Weak if any effect of estrogen on spatial memory in rats

In a number of species, males appear to have spatial abilities that are superior to those of females. The favored explanation for this cognitive difference is hormonal: higher testosterone levels in males than in females. An alternative explanation focuses on the role of varying levels of estrogens in females during the estrus cycle; females perform as well as males on days of low estrogen, but more poorly on days of high estrogen. Other investigators have reported that estrogens improve both types of memory processes, which depend on the striatal (nonspatial navigation) and hippocampal (spatial) memory systems. Additionally, estrogens have been found to protect the working memory. These contradictory results initiated the present study, in which ovariectomized female rats were trained to escape in a Morris water maze. The daily trials were preceded by estradiol application in low doses (Experiment I) or in higher doses (Experiment II). In Experiment I, no differences at all were found between the latencies of the treated and control groups to reach a submerged platform in a Morris water maze. In Experiment II, however, the animals treated with the higher dose of estradiol showed a small deficit in the acquisition of the Morris water maze task. This study indicates that estradiol at around the physiological level has no effect on spatial learning and memory functions

Weak if any effect of estrogen on spatial memory in rats

In a number of species, males appear to have spatial abilities that are superior to those of females. The favored explanation for this cognitive difference is hormonal: higher testosterone levels in males than in females. An alternative explanation focuses on the role of varying levels of estrogens in females during the estrus cycle; females perform as well as males on days of low estrogen, but more poorly on days of high estrogen. Other investigators have reported that estrogens improve both types of memory processes, which depend on the striatal (nonspatial navigation) and hippocampal (spatial) memory systems. Additionally, estrogens have been found to protect the working memory. These contradictory results initiated the present study, in which ovariectomized female rats were trained to escape in a Morris water maze. The daily trials were preceded by estradiol application in low doses (Experiment I) or in higher doses (Experiment II). In Experiment I, no differences at all were found between the latencies of the treated and control groups to reach a submerged platform in a Morris water maze. In Experiment II, however, the animals treated with the higher dose of estradiol showed a small deficit in the acquisition of the Morris water maze task. This study indicates that estradiol at around the physiological level has no effect on spatial learning and memory functions

A zsírsavak allometrikus eloszlásának vizsgálata emlős és madár fajok szöveti foszfolipidjeiben = Investigation of the possible allometric properties of fatty acyl chains in mammalian and avian tissue phospholipids

1. Hat madárfajban (150 g - 20 kg) teszteltük, hogy a teljes tüdő, a tüdő parenchyma és a surfactant teljes foszfolipid (PL) frakcióinak zsírsavprofilja mutat-e allometrikus szabályosságokat. Mindhárom esetben a dokozahexaénsav (DHA) negatív allometrikus összefüggését írtuk le (B = -0.056, -0.17 és -0.1, rendre). A surfactant PL-ekben a palmitinsav negatív allometriát, míg a palmitoleinsav és az arachidonsav ellentétes összefüggést mutatott. A tüdőben és parenchymában negatív testsúlyfüggést igazoltunk a malondialdehid (MDA) koncentrációjában, és pozitív MDA-DHA korrelációt, utalva a DHA lipidperoxidációban betöltött szerepére a madártüdőben. 2. Kilenc emlősfajban (20 g - 500 kg) elemeztük a tüdő PL, az alveoláris surfactant foszfatidilkolin (PC) és szfingomielin (SM) frakcióiban a testsúly- és nyugalmi légzésszámfüggő szabályosságokat. A PL, PC és SM frakciókban az olajsav arány negatívan korrelált a légzésszámmal. A PL-ekben a palmitinsav, a PC-ban a mirisztinsav mutatott pozitív korrelációt. A PL-ekben a mirisztin-, a palmitin-, a palmitolein- és a dokozahexaénsav mutott negatív allometriát, az olajsav pozitív testsúlyfüggést. A surfactant PC frakciójában a palmitinsav negatív, az oljsavnál pozitív allometriát mutatott. Az SM frakció zsírsavprofilja és a lipidperoxidáció mértéke független volt a testsúlytól. A PL-ekben igazolt variabilitás a „membránok mint metabolikus ütemadók” elmélettel egyezik; a surfactant PC frakció összetétele a légzészámmal függött össze. | 1. From 150 g to 20 kg body mass (BM) total lung, lung parenchyma and surfactant phospholipids were tested for allometric properties in 6 gallinaceous species. In all three components docosahexaenoic acid (DHA) showed negative allometric scaling (B = -0.056, -0.17 and -0.1, resp.). Surfactant PLs provided negative allometry for palmitic acid and the opposite was found for palmitoleate and arachidonate. Negative allometry was found for malondialdehyde (MDA) concentration in the native and lavaged lungs, and in these positive MDA-DHA correlation was found, denoting the role of DHA in shaping the allometric properties of in vivo lipid peroxidation. 2. In 9 mammalian species (21.5 g – 503 kg) lung PLs, alveolar surfactant phosphatidylcholine (PC) and sphingomyelin (SM) fatty acyl (FA) chain composition was tested for BM and resting respiratory rate (RRR) associated adaptations. In PL, PC and SM oleic acid provided negative correlations with RRR. Palmitic acid was positively correlated with RRR in PLs, and myristic (C14:0) acid correlated positively with RRR in PCs. In PLs negative allometry was found for myristic, palmitic, palmitoleic acids and DHA, while oleic acid increased allometrically. In surfactant PC FAs palmitic acid provided negative, while oleic acid positive allometry. Surfactant SM and the in vivo lipid peroxidation was species independent. The PL composition varied according to the“membrane pacemakers theory”, while surfactant PC composition was related to RRR

Isolated hypercholesterolemia leads to steatosis in the liver without affecting the pancreas

Abstract Background Lipid accumulation in the liver and pancreas is primarily caused by combined hyperlipidemia. However, the effect of isolated hypercholesterolemia without hypertriglyceridemia is not fully described. Therefore, our aim was to investigate whether hypercholesterolemia alone leads to alterations both in hepatic and pancreatic lipid panel and histology in rats. Methods Male Wistar rats were fed with 2% cholesterol +0.25% cholate-supplemented diet or standard chow for 12 weeks. Blood was collected at weeks 0, 4, 8 and 12 to measure serum cholesterol and triglyceride levels. At week 12, both the pancreas and the liver were isolated for further histological and biochemical analysis. Hepatic and plasma fatty acid composition was assessed by gas chromatography. Expression of mRNA of major enzymes involved in saturated/unsaturated fatty acid synthesis was analyzed by qPCR. In separate experiments serum enzyme activities and insulin levels were measured at week 9. Results At week 12, rats fed with 2% cholesterol +0.25% cholate-supplemented diet were characterized by elevated serum cholesterol (4.09 ± 0.20 vs. 2.89 ± 0.22 mmol/L, *p < 0.05) while triglyceride (2.27 ± 0.05 vs. 2.03 ± 0.03 mmol/L) and glucose levels (5.32 ± 0.14 vs. 5.23 ± 0.10 mmol/L) remained unchanged. Isolated hypercholesterolemia increased hepatic lipid accumulation, hepatic cholesterol (5.86 ± 0.22 vs. 1.60 ± 0.15 ng/g tissue, *p < 0.05) and triglyceride contents (19.28 ± 1.42 vs. 6.78 ± 0.71 ng/g tissue, *p < 0.05), and hepatic nitrotyrosine level (4.07 ± 0.52 vs. 2.59 ± 0.31 ng/mg protein, *p < 0.05). The histology and tissue lipid content of the pancreas was not affected. Serum total protein level, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities remained unchanged in response to isolated hypercholesterolemia while serum alkaline phosphatase activity (ALP) significantly increased. Plasma insulin levels did not change in response to isolated hypercholesterolemia suggesting an intact endocrine function of the pancreas. Isolated hypercholesterolemia caused a significantly increased hepatic and serum fatty acid level associated with a marked alteration of fatty acid composition. Hepatic expression of Δ9-desaturase (SCD1) was increased 4.92×, while expression of Δ5-desaturase and Δ6-desaturase were decreased (0.447× and 0.577×, respectively) due to isolated hypercholesterolemia. Conclusions Isolated hypercholesterolemia leads to hepatic steatosis and marked alterations in the hepatic lipid profile without affecting the pancreas. Altered fatty acid profile might mediate harmful effects of cholesterol in the liver

Evaluation of c-Fos immunoreactivity in the rat brainstem nuclei relevant in migraine pathogenesis after electrical stimulation of the trigeminal ganglion

Migraine is a common neurological condition, causing high disability, but the pathomechanism of the disease is not yet fully understood. Activation of the trigeminovascular system could play a crucial role in the manifestation of the symptoms, but initial step of this activation remains unknown. Functional imaging studies have revealed that certain brainstem areas, referred to as migraine generators, are activated during a migraine attack, including the dorsal raphe, the periaqueductal gray, the locus coeruleus, and the nucleus raphe magnus. However, the studies performed to date have not demonstrated whether this activation is a trigger or a consequence of the migraine attack. With the aim of evaluating the functional relationship between activation of the trigeminal system and migraine generators, we examined the changes in c-Fos immunoreactivity in the above-mentioned nuclei after stimulation of the trigeminal ganglion, an animal model for trigeminovascular activation. The stimulation led to significant increases in the number of c-Fos immunoreactive cells in the nucleus raphe magnus and in the caudal part of the spinal trigeminal nucleus, 2 and 4 h after the stimulation. Activation of the trigeminal system failed to exhibit uniform activation of the brain stem nuclei related to migraine. Our results suggest that the activation of the trigeminal system in the rat by electrical stimulation of the trigeminal ganglion leads to the activation of the descending pain modulatory system, but not to the activation of “migraine generator” nuclei. Therefore, the activity pattern seen in functional studies may reflect a unique feature, exclusively present in migraine