scholarly journals Fluoxetine Dose and Administration Method Differentially Affect Hippocampal Plasticity in Adult Female Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jodi L. Pawluski ◽  
Eva van Donkelaar ◽  
Zipporah Abrams ◽  
Virginie Houbart ◽  
Marianne Fillet ◽  
...  
Keyword(s):  
Adult Female ◽  
Female Rats ◽  
Granule Cell Layer ◽  
Female Rat ◽  
Sprague Dawley ◽  
Osmotic Minipump ◽  
Hippocampal Plasticity ◽  
Fluoxetine Treatment ◽  
Administration Method ◽  
Administration Methods

Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately, administration of antidepressant medications in rodent models is often through injection, oral gavage, or minipump implant, all relatively stressful procedures. The aim of the present study was to investigate how administration of the commonly used SSRI, fluoxetine, via a wafer cookie, compares to fluoxetine administration using an osmotic minipump, with regards to serum drug levels and hippocampal plasticity. For this experiment, adult female Sprague-Dawley rats were divided over the two administration methods: (1) cookie and (2) osmotic minipump and three fluoxetine treatment doses: 0, 5, or 10 mg/kg/day. Results show that a fluoxetine dose of 5 mg/kg/day, but not 10 mg/kg/day, results in comparable serum levels of fluoxetine and its active metabolite norfluoxetine between the two administration methods. Furthermore, minipump administration of fluoxetine resulted in higher levels of cell proliferation in the granule cell layer (GCL) at a 5 mg dose compared to a 10 mg dose. Synaptophysin expression in the GCL, but not CA3, was significantly lower after fluoxetine treatment, regardless of administration method. These data suggest that the administration method and dose of fluoxetine can differentially affect hippocampal plasticity in the adult female rat.

Infarct size is increased in female post-MI rats treated with rapamycin

2009 ◽  
Vol 87 (6) ◽  
pp. 460-470 ◽  
Author(s):  
Claude Lajoie ◽  
Viviane El-Helou ◽  
Cindy Proulx ◽  
Robert Clément ◽  
Hugues Gosselin ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Female Rats ◽  
Coronary Artery Ligation ◽  
Female Rat ◽  
Sprague Dawley ◽  
Ischemic Insult ◽  
Fibrotic Response ◽  
Artery Ligation ◽  
Sprague Dawley Rats ◽  
Scar Healing

Rapamycin represents a recognized drug-based therapeutic approach to treat cardiovascular disease. However, at least in the female heart, rapamycin may suppress the recruitment of putative signalling events conferring cardioprotection. The present study tested the hypothesis that rapamycin-sensitive signalling events contributed to the cardioprotective phenotype of the female rat heart after an ischemic insult. Rapamycin (1.5 mg/kg) was administered to adult female Sprague–Dawley rats 24 h after complete coronary artery ligation and continued for 6 days. Rapamycin abrogated p70S6K phosphorylation in the left ventricle of sham rats and the noninfarcted left ventricle (NILV) of 1-week postmyocardial-infarcted (MI) rats. Scar weight (MI 0.028 ± 0.006, MI+rapamycin 0.064 ± 0.004 g) and surface area (MI 0.37 ± 0.08, MI+rapamycin 0.74 ± 0.03 cm2) were significantly larger in rapamycin-treated post-MI rats. In the NILV of post-MI female rats, rapamycin inhibited the upregulation of eNOS. Furthermore, the increased expression of collagen and TGF-β3 mRNAs in the NILV were attenuated in rapamycin-treated post-MI rats, whereas scar healing was unaffected. The present study has demonstrated that rapamycin-sensitive signalling events were implicated in scar formation and reactive fibrosis. Rapamycin-mediated suppression of eNOS and TGF-β3 mRNA in post-MI female rats may have directly contributed to the larger infarct and attenuation of the reactive fibrotic response, respectively.

scholarly journals Greater natriuretic response to ENaC inhibition in male versus female Sprague-Dawley rats

2020 ◽  
Vol 318 (2) ◽  
pp. R418-R427 ◽  
Author(s):  
Reham H. Soliman ◽  
Jermaine G. Johnston ◽  
Eman Y. Gohar ◽  
Crystal M. Taylor ◽  
David M. Pollock
Keyword(s):  
Protein Expression ◽  
Time Of Day ◽  
Female Rats ◽  
Female Rat ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Endothelin System ◽  
Males And Females ◽  
Epithelial Sodium Channel Enac

Genes for the epithelial sodium channel (ENaC) subunits are expressed in a circadian manner, but whether this results in time-of-day differences in activity is not known. Recent data show that protein expression of ENaC subunits is higher in kidneys from female rats, yet females are more efficient in excreting an acute salt load. Thus, our in vivo study determined whether there is a time-of-day difference as well as a sex difference in the response to ENaC inhibition by benzamil. Our results showed that the natriuretic and diuretic responses to a single dose of benzamil were significantly greater in male compared with female rats whether given at the beginning of the inactive period [Zeitgeber time 0 (ZT0), 7 AM] or active period (ZT12, 7 PM). However, the response to benzamil was not significantly different between ZT0 and ZT12 dosing in either male or female rats. There was no difference in renal cortical α-ENaC protein abundance between ZT0 and ZT12 or males and females. Given previous reports of flow-induced stimulation of endothelin-1 (ET-1) production and sex differences in the renal endothelin system, we measured urinary ET-1 excretion to assess the effects of increased urine flow on intrarenal ET-1. ET-1 excretion was significantly increased following benzamil administration in both sexes, but this increase was significantly greater in females. These results support the hypothesis that ENaC activity is less prominent in maintaining Na+ balance in females independent of renal ET-1. Because ENaC subunit genes and protein expression vary by time of day and are greater in female rat kidneys, this suggests a clear disconnect between ENaC expression and channel activity.

N-(3,5-dinitrophenyl)-5-methoxytryptamine, a novel melatonin antagonist: effects on sexual maturation of the male and female rat and on oestrous cycles of the female rat

1988 ◽  
Vol 116 (1) ◽  
pp. 43-53 ◽  
Author(s):  
M. Laudon ◽  
Z. Yaron ◽  
N. Zisapel
Keyword(s):  
Drinking Water ◽  
Adult Female ◽  
Sexual Maturation ◽  
Young Male ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Simultaneous Administration ◽  
Serum Concentrations ◽  
The Brain

ABSTRACT N-(3,5-dinitrophenyl)-5-methoxytryptamine (ML-23) has recently been synthesized and shown to antagonize the inhibitory effect of melatonin on the release of dopamine in vitro from the hypothalamus of female rats. In the present study the ability of ML-23 to inhibit in vivo the following melatonin-mediated effects was investigated: (1) delayed sexual maturation of young male rats, (2) delayed sexual maturation of young female rats, (3) inhibition of ovulation in mature female rats and (4) re-establishment of oestrous cycles in adult female rats maintained in continuous light. The inhibitory effect of daily melatonin injections, given in the afternoon, on the growth of the prostate gland and seminal vesicles and on serum testosterone concentrations in young male rats was prevented by daily injections of ML-23. Daily injections of ML-23 alone did not affect sexual maturation of young rats. In young male rats treated through the drinking water with melatonin, the growth of the accessory sex organs, but not that of the testes, was delayed and serum concentrations of testosterone were lower than in untreated rats. Administration of ML-23 through the drinking water increased serum concentrations of testosterone but did not significantly affect the weights of the accessory sex organs. Simultaneous administration of ML-23 and melatonin through the drinking water prevented completely, in a dose-dependent manner, the melatonin-mediated decrease in epididymal weights and in serum concentrations of testosterone and partially inhibited the delayed growth of the prostate glands and seminal vesicles. In young female rats treated with melatonin through the drinking water for 30 days, the growth of the ovaries was inhibited and serum concentrations of oestradiol were lower than in untreated rats. The growth of the uterus was not significantly affected. Administration of ML-23 through the drinking water did not significantly affect uterine and ovarian weights or oestradiol concentrations. Simultaneous administration of melatonin and ML-23 through the drinking water prevented completely the melatonin-mediated decrease in ovarian weights and in serum oestradiol concentrations. Ovulation during presumptive oestrus was prevented in adult female rats treated through the drinking water for 7 days with melatonin. Administration of ML-23 alone did not significantly affect the average numbers of ova shed and corpora lutea present. Simultaneous administration of ML-23 and melatonin prevented completely the melatonin-mediated inhibition of ovulation; the average number of ova shed was the same as in controls. Suppression of reproductive cycles occurred in adult female rats after long-term exposure to continuous light. This suppression was prevented by daily injections of melatonin in the afternoon; the incidence of constant oestrus decreased by 80%. Simultaneous injection of ML-23 and melatonin into rats maintained under continuous illumination prevented the effect of melatonin, and all the animals remained in constant oestrus. Administration of ML-23 alone did not alter the incidence of constant oestrus. A tritium-labelled derivative of ML-23 was prepared and administered orally to male rats. Peak concentrations of ML-23 occurred in the blood within 30 min after feeding and disappeared subsequently with a half-life of about 42 min. Intraperitoneal injection of [3H]ML-23 resulted in the appearance of peak concentrations of the drug in the brain within 20 min. The effects of ML-23 on serotonin S1 and S2 receptors, dopamine D2 receptors and melatonin receptors in the brain of the male rat were investigated using [3H]serotonin, [3H]spiperone and 2-[125I]iodomelatonin respectively. The binding of [3H]serotonin to brain synaptosomes and of [3H]spiperone to synaptosomes prepared from the cortical and caudate regions of the cerebrum was unaffected by ML-23 (10 μmol/l), whereas the binding of 2-[125I]iodomelatonin to brain synaptosomes was entirely inhibited. The results demonstrate the potency of ML-23 in antagonizing melatonin-mediated effects in the male and female rat in vivo. The drug may be administered to the animals simply through the drinking water, for relatively long periods without apparent deleterious effects on survival and welfare. ML-23 is accessible to both central and peripheral sites and acts specifically on melatonin but not on serotonin or dopamine receptors in the brain. The availability of a melatonin antagonist offers new opportunities for exploring the physiological role of melatonin in the neuroendocrine system. J. Endocr. (1988) 116, 43–53

scholarly journals The Influence of DMBA (7,12-dimethylbenz-[a]anthracene) Regimen In The Development of Mammae Carcinogénesis on Sprague Dawley Female Rat

2010 ◽  
Vol 1 (1) ◽  
pp. 60
Author(s):  
Agung Eru Wibowo ◽  
Sriningsih Sriningsih ◽  
Puspita Eka Wuyung ◽  
Raafqi Ranasasmita
Keyword(s):  
High Frequency ◽  
Histological Analysis ◽  
Ductal Carcinoma ◽  
Low Frequency ◽  
Female Rats ◽  
Female Rat ◽  
Sprague Dawley ◽  
Chemical Induction ◽  
Carcinogenic Agent ◽  
Hematoxylin Eosin

There are many methods for development of mammae cancer animal model, one of which is chemical induction using carcinogenic agent, DMBA. This research aimed to explore the influence of dose and time regimens of DMBA on development of mammae carcinogenesis on Sprague dawley female rats. The first study was 50 rats treated with 20 mg/kg bw of DMBA orally for eleven times at twice a week. Morphological evaluations were conducted with mammae palpation for 15 weeks and then all of rats were sacrificed for collecting mammae organs for histological analysis using hematoxylin-eosin staining. The results showed that the first and the latest nodules appeared at the fourth-week and the fourteenth-week after ending DMBA induction, respectively, in which the most often nodule appearances were at the seventh-week. The number of nodule incidence and multiplicity were by 74% and 2 noduls/rat, respectively. Histological analysis of mammae glands determined that they fell under in Ductal Carcinoma Invasive (DCIV) category. The second study was 25 rats gavaged orally with DMBA at dose 20 mg/kg bw for five times every three days. After palpating for 15 weeks, the results showed that no nodule was observed but the histological analysis demonstrated developing of mammae gland carcinogenesis reaching about 60% Ductal Carcinoma Insitu (DCIS) and 40% Ductal Carcinoma Invasive (DCIV) stages. Based on the results of this study can be concluded that the dose and frequency of DMBA will affect the successful development of mammary gland carcinogenesis. In DMBA induction with low frequency, no data showed the incidence and multiplicity of tumor, but histopathologic level carcinogenesis can be distinguished. In DMBA induction with high frequency, incidence and multiplicity of tumor data can be obtained but can not be distinguished histopathologically.Keywords: DMBA, doses, carcinogenesis, mammae, histopatology

Maternal aromatase inhibition via letrozole altered RFamide-related peptide-3 and gonadotropin releasing hormone expression in pubertal female rat

2021 ◽  
Author(s):  
Zahra Shaaban ◽  
Amin Tamadon ◽  
Mohammad Reza Jafarzadeh Shirazi ◽  
Mohammad Javad Zamiri ◽  
Amin Derakhshanfar
Keyword(s):  
Body Weight ◽  
Polycystic Ovary ◽  
Body Weight Gain ◽  
Late Pregnancy ◽  
Serum Testosterone ◽  
Female Offspring ◽  
Female Rats ◽  
Female Rat ◽  
Sprague Dawley ◽  
Letrozole Treatment

Abstract Despite the prevalence of polycystic ovary syndrome (PCOS) among childbearing women and the development of many animal models for this syndrome, information on its etiology is still scarce. Intrauterine hyperandrogenic environment may underlie changes at the levels of hypothalamus, pituitary and ovary organization in female offspring, and PCOS later in life. Letrozole, has been shown to mimic reproductive and metabolic characteristics of PCOS in adult rodent models. Therefore, the aim of this research was to assess the condition in a prenatal letrozole-treated rat model. Twenty-eight female rats from dams receiving letrozole at certain doses during late pregnancy were used in the trial. Pregnant Sprague-Dawley rats (n = 21) received letrozole treatment on days 16–18 gestation at doses 1.25, 1.0, 0.75, 0.5, and 0.25 mg/kg body weight (BW). Prenatal letrozole-treatment delayed parturition time and reduced the litter size in pregnant dams (P < 0.0001). Late puberty onset, irregular ovarian cyclicity, increased anogenital distance (AGD), body weight gain, and serum testosterone concentration and reduced estradiol levels (P < 0.0001) were observed in the female offspring of dams receiving 1.25 and 1 mg/kg BW letrozole. Furthermore, Letrozole at 1.25 and 1 mg/kg BW showed increased Rfrp and decreased Gnrh mRNA expression (P < 0.0001). Letrozole treatment at doses 1 mg/kg BW and lower was not feto-toxic. It was concluded that 1 mg/kg BW letrozole may be suggested for prenatal PCOS induction.

scholarly journals 17β-Estradiol Increases Astrocytic Vascular Endothelial Growth Factor (VEGF) in Adult Female Rat Hippocampus

Endocrinology ◽  
2011 ◽  
Vol 152 (5) ◽  
pp. 1745-1751 ◽  
Author(s):  
Sharon Barouk ◽  
Tana Hintz ◽  
Ping Li ◽  
Aine M. Duffy ◽  
Neil J. MacLusky ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Adult Female ◽  
Serum Levels ◽  
Female Rats ◽  
Female Rat ◽  
Vascular Endothelial ◽  
17Β Estradiol ◽  
Endothelial Growth Factor ◽  
Vegf Protein

Vascular endothelial growth factor (VEGF) is critical to angiogenesis and vascular permeability. It is also important in the endocrine system, in which VEGF mediates the vascular effects of estrogens in target tissues such as the uterus, a response attributed to an estrogen response element on the VEGF gene. Here we asked whether 17β-estradiol increases VEGF levels in the brain. We focused on the hippocampus, in which 17β-estradiol and VEGF both have important actions, and used immunocytochemistry to evaluate VEGF protein. VEGF immunoreactivity was compared in adult female rats sampled during the estrous cycle when serum levels of 17β-estradiol peak (proestrous morning) as well as when they are low (metestrous morning). In addition, adult rats were ovariectomized and compared after treatment with 17β-estradiol or vehicle. The results demonstrated that VEGF immunoreactivity was increased when serum levels of 17β-estradiol were elevated. Confocal microscopy showed that VEGF immunofluorescence was predominantly nonneuronal, often associated with astrocytes. Glial VEGF labeling was primarily punctate rather than diffuse and labile because glial VEGF immunoreactivity was greatly reduced if tissue sections were left in an aqueous medium overnight. We conclude that VEGF protein in normal female hippocampus is primarily nonneuronal rather than neuronal and suggest that glial VEGF immunoreactivity has been underestimated by past studies with other methods because there is a labile extracellular pool. We suggest that estrogens may exert actions on female hippocampal structure and function by increasing hippocampal VEGF.

Pituitary receptors for LH-releasing hormone (LHRH) and responsiveness to LHRH in adult female rats after neonatal monosodium l-glutamate treatment

1985 ◽  
Vol 107 (1) ◽  
pp. 9-13 ◽  
Author(s):  
S. E. Inkster ◽  
R. N. Clayton ◽  
S. A. Whitehead
Keyword(s):  
Adult Female ◽  
Female Rats ◽  
Serum Prolactin ◽  
Female Rat ◽  
Releasing Hormone ◽  
Old Rats ◽  
Lh Releasing Hormone ◽  
Ovarian Cyclicity ◽  
Pituitary Receptors

ABSTRACT The effects of neonatal monosodium l-glutamate (MSG) treatment on pituitary responsiveness to LH-releasing hormone (LHRH) and on pituitary LHRH receptors have been investigated in the intact adult female rat. Three- to four-month-old rats treated with MSG (4 mg/g body wt) on days 2, 4, 6, 8 and 10 after birth had significantly reduced ovarian and pituitary weights, showed an absence or disruption of ovarian cyclicity after puberty, and had significantly higher concentrations of serum prolactin despite normal levels of LH. In-vitro pituitary LH responses to LHRH were in the normal range for one group of treated animals whilst in a second group the LH responses were markedly enhanced. In contrast, the total number of pituitary LHRH receptors were significantly reduced in all MSG-treated animals showing that the increased pituitary responsiveness of MSG-treated animals is not attributable to an increase in pituitary LHRH receptors. J. Endocr. (1985) 107, 9–13

Effect of hypothyroidism on the pituitary-gonadal axis in the adult female rat

1995 ◽  
Vol 146 (1) ◽  
pp. 87-94 ◽  
Author(s):  
J A M Mattheij ◽  
J J M Swarts ◽  
P Lokerse ◽  
J T van Kampen ◽  
D Van der Heide
Keyword(s):  
Thyroid Hormone ◽  
Adult Female ◽  
Ovulation Rate ◽  
Female Rats ◽  
Corpora Lutea ◽  
Female Rat ◽  
Plasma Progesterone ◽  
Lh Surge ◽  
Before And After ◽  
Gonadotrophin Releasing Hormone

Abstract The pituitary-ovarian axis was studied after withdrawal of thyroid hormone in 131I-radiothyroidectomized adult female rats. Oestrous cycles became prolonged and irregular within 2 weeks after the supply of thyroid hormone was stopped. If an LH surge occurred in hypothyroid rats on the day of vaginal pro-oestrus it was significantly greater in rats which had been made hypothyroid for 4–5 weeks than in controls; in hypothyroid rats with an LH surge on pro-oestrus, plasma progesterone showed a rise similar to that in controls at pro-oestrus; the ovulation rate was decreased in hypothyroid rats. About half of the rats from which blood was sampled daily in the afternoon between 7 and 18 days after tri-iodothyronine (T3) withdrawal had 1 day of pro-oestrus; on this day the LH surge was higher than in controls. On days 2 and 1 before and days 1 and 2 after this pro-oestrus, plasma progesterone was similar to that of controls on days 2 and 1 before and days 1 and 2 after pro-oestrus respectively. However, progesterone was higher in the period before and after these days. The other hypothyroid rats showed no pro-oestrus and no LH surge during this period, while their plasma progesterone levels were high on all days. On the morning of day 10 after T3 withdrawal and 5 days after the preceding pro-oestrus, most hypothyroid rats had high progesterone and low oestradiol plasma levels. In these rats, injection of gonadotrophin-releasing hormone caused a relatively small increase in LH; it did not stimulate the secretion of oestradiol or progesterone, and it did not induce ovulation. It was concluded that hypothyroidism induces major changes in the secretion of steroids by corpora lutea and growing follicles. Whether the changed steroid metabolism is the primary cause of the observed prolongation of the oestrous cycles, the increased pro-oestrous LH surge and the reduced ovulation rate remains to be investigated. Journal of Endocrinology (1995) 146, 87–94

scholarly journals Functional and Muscle Size Response to 5 Days of Treadmill Training in Young Rats

1997 ◽  
Vol 9 (4) ◽  
pp. 324-330 ◽  
Author(s):  
Alon Eliakim ◽  
Mark Y. Moromisato ◽  
David Y. Moromisato ◽  
Dan M. Cooper
Keyword(s):  
Young Female ◽  
Treadmill Training ◽  
Female Rats ◽  
Muscle Size ◽  
Female Rat ◽  
Sprague Dawley ◽  
Running Time ◽  
Sprague Dawley Rats ◽  
Hindlimb Muscle ◽  
Training Response

In this study, the hypothesis that improvements in functional and structural measures could be detected in the young, female rat with only 5 days of moderate treadmill training was tested. Eight-week-old female Sprague-Dawley rats were divided randomly into control (n = 10) and training groups (n = 11). Over the 5-day period, running duration and treadmill speed increased progressively. Maximal running time and gas exchange were measured on Day 6. In trained compared with control rats, maximal running time was 54% greater (p < .005), right hindlimb muscle was 16% heavier (p < .01), and end-exercise respiratory exchange ratio (RER) was 17% lower (p < .05). Substantial metabolic and structural adaptations occurred in young female rats after only 5 days of treadmill training. This protocol may be useful in discovering the initiating mechanisms of the training response in the young organism.

scholarly journals Effect of colchicine on the uptake of prolactin and insulin into Golgi fractions of rat liver.

1982 ◽  
Vol 93 (3) ◽  
pp. 560-567 ◽  
Author(s):  
B I Posner ◽  
A K Verma ◽  
B A Patel ◽  
J J Bergeron
Keyword(s):  
Rat Liver ◽  
Adult Female ◽  
Colchicine Treatment ◽  
Inhibitory Effect ◽  
Female Rats ◽  
Female Rat ◽  
Uptake Process ◽  
Ovine Prolactin ◽  
And Control ◽  
Insulin Uptake

In previous studies we have shown that 125I-labeled prolactin is taken up by a receptor-dependent process and concentrated in an intact form in Golgi elements from female rat liver (J. Biol. Chem., 1979, 254:209-214). In this study we have examined the effect of colchicine on this uptake process into Golgi elements. Colchicine [25 mumol (10 mg)/100 gm body wt] was injected intraperitoneally in adult female rats, and hepatic Golgi fractions were prepared at 1, 2, and 3 h postinjection. The enzyme recoveries and morphological appearance of fractions from colchicine-treated and control (alcohol alone) animals were similar. At times greater than 1 h after colchicine there was a marked (greater than 60%) inhibition of uptake of 125I-ovine prolactin (125I-oPRL) into Golgi light and intermediate fractions but no inhibition of uptake into Golgi heavy and plasmalemma elements. At times from 2 to 45 min postinjection, 125I-oPRL was extracted from Golgi elements and found to be largely intact as judged by rebinding to receptors. The inhibitory effect of colchicine was seen at doses ranging from 0.25 mumol to 25 mumol/100 g body wt. Vincristine also inhibited 125I-oPRL uptake into the Golgi light and intermediate fractions but lumicolchicine had no inhibitory effect. There was a smaller effect of colchicine both at early (1 h) and later (3 h) times on the extent and pattern of 125I-insulin uptake. Colchicine treatment did not produce a significant change in lactogen receptor levels in the Golgi fractions. These results demonstrate that colchicine treatment inhibited the transfer of prolactin into Golgi vesicular elements. The much smaller effect on insulin uptake suggests that there may be differences in the manner in which the two hormones are handled in the course of internalization.

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