PALIREL, a Computer Program for Analyzing Particle-to-Membrane Relations, with Emphasis on Electron Micrographs of Immunocytochemical Preparations and Gold Labeled Molecules

Ruud, Hans Kristian; Blackstd, T. W.

doi:10.1006/cbmr.1999.1508

Cited by 15 publications

(12 citation statements)

References 30 publications

(15 reference statements)

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“…1.0.2 (i.e., SYNBIN; Fig. 2), on the basis of principles regarding proximity to membranes articulated by Ottersen and colleagues (40,41). Accordingly, the position of each gold particle is determined as it relates to the post-and presynaptic membrane structures.…”

Section: Methodsmentioning

confidence: 99%

Different modes of hippocampal plasticity in response to estrogen in young and aged female rats

Adams

Shah

Janssen

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

207

155

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Estrogen regulates hippocampal dendritic spine density and synapse number in an N-methyl-D-aspartate (NMDA) receptor-dependent manner, and these effects may be of particular importance in the context of age-related changes in endocrine status. We investigated estrogen's effects on axospinous synapse density and the synaptic distribution of the NMDA receptor subunit, NR1, within the context of aging. Although estrogen induced an increase in axospinous synapse density in young animals, it did not alter the synaptic representation of NR1, in that the amount of NR1 per synapse was equivalent across groups. Estrogen replacement in aged female rats failed to increase axospinous synapse density; however, estrogen up-regulated synaptic NR1 compared with aged animals with no estrogen. Therefore, the young and aged hippocampi react differently to estrogen replacement, with the aged animals unable to mount a plasticity response generating additional synapses, yet responsive to estrogen with respect to additional NMDA receptor content per synapse. These findings have important implications for estrogen replacement therapy in the context of aging.A t the turn of the century, the life expectancy of American women was roughly equivalent to the average age of the onset of menopause (1). Presently, there is a 30-year discrepancy between these two demographic indices, with a life expectancy of Ϸ80 years and the average onset of menopause remaining in the early fifties (1). As such, it is critical that we understand the interaction of reproductive senescence with the aging of other systems, particularly the nervous system. The regulation of the reproductive axis by estrogens has been characterized in great detail (2). However, estrogens also impact synaptic communication in brain regions involved in cognitive processing, such as the hippocampus (3), and these effects may be of particular importance in the context of aging when both circulating estrogen levels change and hippocampal-dependent functions decline. With respect to its nonreproductive functions, estrogen improves verbal memory and the capacity for learning new associations in both naturally and surgically menopausal women (4). In rats, although findings are somewhat controversial (5-7), learning was enhanced during the proestrus phase (i.e., high estrogen) of the estrous cycle compared with the estrus phrase (i.e., low estrogen) (8). Another study found improved learning and memory on the Morris water maze task in ovariectomized animals with intrahippocampal estrogen injection compared with saline injection (9).Our current understanding of estrogen effects on synaptic plasticity in the hippocampus is based almost exclusively on data from young animals. For example, dendritic spine density in CA1 pyramidal cells is sensitive to naturally occurring estrogen fluctuations in young animals (10), as well as experimentally induced estrogen depletion and replacement (11)(12)(13)(14). Recent evidence suggests that estrogens mediate these morphological changes through N-methyl-D-...

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Section: Methodsmentioning

confidence: 99%

Different modes of hippocampal plasticity in response to estrogen in young and aged female rats

Adams

Shah

Janssen

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

207

155

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“…6 Particles within 50 nm from the membrane were counted, allowing computation of linear density (number per m) by use of the PALIREL program. 15 Membrane fragments were classified as those facing capillaries or a neighboring myocyte ("nondisk") and as those engaged in intercalated disks, excluding desmosomes and gap junctions ("disk"). Density (particles per m 2 ) of the total number of gold particles within "disk fields," defined as the area delimited by the borders between the dense filamentous masses of fascia adherens and the adjoining myofilaments, was computed with the MORFOREL program.…”

Section: Methodsmentioning

confidence: 99%

“…Density (particles per m 2 ) of the total number of gold particles within "disk fields," defined as the area delimited by the borders between the dense filamentous masses of fascia adherens and the adjoining myofilaments, was computed with the MORFOREL program. 15 3.Lactate transport into cardiomyocytes (CHF, nϭ4 and Sham, nϭ4 rats) was determined in cells loaded with BCECF acetoxymethyl ester (Molecular Probes Inc). 16,17 Between 2 and 5 cells were exposed to alternating (2 Hz) 440-and 490-nm excitation wavelengths (Delta-Scan, Photon Technology International Inc).…”

Section: Methodsmentioning

confidence: 99%

Upregulation of the Cardiac Monocarboxylate Transporter MCT1 in a Rat Model of Congestive Heart Failure

et al. 2001

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Background-Cardiac metabolism becomes more dependent on carbohydrates in congestive heart failure (CHF), and lactate may be used as an important respiratory substrate. Monocarboxylate transporter 1 (MCT1) promotes cotransport of lactate and protons into and out of heart cells and conceivably flux of lactate between cells, because it is abundantly present in the intercalated disk. Methods and Results-Six weeks after induction of myocardial infarction (MI) in Wistar rats, left ventricular end-diastolic pressures were Ͼ15 mm Hg, signifying CHF. MCT1 and connexin43 protein levels in CHF were 260% and 20%, respectively, of those in sham-operated animals (Sham), and the corresponding mRNA signals were 181% and not significantly changed, respectively. Confocal laserscan immunohistochemistry and quantitative immunogold cytochemistry showed that MCT1 density was much higher in CHF than in Sham both at the surface membrane and in the intercalated disk. In CHF, a novel intracellular pool of MCT1 appeared to be associated with cisternae, some close to the T tubules. In contrast, connexin43 particles, seen exclusively at gap junctions, were substantially fewer.

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“…Sub-Synaptic distribution of pLIMK-The immunogold particle density and distribution in various compartments was analyzed using SYNBIN software (Adams et al, 2001c, Adams et al, 2002, Adams et al, 2004, that is based on principles regarding proximity to membranes articulated by Ruud (Ruud and Blackstad, 1999). Accordingly, the position of each gold particle was determined as it relates to the postsynaptic and presynaptic membrane structures.…”

Section: Post-embedding Electron Microscopymentioning

confidence: 99%

Estrogen and aging affect synaptic distribution of phosphorylated LIM kinase (pLIMK) in CA1 region of female rat hippocampus

et al. 2008

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Abstract17β-Estradiol (E) increases axospinous synapse density in the hippocampal CA1 region of young female rats, but not in aged rats. This may be linked to age-related alterations in signaling pathways activated by synaptic estrogen receptor α (ER-α) that potentially regulate spine formation, such as LIM-Kinase (LIMK), an actin depolymerizing factor/cofilin kinase. We hypothesized that, as with ER-α, phospho-LIMK (pLIMK) may be less abundant or responsive to E in CA1 synapses of aged female rats. To address this, cellular and subcellular distribution of pLIMK-immunoreactivity (pLIMK-IR) in CA1 was analyzed by light and electron microscopy in young and aged female rats that were ovariectomized and treated with either vehicle or E. pLIMK-IR was found primarily in perikarya within the pyramidal cell layer and dendritic shafts and spines in stratum radiatum (SR). While pLIMK-IR was occasionally present in terminals, post-embedding quantitative analysis of SR showed that pLIMK had a predominant post-synaptic localization and was preferentially localized within the postsynaptic density (PSD). The percentage of pLIMK-labeled synapses increased (30%) with E treatment (p<0.02) in young animals, and decreased (43%) with age (p<0.002) regardless of treatment. The pattern of distribution of pLIMK-IR within dendritic spines and synapses was unaffected by age or E treatment, with the exception of an E-induced increase in the non-synaptic core of spines in young females. These data suggest that age-related synaptic alterations similar to those seen with ER-α occur with signaling molecules such as pLIMK, and support the hypothesis that age-related failure of E treatment to increase synapse number in CA1 may be due to changes in the molecular profile of axospinous synapses with respect to signaling pathways linked to formation of additional spines and synapses in response to E. NY, 10029. Tel: 212-659-5985, Fax: 212-849-2510, Email: john.morrison@mssm.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. In the female rat hippocampus, dendritic spine density and synapse number in CA1 pyramidal neurons increase when levels of estrogen increase (Gould et al., 1990, Woolley and McEwen, 1992, Woolley et al., 1996, and the size of CA1 spines is also affected by estrogen (Mukai et al., 2007). ER-α and ER-β are both present in these same spines and synapses (Milner et al., 2001, Adams et al., 2002, Milner et al., 2005 and while ER-β also impacts synaptic plasticity in CA1 (Day et al., 2005, Szymczak et al., 2006, the estrogen-induced spinogenesis in CA1 is thought to be mediated primarily b...

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PALIREL, a Computer Program for Analyzing Particle-to-Membrane Relations, with Emphasis on Electron Micrographs of Immunocytochemical Preparations and Gold Labeled Molecules

Cited by 15 publications

References 30 publications

Different modes of hippocampal plasticity in response to estrogen in young and aged female rats

Different modes of hippocampal plasticity in response to estrogen in young and aged female rats

Upregulation of the Cardiac Monocarboxylate Transporter MCT1 in a Rat Model of Congestive Heart Failure

Estrogen and aging affect synaptic distribution of phosphorylated LIM kinase (pLIMK) in CA1 region of female rat hippocampus

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