oxide synthase (NOS). Using electron microscopic double-labeling immunocytochemistry for NOS combined with GABA or glutamate, we find that all NOS-positive terminals in this region also contain GABA but are not enriched in glutamate. In an attempt to verify that NOS-positive terminals do not originate from primary afferents, we combined NOS immunocytochemistry with anterograde tracing from the sciatic nerve. An intrinsic spinal origin for the NOS-positive plexus is suggested. The results are discussed in the light of the possible involvement of nitric oxide in hyperalgesia.

Afferent Pathways↗

PubMed1992

Colocalization of receptors for vasoactive peptides on astrocytes of cultured rat spinal cord and brain stem: electrophysiological effects of atrial and brain natriuretic peptide, neuropeptide Y and bradykinin.

Electrophysiological studies have been made of the actions of the vasoactive peptides atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), neuropeptide Y (NPY) and bradykinin (BK) on astrocytes in explant cultures of rat brain stem and spinal cord. Addition of ANP, BNP and NPY to the bathing solution at concentrations of 10(-8) and 10(-7) M caused depolarizations of the majority of astrocytes studied, some cells were hyperpolarized and on a small number of cells the peptides had no action. BK (10(-8) M) only induced depolarizations of almost all astrocytes studied. Our electrophysiological data provide strong evidence for the presence of receptors for these vasoactive peptides on astrocytes. When ANP, BNP, NPY and BK were tested on the same cell, all peptides were effective, suggesting a coexistence of peptidergic receptors on astrocytes.

Animals↗

PubMed1993

Colocalization of prolactin- and dynorphin-like substances in a neuronal population of the rat lateral hypothalamus.

Using an antiserum (AS) raised against dynorphin B (DYN B), we revealed immunoreactive neurons in different nuclei of the rat hypothalamus as well as a population of neurons scattered in the lateral areas of the posterior hypothalamus. This population corresponds to that previously shown to be specifically recognized by an ovine prolactin (PRL) AS. Our results suggest that in these neurons, DYN B and PRL AS reacted with different epitopes and that these epitopes could be carried by distinct unidentified peptides.

Animals↗

PubMed1993

Cellular colocalization of calcium/calmodulin-dependent protein kinase II and calcineurin in the rat cerebral cortex and hippocampus.

An immunoperoxidase technique was used to locate multifunctional Ca2+/calmodulin-regulated protein phosphatase (calcineurin) and kinase (CaM-kinase II) in the rat cerebral cortex and hippocampus. Immunoreactivities for both enzymes were highly concentrated in the brain regions, where pyramidal-shaped neurons revealed strong immunoreactivities in their perikarya and dendrites. Serial thin section analysis using the polyethylene glycol embedding procedure disclosed that the cellular distribution of calcineurin immunolabelling in the cerebral cortex and hippocampus was similar to that of CaM-kinase II. The present findings suggest that the phosphatase and kinase may interact with each other in such neuronal subsets.

Animals↗

PubMed1994

Colocalization of prolyl endopeptidase and amyloid beta-peptide in brains of senescence-accelerated mouse.

Prolyl endopeptidase-like immunoreactivity (PEP-LI) was detected and compared with amyloid beta-peptide-like immunoreactivity (A beta-LI) in the brains of senescence-accelerated mouse (SAM). Granular structures of PEP-LI in the hippocampus appeared progressively, and age- and strain-dependently to form deposits which distributed morphologically similar and closely to those of A beta-LI. These results suggest that PEP has functional relevance to amyloidgenesis in brains of SAM.

Aging↗

PubMed1995

Colocalization of NADPH-diaphorase and dopamine beta-hydroxylase in the neuronal somata of the rat kidney.

Neuronal somata in the rat kidney are very often part of ganglionated plexus and contain nitric oxide synthase (NOS). Examining serial 100 microns slices of whole kidneys, we identified three subpopulations of neuronal somata by: (a) staining for NADPH-diaphorase (NADPH-d) histochemistry followed by the demonstration of dopamine beta-hydroxylase (DBH) by immunoperoxidase, and (b) staining for DBH by immunofluorescence followed by the demonstration of NADPH-d histochemical activity. The largest subpopulation of neuronal somata displayed both DBH immunoreactivity and NADPH-d histochemical activity. The second largest group of somata showed NADPH-d activity only. A small group of neuronal somata showed only DBH immunoreactivity. The presence of catecholaminergic characteristics in NOS-containing neuronal somata is unusual and raises the question as to their origin. Their heterogeneity suggests different functions for the different subpopulations.

Adrenergic Fibers↗

PubMed1993

Colocalization of vasoactive intestinal peptide and nitric oxide synthase in neurons of the ferret trachea.

Neurally-mediated relaxation of smooth muscle in human, guinea-pig, cat, and pig airways is largely attributed to a nonadrenergic, noncholinergic mechanism. While the specific transmitter(s) of this relaxant system have not been conclusively identified, vasoactive intestinal peptide and nitric oxide have emerged as likely mediators in airway smooth muscle. Both vasoactive intestinal peptide and nitric oxide relax guinea-pig, pig and human smooth muscle. Vasoactive intestinal peptide is present in nerve fibers associated with airway smooth muscle in humans and several animal species. In guinea-pigs, vasoactive intestinal peptide is released during electrical field stimulation of airway strips and the release correlates with the nonadrenergic relaxation. This relaxation is markedly reduced after incubation of tracheal tissue with a specific VIP antibody and by immunization to vasoactive intestinal peptide. Similarly, nonadrenergic relaxations induced by electrical field stimulation are reduced in human, pig, guinea-pig and bovine airways by nitric oxide synthesis inhibitors. Vasoactive intestinal peptide is present in nerve cell bodies of airway ganglia, suggesting that these nerves in airway smooth muscle originate from intrinsic neurons. It is stored in dense-core vesicles of nerve terminals near airway smooth muscle, suggesting that preformed vasoactive intestinal peptide is released by fusion of the vesicles with the cell membrane of the nerve terminal. Nitric oxide is probably generated by a novel mechanism involving de novo synthesis at the nerve terminal during neural activation by the action of the enzyme nitric oxide synthase.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗

PubMed1995

Somatostatin neurons are a subpopulation of GABA neurons in the rat dentate gyrus: evidence from colocalization of pre-prosomatostatin and glutamate decarboxylase messenger RNAs.

The distribution and extent of glutamate decarboxylase 65 (GAD65) mRNA-labeled neurons that coexpress pre-prosomatostatin mRNA were studied in the rat dentate gyrus of the dorsal and ventral hippocampal formation. The distribution of each group of neurons was determined initially by nonradioactive in situ hybridization experiments with digoxigenin-labeled riboprobes for GAD65 mRNA and pre-prosomatostatin mRNA. Double labeling experiments were then conducted with digoxigenin-labeled riboprobes for GAD65 mRNA and 35S-labeled riboprobes for pre-prosomatostatin mRNA. In the dorsal and ventral dentate gyrus, GAD65 mRNA-containing neurons were highly concentrated in the hilus and in the innermost part of the granule cell layer whereas only a few labeled neurons were scattered in the molecular layer. Pre-prosomatostatin mRNA-containing neurons were primarily located in the hilus and were virtually absent from the molecular and granule cell layers. The simultaneous detection of GAD65 and pre-prosomatostatin mRNAs in the same sections showed that the vast majority of pre-prosomatostatin mRNA-containing neurons in the hilus of the dentate gyrus were also labeled for GAD65 mRNA. In contrast many GAD65 mRNA-labeled neurons did not contain pre-prosomatostatin mRNA. These included all neurons in the molecular layer, neurons within the inner granule cell layer and neurons interspersed amongst double labeled neurons in the hilus. Quantitative analyses indicated that a very high percentage of hilar pre-prosomatostatin mRNA-containing neurons coexpressed GAD65 mRNA in the dorsal (96%) and ventral (92%) dentate gyrus. In contrast only a part of the total population of hilar GAD65 mRNA-containing neurons were also labeled for pre-prosomatostatin mRNA in the dorsal (43%) and ventral (53%) dentate gyrus. In the CA3c region, the percentages of neurons containing both mRNAs were similar to those observed in the hilus. The findings demonstrate that the vast majority of hilar somatostatin neurons, which have previously been shown to be extremely vulnerable to ischemia and seizure-induced damage, are GABA neurons. However, the total population of GAD65 mRNA-containing neurons in the hilus is substantially larger than the somatostatin-containing subgroup, and these findings reinforce the suggestion that GABA neurons are a major component of the diverse group of neurons in the hilus of the dentate gyrus.

Animals↗