Uranyl acetate as an excellent fixative for lipoproteins after electrophoresis on agarose gel

Lózsa, A

doi:10.1016/0009-8981(74)90349-0

Cited by 10 publications

(9 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The silver-intensified sections were processed osmium-free (Phend et al, 1995), so as to avoid oxidation of the SIG particles. The heavy metals used to generate contrast were uranyl acetate, which also served to improve ultrastructural preservation (Terzakis, 1968; Lozsa, 1974) and Reynold’s lead citrate. Vibratome sections were then infiltrated with EMBED-812, flat-embedded between two sheets of Aclar plastic, then ultrathin sectioned at a thickness setting of 70 nm at a cutting plane tangential to the vibratome-cut surface, so as to maximize capture of the EPON-vibratome section surface, where penetration by immunoreagents was maximal.…”

Section: Methodsmentioning

confidence: 99%

α4-GABAA receptors of hippocampal pyramidal neurons are associated with resilience against activity-based anorexia for adolescent female mice but not for males

Chen

Actor-Engel

Aoki

2018

Molecular and Cellular Neuroscience

View full text Add to dashboard Cite

Activity-based anorexia (ABA) is an animal model of anorexia nervosa, a mental illness with highest mortality and with onset that is most frequently during adolescence. We questioned whether vulnerability of adolescent mice to ABA differs between sexes and whether individual differences in resilience are causally linked to α4βδ-GABAR expression. C57BL6/J WT and α4-KO adolescent male and female mice underwent ABA induction by combining wheel access with food restriction. ABA vulnerability was measured as the extent of food restriction-evoked hyperactivity on a running wheel and body weight losses. α4βδ-GABAR levels at plasma membranes of pyramidal cells in dorsal hippocampus were assessed by electron microscopic immunocytochemistry. Temporal patterns and extent of weight loss during ABA induction were similar between sexes. Both sexes also exhibited individual differences in ABA vulnerability. Correlation analyses revealed that, for both sexes, body weight changes precede and thus are likely to drive suppression of wheel running. However, the suppression was during the food-anticipatory hours for males, while for females, suppression was delayed by a day and during food-access hours. Correspondingly, only females adaptively increased food intake. ABA induced up-regulation of α4βδ-GABARs at plasma membranes of dorsal hippocampal pyramidal cells of females, and especially those females exhibiting resilience. Conversely, α4-KO females exhibited greater food restriction-evoked hyperactivity than WT females. In contrast, ABA males did not up-regulate α4βδ-GABARs, did not exhibit genotype differences in vulnerability, and exhibited no correlation between plasmalemmal α4βδ-GABARs and ABA resilience. Thus, food restriction-evoked hyperactivity is driven by anxiety but can be suppressed through upregulation of hippocampal α4βδ-GABARs for females but not for males. This knowledge of sex-related differences in the underlying mechanisms of resilience to ABA indicates that drugs targeting α4βδ-GABARs may be helpful for treating stress-induced anxiety and anorexia nervosa of females but not males.

show abstract

Section: Methodsmentioning

confidence: 99%

α4-GABAA receptors of hippocampal pyramidal neurons are associated with resilience against activity-based anorexia for adolescent female mice but not for males

Chen

Actor-Engel

Aoki

2018

Molecular and Cellular Neuroscience

View full text Add to dashboard Cite

show abstract

“…Subsequently, these sections were processed osmium‐free (Phend et al, ), so as to avoid loss of SIG particles. Sections underwent tissue processing for infiltration with plastic (EMBED‐812, EM Sciences), which included a step of incubating in uranyl acetate (1% in 70% ethanol) to aid in ultrastructural preservation (Terzakis, ; Lozsa, ).…”

Section: Methodsmentioning

confidence: 99%

α4βδ‐GABA_A receptors in dorsal hippocampal CA1 of adolescent female rats traffic to the plasma membrane of dendritic spines following voluntary exercise and contribute to protection of animals from activity‐based anorexia through localization at excitatory synapses

Aoki

Chen

Chowdhury

et al. 2017

J of Neuroscience Research

View full text Add to dashboard Cite

In hippocampal CA1 of adolescent female rodents, α4βδ-GABA receptors (α4βδ-GABA Rs) suppress excitability of pyramidal neurons through shunting inhibition at excitatory synapses. This contributes to anxiolysis of stressed animals. Socially isolated adolescent female rats with 8 days of wheel access, the last 4 days of which entail restricted food access, have been shown to exhibit excessive exercise, choosing to run instead of eat (activity-based anorexia [ABA]). Upregulation of α4βδ-GABA Rs in the dorsal hippocampal CA1 (DH), seen among some ABA animals, correlates with suppression of excessive exercise. We used electron microscopic immunocytochemistry to show that exercise alone (EX), but not food restriction alone (FR), also augments α4βδ-GABA R expression at axospinous excitatory synapses of the DH (67%, P = 0.027), relative to socially isolated controls without exercise or food restriction (CON). Relative to CON, ABA animals' synaptic α4βδ-GABA R elevation was modestly elevated (37%), but this level correlated strongly and negatively with individual differences in ABA vulnerability-i.e., food restriction-evoked hyperactivity (Pearson R = -0.902, P = 0.002) and weight changes (R = 0.822, P = 0.012). These correlations were absent from FR and EX brains or ventral hippocampus of ABA brains. Comparison to CON of α4βδ-GABA R location in the DH indicated that ABA induces trafficking of α4βδ-GABA R from reserve pools in spine cytoplasm to excitatory synapses. Pair-housing CON animals reduced cytoplasmic α4βδ-GABA R without reducing synaptic α4βδ-GABA R. Thus, exercise induces trafficking of α4βδ-GABA Rs to excitatory synapses, while individual differences in ABA vulnerability are linked most strongly to trafficking of α4βδ-GABA Rs in the reverse direction-from excitatory synapses to the reserve pool during co-occurring food restriction. © 2017 Wiley Periodicals, Inc.

show abstract

“…The silver-intensified sections were processed osmium-free (Phend, Rustioni, & Weinberg, 1995), so as to avoid oxidation of the SIG particles. The heavy metals used to generate contrast were uranyl acetate, which also served to improve ultrastructural preservation (Lozsa, 1974; Terzakis, 1968) and Reynold's lead citrate. Vibratome sections were then infiltrated with EMBED-812, flat-embedded between two sheets of Aclar plastic, then ultrathin sectioned at a thickness setting of 70 nm at a cutting plane tangential to the vibratome-cut surface, so as to maximize capture of the EPON-vibratome section surface, where penetration by immunoreagents were maximal.…”

Section: Methodsmentioning

confidence: 99%

Exogenous progesterone exacerbates running response of adolescent female mice to repeated food restriction stress by changing α4-GABAA receptor activity of hippocampal pyramidal cells

et al. 2015

View full text Add to dashboard Cite

Adolescent females are particularly vulnerable to mental illnesses with comorbidity of anxiety, such as anorexia nervosa (AN). We used an animal model of AN, called activity-based anorexia (ABA), to investigate the neurobiological basis of vulnerability to repeated, food restriction (FR) stress-evoked anxiety. Twenty-one of 23 adolescent female mice responded to the 1st FR with increased wheel running activity (WRA), even during the limited period of food access, thereby capturing AN's symptoms of voluntary FR and over-exercise. Baseline WRA was an excellent predictor of FR-elicited WRA (severity of ABA, SOA), with high baseline-runners responding to FR with minimal SOA (i.e., negative correlation). Nine gained resistance to ABA following the 1st FR. Even though allopregnanolone (3α-OH-5α-pregnan-20-one, THP), the metabolite of progesterone (P4), is a well-recognized anxiolytic agent, subcutaneous P4 to these ABA-resistant animals during the 2nd FR was exacerbative, evoking greater WRA than the counterpart resistant group that received oil vehicle, only. Moreover, P4 had no WRA-reducing effect on animals that remained ABA-vulnerable. To explain the sensitizing effect of P4 upon the resistant mice, we examined the relationship between P4 treatment and levels of the α4 subunit of GABAARs at spines of pyramidal cells of the hippocampal CA1, a parameter previously shown to correlate with resistance to ABA. α4 levels at spine membrane correlated strongly and negatively with SOA during the 1st ABA (prior to P4 injection), confirming previous findings. α4 expression levels were greater among P4-treated animals that had gained resistance than of vehicle-treated resistant animals or of the vulnerable animals with or without P4. We propose that α4-GABAARs play a protective role by counterbalancing the ABA-induced increase in excitability of CA1 pyramidal neurons, and although exogenous P4's metabolite, THP, enhances α4 expression, especially among those that can gain resistance, it also interferes with α4-GABAARs’ protective role by desensitizing α4-GABAARs.

show abstract

Uranyl acetate as an excellent fixative for lipoproteins after electrophoresis on agarose gel

Cited by 10 publications

References 11 publications

α4-GABAA receptors of hippocampal pyramidal neurons are associated with resilience against activity-based anorexia for adolescent female mice but not for males

α4-GABAA receptors of hippocampal pyramidal neurons are associated with resilience against activity-based anorexia for adolescent female mice but not for males

α4βδ‐GABA_A receptors in dorsal hippocampal CA1 of adolescent female rats traffic to the plasma membrane of dendritic spines following voluntary exercise and contribute to protection of animals from activity‐based anorexia through localization at excitatory synapses

Exogenous progesterone exacerbates running response of adolescent female mice to repeated food restriction stress by changing α4-GABAA receptor activity of hippocampal pyramidal cells

Contact Info

Product

Resources

About

Uranyl acetate as an excellent fixative for lipoproteins after electrophoresis on agarose gel

Cited by 10 publications

References 11 publications

α4-GABAA receptors of hippocampal pyramidal neurons are associated with resilience against activity-based anorexia for adolescent female mice but not for males

α4-GABAA receptors of hippocampal pyramidal neurons are associated with resilience against activity-based anorexia for adolescent female mice but not for males

α4βδ‐GABAA receptors in dorsal hippocampal CA1 of adolescent female rats traffic to the plasma membrane of dendritic spines following voluntary exercise and contribute to protection of animals from activity‐based anorexia through localization at excitatory synapses

Exogenous progesterone exacerbates running response of adolescent female mice to repeated food restriction stress by changing α4-GABAA receptor activity of hippocampal pyramidal cells

Contact Info

Product

Resources

About

α4βδ‐GABA_A receptors in dorsal hippocampal CA1 of adolescent female rats traffic to the plasma membrane of dendritic spines following voluntary exercise and contribute to protection of animals from activity‐based anorexia through localization at excitatory synapses