scholarly journals Two strategies used to solve a navigation task: A different use of the hippocampus by males and females? A preliminary study in rats

2018 ◽  
Vol 39 (2) ◽  
pp. 319-339 ◽  
Author(s):  
Ferran Lugo ◽  
Marta N. Torres ◽  
V.D. Chamizo
Keyword(s):  
Dorsal Hippocampus ◽  
Female Rats ◽  
Male Rats ◽  
Males And Females ◽  
Preliminary Study ◽  
Types Of Information ◽  
Landmark Learning ◽  
Source Of Information ◽  
Geometry Learning

AbstractThere is abundant research (both in rodents and in humans) showing that males and females often use different types of information in spatial navigation. Males prefer geometry as a source of information, whereas females tend to focus on landmarks (which are often near to a goal objects). However, when considering the role of the hippocampus, the research focuses primarily on males only. In the present study, based on Rodríguez, Torres, Mackintosh, and Chamizo’s (2010, Experiment 2) navigation protocol, we conducted two experiments, one with males and another with females, in order to tentatively evaluate the role of the dorsal hippocampus in the acquisition of two tasks: one based on landmark learning and the alternate one on local pool-geometry learning. Both when landmark learning and when geometry learning, Sham male rats learned significantly faster than Lesion male animals. This was not the case with female rats in geometry learning. These results suggest that the dorsal hippocampus could play an important role in males only.

scholarly journals Role of Age and Sex in Chronic Thyroiditis in Rats Fed 3'-Methyl-4-Dimethylaminoazobenzene

1976 ◽  
Vol 13 (4) ◽  
pp. 295-302 ◽  
Author(s):  
M. D. Reuber ◽  
E. L. Glover
Keyword(s):  
Female Rats ◽  
Male Rats ◽  
Deficient Diet ◽  
Chronic Thyroiditis ◽  
Male And Female ◽  
Low Protein ◽  
Males And Females ◽  
The Difference ◽  
Age And Sex

Inbred male and female Buffalo strain rats were started at 4, 8, 12, 24, or 52 weeks of age on 0.06% 3'-methyl-4-dimethylaminoazobenzene in a low-protein, choline-deficient diet. Eight-week-old males and females were the most susceptible to the development of chronic thyroiditis, but females were more susceptible than the males. Female rats of other ages developed a slightly higher incidence of thyroiditis than the male rats, the difference being most noticeable for rats 12 weeks old.

scholarly journals Role of Ventromedial Hypothalamus in Sucrose-Induced Obesity on Metabolic Parameters

2021 ◽  
pp. 097275312110057
Author(s):  
Archana Gaur ◽  
G.K. Pal ◽  
Pravati Pal
Keyword(s):  
Insulin Resistance ◽  
Weight Gain ◽  
Food Intake ◽  
Ventromedial Hypothalamus ◽  
Female Rats ◽  
Metabolic Parameters ◽  
Male Rats ◽  
Significant Weight Gain ◽  
The Metabolic Syndrome

Background: Obesity is because of excessive fat accumulation that affects health adversely in the form of various diseases such as diabetes, hypertension, cardiovascular diseases, and many other disorders. Our Indian diet is rich in carbohydrates, and hence the sucrose-induced obesity is an apt model to mimic this. Ventromedial hypothalamus (VMH) is linked to the regulation of food intake in animals as well as humans. Purpose: To understand the role of VMHin sucrose-induced obesity on metabolic parameters. Methods: A total of 24 adult rats were made obese by feeding them on a 32% sucrose solution for 10 weeks. The VMH nucleus was ablated in the experimental group and sham lesions were made in the control group. Food intake, body weight, and biochemical parameters were compared before and after the lesion. Results: Male rats had a significant weight gain along with hyperphagia, whereas female rats did not have a significant weight gain inspite of hyperphagia. Insulin resistance and dyslipidemia were seen in both the experimental and control groups. Conclusion: A sucrose diet produces obesity which is similar to the metabolic syndrome with insulin resistance and dyslipidemia, and a VMH lesion further exaggerates it. Males are more prone to this exaggeration.

scholarly journals Risk-based Decision Making in Rats: Modulation by Sex and Amphetamine

2020 ◽  
Author(s):  
Dannia Islas-Preciado ◽  
Steven R. Wainwright ◽  
Julia Sniegocki ◽  
Stephane E. Lieblich ◽  
Shunya Yagi ◽  
...  
Keyword(s):  
Decision Making ◽  
Sex Differences ◽  
Gonadal Hormones ◽  
Risky Choice ◽  
Female Rats ◽  
Male Rats ◽  
Risky Decision Making ◽  
Risky Decision ◽  
17Β Estradiol ◽  
Males And Females

AbstractDecision-making is a complex process essential to daily adaptation in many species. Risk is an inherent aspect of decision-making and it is influenced by gonadal hormones. Testosterone and 17β-estradiol may modulate decision making and impact the mesocorticolimbic dopamine pathway. Here, we explored sex differences, the effect of gonadal hormones and the dopamine agonist amphetamine on risk-based decision making. Intact or gonadectomised (GDX) male and female rats underwent to a probabilistic discounting task. High and low doses of testosterone propionate (1.0 or 0.2 mg) and 17β-estradiol benzoate (0.3 μg) were administered to assess acute effects on risk-based decision making. After 3-days of washout period, intact and GDX rats received high or low (0.5 or 0.125 mg/kg) doses of amphetamine and re-tested in the probabilistic discounting task. Under baseline conditions, males made more risky choices during probability discounting compared to female rats, particularly in the lower probability blocks, but GDX did not influence risky choice. The high, but not the low dose, of testosterone modestly reduced risky decision making in GDX male rats. Conversely, 17β-estradiol had no significant effect on risky choice regardless of GDX status in either sex. Lastly, a higher dose of amphetamine increased risky decision making in both intact males and females, but had no effect in GDX rats. These findings demonstrated sex differences in risk-based decision making, with males showing a stronger bias towards larger, uncertain rewards. GDX status influenced the effects of amphetamine, suggesting different dopaminergic regulation in risk-based choices among males and females.

Cimetidine-induced prolactin release in rats The effect of sex and gonadal steroids

1987 ◽  
Vol 114 (2) ◽  
pp. 178-184 ◽  
Author(s):  
Hajime Watanobe ◽  
Kazuo Takebe
Keyword(s):  
Anterior Pituitary ◽  
Male Rats ◽  
Minor Role ◽  
Adult Males ◽  
Adult Age ◽  
Significant Difference ◽  
Males And Females ◽  
Plasma Prl ◽  
A Minor

Abstract. The cimetidine-induced plasma Prl response was examined in rats of both sexes. First, 10 week old intact adult males and females (dioestrous) were compared. There was no significant difference in the Prl response to cimetidine between the two groups, despite the fact that in adult females the anterior pituitary Prl content was 4 times greater than in males. Second, the effect of gonadal state in adult age on the Prl response to cimetidine was examined in both sexes. In male rats, gonadectomy at the age of 6 weeks significantly reduced the plasma Prl response as well as the pituitary Prl content, both of which were sufficiently restored by testosterone replacement. However, in females, neither gonadectomy at the age of 6 weeks nor subsequent oestradiol replacement affected the Prl response to cimetidine, despite the fact that gonadectomy significantly reduced and oestradiol treatment significantly enhanced the pituitary Prl content. Third, possible permanent effects of the postnatal gonadal milieu on the cimetidine-induced Prl response and the pituitary Prl content were examined in both sexes by castration at varying postnatal ages. The ratio of plasma Prl response to pituitary Prl content was similar in all castrated males. In females, however, the ratio decreased with increasing castration age. In conclusion, the mechanism of cimetidine-induced Prl release is less sex-dependent than are the mechanisms of Prl release by other Prl secretagogues. First, this may be due to a minor role of oestrogen in females in determining the Prl response to cimetidine. Second, the postnatal ovarian secretions may exert a permanent inhibition of the development of the cimetidine-mobilized anterior pituitary Prl pool.

scholarly journals Sex Differences in Demand for Highly Palatable Foods: Role of the Orexin System

2020 ◽  
Author(s):  
Linnea R Freeman ◽  
Brandon S Bentzley ◽  
Morgan H James ◽  
Gary Aston-Jones
Keyword(s):  
Sex Differences ◽  
Demand Curve ◽  
Female Rats ◽  
Demand Elasticity ◽  
Male Rats ◽  
Neural Activation ◽  
Palatable Food ◽  
Behavioral Economic ◽  
Male And Female Rats

Abstract Background The prevalence of eating disorders, including binge eating disorder, is significantly higher in women. These findings are mirrored by preclinical studies, which indicate that female rats have a higher preference for palatable food and show greater binge-like eating compared with male rats. Methods Here, we describe a novel within-session behavioral-economic paradigm that allows for the simultaneous measurement of the intake at null cost (Q0) and normalized demand elasticity (α) of 3 types of palatable food (low fat, high fat, and chocolate sucrose pellets) via demand curve analysis. In light of evidence that the orexin (hypocretin) system is critically involved in reward and feeding behaviors, we also examined the role of orexin function in sex differences of economic demand for palatable foods. Results The novel within-session behavioral-economic approach revealed that female rats have higher intake (demand) than males for all palatable foods at low cost (normalized to body weight) but no difference in intake at higher prices, indicating sex-dependent differences in the hedonic, but not motivational, aspects of palatable food. Immediately following behavioral-economic testing, we observed more orexin-expressing neurons and Fos expression (measure of recent neural activation) in these neurons in female rats compared with male rats. Moreover, the orexin-1 receptor antagonist SB334867 reduced both low- and high-cost intake for palatable food in both male and female rats. Conclusions These findings provide evidence of higher demand at low prices for palatable food in females and indicate that these behavioral differences may be associated with sexual dimorphism in orexin system function.

scholarly journals Is Hippocampus Susceptible to Antinociceptive Tolerance to NSAIDs Like the Periaqueductal Grey?

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Nana Tsiklauri ◽  
Ivliane Nozadze ◽  
Gulnazi Gurtskaia ◽  
Merab G. Tsagareli
Keyword(s):  
Dorsal Hippocampus ◽  
Antinociceptive Effect ◽  
Male Rats ◽  
Opioid Antagonist ◽  
Tail Flick ◽  
Pain Models ◽  
Inflammatory Drugs ◽  
Antinociceptive Tolerance ◽  
Undesirable Feature

Emotional distress is the most undesirable feature of painful experience. Numerous studies have demonstrated the important role of the limbic system in the affective-motivational component of pain. The purpose of this paper was to examine whether microinjection of nonsteroidal anti-inflammatory drugs (NSAIDs), Clodifen, Ketorolac, and Xefocam, into the dorsal hippocampus (DH) leads to the development of antinociceptive tolerance in male rats. We found that microinjection of these NSAIDs into the DH induces antinociception as revealed by a latency increase in the tail-flick (TF) and hot plate (HP) tests compared to controls treated with saline into the DH. Subsequent tests on consecutive three days, however, showed that the antinociceptive effect of NSAIDs progressively decreased, suggesting tolerance developed to this effect of NSAIDs. Both pretreatment and posttreatment with the opioid antagonist naloxone into the DH significantly reduced the antinociceptive effect of NSAIDs in both pain models. Our data indicate that microinjection of NSAIDs into the DH induces antinociception which is mediated via the opioid system and exhibits tolerance.

scholarly journals Male gender increases sensitivity to proteinuria induced by mild NOS inhibition in rats: role of sex hormones

2000 ◽  
Vol 279 (4) ◽  
pp. F664-F670 ◽  
Author(s):  
A. Marjan G. Verhagen ◽  
Diana M. A. Attia ◽  
Hein A. Koomans ◽  
Jaap A. Joles
Keyword(s):  
Nitric Oxide ◽  
Sex Hormones ◽  
Oxide System ◽  
Female Rats ◽  
Male Rats ◽  
Time Control ◽  
Ovx Rats ◽  
Increased Sensitivity ◽  
Dose Dependent Increase

Men are at greater risk for renal injury than women. We studied whether male rats are more sensitive to the hypertensive and proteinuric effects of chronic nitric oxide sythase (NOS) inhibition than female rats. In addition, we studied whether androgens or estrogens are responsible for differences in sensitivity to proteinuria induced by chronic NOS inhibition. Females and males were treated with 10, 20, 30, and 100 mg/l N ω-nitro-l-arginine (l-NNA) during 24 wk. Systolic blood pressure (SBP) and proteinuria were measured regularly and compared with time-control measurements in control females and males. In females and males treatment with 10 mg/l l-NNA had no effect on SBP or proteinuria. Treatment with 20, 30, and 100 mg/l l-NNA resulted in a dose-dependent increase in SBP that was similar in males and females. However, females treated with 20 and 30 mg/ll-NNA were resistant to the development of proteinuria: maximum values were 16 ± 7 and 46 ± 21, respectively, vs. 16 ± 3 mg/day in controls, whereas males treated with those doses showed an increase in proteinuria [139 ± 35 ( P< 0.05) and 318 ± 82 ( P < 0.01), respectively, vs. 55 ± 11 mg/day in controls]. Treatment with 100 mg/ll-NNA increased proteinuria similarly in both females and males. To study the role of sex hormones in differences in sensitivity to proteinuria induced by mild chronic NOS inhibition, treatment with 20 mg/l l-NNA was repeated in ovariectomized (Ovx) and orchidectomized rats. Ovariectomy did not affect the increase in SBP caused by 20 mg/l l-NNA, but, in contrast to intact females, this dose of l-NNA did cause Ovx rats to develop proteinuria (51 ± 16 vs. 16 ± 7 mg/day in control Ovx rats; P < 0.05). Orchidectomy completely prevented the increased SBP as well as proteinuria induced by 20 mg/ll-NNA in male rats. In conclusion, male rats are more sensitive than female rats to develop proteinuria induced by mild chronic NOS inhibition. Estrogens provide some protection in females, whereas androgens are responsible for the increased sensitivity of male rats to proteinuria induced by mild chronic NOS inhibition. Risk factors associated with a compromised nitric oxide system may be more detrimental to the kidney in men than in women.

Indicators of oxidative stress in weanling and pubertal rats following exposure to nicotine via milk

2009 ◽  
Vol 29 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Ben Ahmed Halima ◽  
Khlifi Sarra ◽  
Rtibi Kais ◽  
Elfazaa Salwa ◽  
Gharbi Najoua
Keyword(s):  
Oxidative Stress ◽  
Wistar Rats ◽  
Female Rats ◽  
Male Rats ◽  
Nicotine Exposure ◽  
Lactation Period ◽  
Aspartate Amino Transferase ◽  
Males And Females ◽  
Breast Fed ◽  
Biomarkers Of Oxidative Stress

Nicotine, a major toxic component of tobacco, has been identified as an important risk factor for infant and children diseases. It is concentrated in breast milk and is absorbed by the infant. The purpose of the present study was to investigate the effects of maternal nicotine exposure during lactation on breast-fed rats and at the pubertal age by measuring biomarkers of oxidative stress. Particularly, a new parameter, the thiol concentration was evaluated. Two groups of lactating Wistar rats were used. For the first group, female rats were given an intraperitoenal injection of nicotine or saline (2 mg/kg per day) during lactation. For the second group, we reproduced the same process described above and then the female and male pups were separately kept after weaning without any treatment until the puberty (at 45 days of age). In the liver and lung of the offspring, we examined the malondialdehyde (MDA) level, the thiol concentration, and the activities of two antioxidant enzymes: superoxyde dismutase (SOD) and catalase (CAT). In the plasma, alanine amino transferase (ALT) and aspartate amino transferase (AST) activities were measured. For rats aged 21 days, the treatment significantly reduced the thiol concentration, SOD, and CAT activities but increased MDA level, AST, and ALT activities. For rats aged 45 days, the males and females did not react the same way. In fact, the males were more affected. These results indicate that maternal nicotine exposure during the lactation period induces oxidative stress in the liver and lung of lactating offspring, which is maintained until the puberty, especially for the male rats.

scholarly journals GPER modulates tone and coronary vascular reactivity in male and female rats

2017 ◽  
Vol 59 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Angelina Rafaela Debortoli ◽  
Wender do Nascimento Rouver ◽  
Nathalie Tristão Banhos Delgado ◽  
Vinicius Mengal ◽  
Erick Roberto Gonçalves Claudio ◽  
...  
Keyword(s):  
Protein Expression ◽  
Vascular Reactivity ◽  
Coronary Circulation ◽  
Superoxide Production ◽  
Female Rats ◽  
Male Rats ◽  
Coronary Perfusion ◽  
Dependent Manner ◽  
Coronary Tone

Compared with age-matched men, premenopausal women are largely protected from coronary artery disease, a difference that is lost after menopause. The effects of oestrogens are mediated by the activation of nuclear receptors (ERα and ERβ) and by the G protein-coupled oestrogen receptor (GPER). This study aims to evaluate the potential role of GPER in coronary circulation in female and male rats. The baseline coronary perfusion pressure (CPP) and the concentration–response curve with a GPER agonist (G-1) were evaluated in isolated hearts before and after the blockade of GPER. GPER, superoxide dismutase (SOD-2), catalase and gp91phox protein expression were assessed by Western blotting. Superoxide production was evaluated ‘in situ’ via dihydroethidium fluorescence (DHE). GPER blockade significantly increased the CPP in both groups, demonstrating the modulation of coronary tone by GPER. G-1 causes relaxation of the coronary bed in a concentration-dependent manner and was significantly higher in female rats. No differences were detected in GPER, SOD-2 and catalase protein expression. However, gp91phox expression and DHE fluorescence were higher in male rats, indicating elevated superoxide production. Therefore, GPER plays an important role in modulating coronary tone and reactivity in female and male rats. The observed differences in vascular reactivity may be related to the higher superoxide production in male rats. These findings help to elucidate the role of GPER-modulating coronary circulation, providing new information to develop a potential therapeutic target for the treatment of coronary heart disease.

scholarly journals Local Cerebral Glucose Utilization in Normal Female Rats: Variations during the Estrous Cycle and Comparison with Males

1985 ◽  
Vol 5 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Astrid Nehlig ◽  
Linda J. Porrino ◽  
Alison M. Crane ◽  
Louis Sokoloff
Keyword(s):  
Estrous Cycle ◽  
Glucose Utilization ◽  
Brain Regions ◽  
Female Rats ◽  
Male Rats ◽  
Normal Male ◽  
Normal Female ◽  
Female Rat ◽  
Males And Females ◽  
The Brain

The quantitative 2-[14C]deoxyglucose autoradiographic method was used to study the fluctuations of energy metabolism in discrete brain regions of female rats during the estrous cycle. A consistent though statistically nonsignificant cyclic variation in average glucose utilization of the brain as a whole was observed. Highest levels of glucose utilization occurred during proestrus and metestrus, whereas lower rates were found during estrus and diestrus. Statistically significant fluctuations were found specifically in the hypothalamus and in some limbic structures. Rates of glucose utilization in the female rat brain were compared with rates in normal male rats. Statistically significant differences between males and females at any stage of the estrous cycle were confined mainly to hypothalamic areas known to be involved in the control of sexual behavior. Glucose utilization in males and females was not significantly different in most other cerebral structures.

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