Effects of estrogen on thermoregulatory tail vasomotion and heat-escape behavior in freely moving female rats

2001 ◽  
Vol 280 (5) ◽  
pp. R1341-R1347 ◽  
Author(s):  
Takayoshi Hosono ◽  
Xiao-Ming Chen ◽  
Aya Miyatsuji ◽  
Tamae Yoda ◽  
Kyoko Yoshida ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Escape Behavior ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Thermoregulatory Behavior ◽  
Ambient Temperatures ◽  
Significant Difference ◽  
Vasomotor Activity ◽  
Freely Moving ◽  
Escape Behaviors

Effects of estrogen on thermoregulatory vasomotion and heat-escape behavior were investigated in ovariectomized female rats supplemented with estrogen (replaced estrogen rats) or control saline (low estrogen rats). First, we measured tail temperature of freely moving rats at ambient temperatures (Ta) between 13 and 31°C. Tail temperature of the low estrogen rats was higher than that of the replaced estrogen rats at Ta between 19 and 25°C, indicating that the low estrogen rats exhibit more skin vasodilation than the replaced estrogen rats. There was no significant difference in oxygen consumption and core temperature between the two groups. Second, we analyzed heat-escape behaviors in a hot chamber where rats could obtain cold air by moving in and out of a reward area. The low estrogen rats kept Ta at a lower level than did the replaced estrogen rats. These results imply that the lack of estrogen facilitates heat dissipation both by skin vasodilation and by heat-escape behavior. Ovariectomized rats may mimic climacteric hot flushes not only for autonomic skin vasomotor activity but also for thermoregulatory behavior.

scholarly journals The Effect of Tomato Juice in Increasing Ki-67 Expression and Epithelial Thickness on The Vaginal Wall of Menopausal Rats

2019 ◽  
Vol 11 (2) ◽  
pp. 152-8
Author(s):  
Juminten Saimin ◽  
Hendy Hendarto ◽  
Soetjipto Soetjipto
Keyword(s):  
Cell Proliferation ◽  
Vaginal Wall ◽  
Tomato Juice ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Distilled Water ◽  
Ki 67 ◽  
Treatment Groups ◽  
Epithelial Thickness ◽  
Significant Difference

BACKGROUND: Dyspareunia and pain due to the decrease of vaginal wall thickness usually happen in menopausal women. The reduction of estrogen levels cause the decreasing of cell proliferation and the thinning of vaginal wall epithelium. Tomato (Solanum lycopersicum) is a source of phytoestrogens, which produce estrogenic effects. This study aims to assess the effect of tomato juice on Ki-67 expression and epithelial thickness of the vaginal wall in menopausal rats.METHODS: This was an experimental study using Sprague-Dawley rats. Twenty-four female rats, aged 4 months and weighing 150-200 grams, were divided into 4 groups. Each group consisted of 6 rats. Negative control (NC) group was group of rats with sham procedure and performed by distilled water for 28 days. Positive control (PC) group was group of bilateral ovariectomized rats and performed by distilled water for 28 days. The first treatment (T1) group was group of bilateral ovariectomized rats, given tomato juice at dose of 11g/200g body weight (BW)/day. The second treatment (T2) group was group of bilateral ovariectomized rats, given tomato juice at dose of 15g/200g BW/day. Data analysis was done with Anova, multiple comparisons and regression test.RESULTS: The group with lowest Ki-67 expression was PC group (2.52±0.60). The expression of Ki-67 in treatment groups (T1 and T2) was higher than PC group, but lower than NC group. There was no significant difference between groups (p=0.771). The lowest epithelial thickness was found in PC group (21.19±3.96) and the highest was found in the treatment groups (38.73±12.43). There was positive correlation between tomato juice and epithelial thickness (p=0.647).CONCLUSION: Tomato juice increases Ki-67 expression and epithelial thickness on the vaginal wall of menopausal rats. The increase of epithelial thickness follows the administration dose, but Ki-67 expression does not exceed in the control rats. Tomato juice increases the cell proliferation of vaginal wall on menopausal rats, however the increase is still within normal limits.KEYWORDS: epithelial thickness, Ki-67, menopause, tomato juice

scholarly journals Neurokinin 3 Receptor-Expressing Neurons in the Median Preoptic Nucleus Modulate Heat-Dissipation Effectors in the Female Rat

Endocrinology ◽  
2015 ◽  
Vol 156 (7) ◽  
pp. 2552-2562 ◽  
Author(s):  
Melinda A. Mittelman-Smith ◽  
Sally J. Krajewski-Hall ◽  
Nathaniel T. McMullen ◽  
Naomi E. Rance
Keyword(s):  
Heat Dissipation ◽  
Medial Septum ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Preoptic Nucleus ◽  
Ambient Temperatures ◽  
Median Preoptic Nucleus ◽  
Cutaneous Vasodilation ◽  
Neurokinin 3 Receptor ◽  
Kndy Neurons

KNDy neurons facilitate tail skin vasodilation and modulate the effects of estradiol on thermoregulation. We hypothesize that KNDy neurons influence cutaneous vasodilation via projections to neurons in the median preoptic nucleus (MnPO) that express the neurokinin 3 receptor (NK3R). In support of this hypothesis, focal microinjections of senktide, an NK3R agonist, into the MnPO lowers core temperature (TCORE) in the female rat. To further study the role of MnPO NK3R neurons in thermoregulation, these neurons were specifically ablated using a conjugate of a selective NK3R agonist and saporin (NK3-SAP). NK3-SAP or blank-SAP (control) was injected into the MnPO/medial septum. Tail skin temperature (TSKIN) and TCORE were measured in ovariectomized rats exposed to 3 ambient temperatures (TAMBIENT) before and after estradiol-17β (E2) treatment. Before killing, we injected senktide (sc), monitored TCORE for 70 minutes, and harvested brains for Fos immunohistochemistry. Ablation of MnPO NK3R neurons lowered TSKIN at neutral and subneutral TAMBIENT regardless of E2 treatment. However, ablation did not prevent the effects of E2 on TCORE and TSKIN. In control rats, senktide injections induced hypothermia with numerous Fos-immunoreactive cells in the MnPO. In contrast, in NK3-SAP rats, senktide did not alter TCORE and minimal Fos-immunoreactive neurons were identified in the MnPO. These data show that NK3R neurons in the MnPO are required for the hypothermic effects of senktide but not for the E2 modulation of thermoregulation. The lower TSKIN in NK3-SAP–injected rats suggests that MnPO NK3R neurons, like KNDy neurons, facilitate cutaneous vasodilation, an important heat-dissipation effector.

scholarly journals Depressive Behavior of Rats Consuming Cocoa Powder and Cocoa Extract

2018 ◽  
Vol 34 (2) ◽  
pp. 90-94
Author(s):  
Ariza Budi Tunjung Sari ◽  
Misnawi Misnawi ◽  
Pratiwi Pudjiastuti ◽  
Afaf Baktir
Keyword(s):  
Treatment Time ◽  
Estrogenic Activity ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Vehicle Group ◽  
Estradiol Valerate ◽  
Depressive Behavior ◽  
Cocoa Powder ◽  
Immobility Time ◽  
Significant Difference

Chocolate is associated with calm and happy feelings. However little is found to demonstrate if this effect is induced by active ingredient in cocoa ratherthan the sweetness of chocolate. In this study we tested the effect of cocoa on the depressive behavior of female rats suffering from estrogen deficiency. Twentyfemale rats aged seven weeks old were ovariectomized to remove the estrogen source. The rats were distributed into four groups and undergoing three dayoral administration of 1g/kg body weight (bw) cocoa powder, 1g/kg bw cocoa extract, 1 mg/kg bw estradiol valerate and 1 mL/kg bw vehicle (olive oil). Anothergroup of rats having intact ovaries received 1 mL/kg bw drinking water. The rats were undergoing forced swimming test (FST) one day before treatment and after treatment and the immobility time was recorded. No significant difference was found on the after-treatment immobility time across groups. However, all the rats in the vehicle group developed longer immobility time after-treatment compared with the result from before-treatment test, suggesting that depression had occurred in ovariectomized rats receiving no active substances. In the other hand, very few rats had greater after-treatment immobility time in the cocoa powder and estradiol valerate groups. In the cocoa extract group, all the rats had shorter immobility time after treatment when it is compared with before treatment time. We conclude that compounds in cocoa have certain extent of estrogenic activity that affects emotional state.

scholarly journals Involvement of Brainstem Catecholaminergic Inputs to the Hypothalamic Paraventricular Nucleus in Estrogen Receptor α Expression in this Nucleus during Different Stress Conditions in Female Rats

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 4917-4926 ◽  
Author(s):  
Maria Amelita C. Estacio ◽  
Hiroko Tsukamura ◽  
Beverly A. S. Reyes ◽  
Yoshihisa Uenoyama ◽  
Helen I’Anson ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Paraventricular Nucleus ◽  
Estrogen Receptor Α ◽  
Stress Conditions ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Cell Group ◽  
Slight Reduction ◽  
Significant Difference ◽  
Cell Groups

Abstract In the present study, we determined the involvement of brainstem catecholaminergic inputs to the paraventricular nucleus (PVN) on estrogen receptor α (ERα) expression in this nucleus during conditions of 48-h fasting, 2-deoxy-d-glucose (2DG)-induced acute glucoprivation and 1-h immobilization, in ovariectomized rats. Our approach was to examine the effect of lesioning catecholaminergic inputs to the PVN using DSAP [saporin-conjugated anti-DBH (dopamine-β-hydroxylase)]. Bilateral injection of DSAP into the PVN, 2 wk before stress, prevented fasting-, glucoprivation-, and immobilization-induced increase in ERα-immunopositive cells in the PVN. The DBH-immunoreactive (ir) terminals in the PVN were severely depleted by DSAP injection in all experimental groups. Among the brainstem noradreneregic cell groups examined, DBH-ir cell bodies were significantly reduced in the A2 region of all experimental groups treated with DSAP compared with the saporin- and vehicle-injected controls. PVN DSAP injection caused a small, but not significant, decrease in A1 DBH-ir cell bodies in fasted and immobilized rats, and a significant, but slight, reduction in A1 DBH-ir cell bodies of iv 2DG- injected rats compared with PVN vehicle-injected or PVN saporin-injected controls. The A6 DBH-ir cell bodies in all experimental groups treated with DSAP, saporin, or vehicle did not show any significant difference. These results suggest that the brainstem catecholaminergic inputs to the PVN, especially from the A2 cell group, may play a major role in mediating the induction of ERα expression in the PVN by metabolic stressors such as fasting, acute glucoprivation, and less specific stressors, such as immobilization, in female rats.

scholarly journals Heat dissipation in subterranean rodents: the role of body region and social organisation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
František Vejmělka ◽  
Jan Okrouhlík ◽  
Matěj Lövy ◽  
Gabriel Šaffa ◽  
Eviatar Nevo ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Heat Dissipation ◽  
Ventral Surface ◽  
Body Region ◽  
Subterranean Rodents ◽  
Ambient Temperatures ◽  
Social Species ◽  
Body Regions ◽  
Body Heat ◽  
Solitary Species

AbstractThe relatively warm and very humid environment of burrows presents a challenge for thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate body heat mainly through their venter, and social mole-rats dissipate more body heat compared to solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface temperatures of seven species with different degrees of sociality, phylogeny, and climate using infrared thermography. In all species, heat dissipation occurred mainly through the venter and the feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures indicating that heat dissipation to the environment through this body region is regulated mainly by behavioural means. Solitary species dissipated less heat through their dorsum than social species, and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface temperature through the venter was not related to sociality of the various species. Our results demonstrate a general pattern of body heat exchange through the three studied body regions in subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves against low ambient temperatures, which may handicap them if staying alone for a longer period, such as during and after dispersal events.

scholarly journals Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Convective Heat ◽  
Heat Dissipation ◽  
High Surface ◽  
Heat Sinks ◽  
Fourth Power ◽  
Molding Process ◽  
Ambient Temperatures ◽  
University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

The effect of table olive wastewater extract administration on the adult ovariectomized rat model of osteoporosis

2021 ◽  
pp. 1-26
Author(s):  
Alexandros S. Zervas ◽  
Pavlos P. Lelovas ◽  
Antonios Galanos ◽  
Dimitris Galanis ◽  
Maria Makropoulou ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Biomechanical Testing ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Abdominal Fat ◽  
Ovariectomized Rats ◽  
Mineral Density ◽  
Final Body Weight ◽  
Significant Difference ◽  
Table Olive

Abstract Recent efforts for alternative non-pharmaceutical treatments for postmenopausal osteoporosis are focused on nutritional measures. The aim of this study was to investigate the effect of table olive wastewater extract (OE) administration on bone mineral density (BMD) and biomechanical strength in ovariectomized rats. Thirty mature 9-month-old female Wistar rats were separated into 3 groups of ten; Control, Ovariectomized (OVX) and OVX+OE. BMD was measured before ovariectomy, 3 and 6 months afterwards. At the end of the study, blood, both femurs and tibias, internal organs and abdominal fat were collected. After three months, the percentage changes from baseline of the total and proximal tibial BMD of the OVX+OE group were both higher compared to the OVX group (p<0.005). Similar results were found after six months, when the percentage changes from baseline of the total and proximal tibial BMD of the OVX+OE group were both higher compared to the OVX group (p<0.005). Biomechanical testing of the femurs did not reveal any statistically significant difference between the groups. Body weights throughout the study, organs’ and abdominal fat ratios to final body weight, blood results (alanine aminotransferase; ALT, Gamma-glutamyltransferase; γ-GT, total cholesterol, high-density lipoprotein; HDL-cholesterol, low-density lipoprotein; LDL-cholesterol, calcium, phosphorus) were within normal limits and did not show any significant difference between the treated and untreated groups. As a conclusion, the administration of table olive wastewater extract for 6 months protected tibial BMD loss in comparison to the untreated OVX group without causing adverse effects.

Changes in the characteristics of pulsatile luteinizing hormone secretion during the oestrous cycle and after ovariectomy and oestrogen treatment in female rats

1982 ◽  
Vol 94 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Takashi Higuchi ◽  
Masazumi Kawakami
Keyword(s):  
Hormone Secretion ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Luteinizing Hormone Secretion ◽  
Oestrogen Treatment ◽  
Serum Lh ◽  
Lh Release

Changes in the characteristics of LH secretory pulses in female rats were determined in different hormonal conditions; during the oestrous cycle and after ovariectomy and oestrogen treatment. The frequency and amplitude of the LH pulses were stable during the oestrous cycle except at oestrus when a pattern could not be discerned because of low LH concentrations. These were significantly lower than those measured during other stages of the cycle. Mean LH concentrations and LH pulse amplitudes increased with time up to 30 days after ovariectomy. The frequency of the LH pulse was unchanged 4 days after ovariectomy when mean LH levels had already increased. The frequency increased 10 days after ovariectomy and then remained stable in spite of a further increase in mean serum LH concentrations. Oestradiol-17β injected into ovariectomized rats caused a decrease in LH pulse amplitude but no change in pulse frequency. One day after treatment with oestradiol benzoate no LH pulse was detectable, probably because the amplitude was too small. A generator of pulsatile LH release is postulated and an oestrogen effect on its function is discussed.

Indomethacin treatment prevents prolactin-induced luteolysis in the rat

1987 ◽  
Vol 112 (2) ◽  
pp. 317-322 ◽  
Author(s):  
J. E. Sánchez-Criado ◽  
K. Ochiai ◽  
I. Rothchild
Keyword(s):  
Corpus Luteum ◽  
Left Kidney ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Silicone Elastomer ◽  
Serum Prolactin ◽  
Corpora Lutea ◽  
Synthesis Inhibitor ◽  
Significant Difference ◽  
Indomethacin Treatment

ABSTRACT Adult female rats were hypophysectomized and their pituitary glands autotransplanted beneath the left kidney capsule on day 2 (day 1 was the day of ovulation). In such rats the pituitary secretes prolactin fairly constantly and the corpora lutea secrete progesterone for several months. To induce the luteolytic effect of prolactin the rats were first injected s.c. with 2-bromo-α-ergocryptine (CB-154) on cycle days 12, 13 and 14 (i.e. 10, 11 and 12 days after operation) to depress prolactin secretion, and then with CB-154 vehicle (70% ethanol) daily until cycle day 21, to allow prolactin secretion to resume. One ovary was removed from each rat on day 15 and the remaining one on day 22. The mean (± s.e.m.) weight of the corpora lutea on day 15 was 1·46±0·06 mg and 0·98±0·07 mg on day 22 (n = 17). In contrast, rats in which the CB-154 treatment was maintained to day 21 had corpora lutea which weighed 1·31 ±0·09 on day 15 and 1·47 ±0·08 mg on day 22 (n = 15). To investigate whether indomethacin, a prostaglandin synthesis inhibitor, affected the luteolytic action of prolactin, the experiment was repeated, but on day 15 (after the removal of one ovary) the groups in which CB-154 treatment was stopped, as well as the group in which CB-154 treatment was maintained, were each divided into two groups. In one, indomethacin-containing silicone elastomer wafers and, in the other, blank silicone elastomer wafers, were placed within the bursa of the remaining ovary. There were no differences in corpus luteum weight on day 15 among any of these groups and the two groups of the first experiment. There was no significant difference in corpus luteum weight between day 15 and day 22 in any of the six groups except for the two groups treated with the CB-154 vehicle and not with indomethacin. Thus, treatment with indomethacin prevented the fall in corpus luteum weight associated with the discontinuation of CB-154 treatment. Serum prolactin levels fell until day 15 in all rats and remained low in those in which the CB-154 treatment was maintained to day 21, but returned to control values in those treated with vehicle after day 14. Serum progesterone levels fell and remained low in all groups. Indomethacin treatment had no effect on the levels of either serum prolactin or progesterone. We conclude that some of the pharmacological effects of indomethacin are to prevent prolactin-induced luteolysis, and we suggest that prolactin induces rapid regression of the corpus luteum by stimulating intraluteal prostaglandin production or by being necessary for the effect of luteolytic prostaglandins. J. Endocr. (1987) 112, 317–322

scholarly journals The Increase in Signaling by Kisspeptin Neurons in the Preoptic Area and Associated Changes in Clock Gene Expression That Trigger the LH Surge in Female Rats Are Dependent on the Facilitatory Action of a Noradrenaline Input

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 323-335 ◽  
Author(s):  
Bruna Kalil ◽  
Aline B. Ribeiro ◽  
Cristiane M. Leite ◽  
Ernane T. Uchôa ◽  
Ruither O. Carolino ◽  
...  
Keyword(s):  
Gene Expression ◽  
Median Eminence ◽  
Preoptic Area ◽  
Clock Genes ◽  
Third Ventricle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Lh Surge ◽  
Clock Gene Expression

Abstract In rodents, kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3V) of the preoptic area are considered to provide a major stimulatory input to the GnRH neuronal network that is responsible for triggering the preovulatory LH surge. Noradrenaline (NA) is one of the main modulators of GnRH release, and NA fibers are found in close apposition to kisspeptin neurons in the RP3V. Our objective was to interrogate the role of NA signaling in the kisspeptin control of GnRH secretion during the estradiol induced LH surge in ovariectomized rats, using prazosin, an α1-adrenergic receptor antagonist. In control rats, the estradiol-induced LH surge at 17 hours was associated with a significant increase in GnRH and kisspeptin content in the median eminence with the increase in kisspeptin preceding that of GnRH and LH. Prazosin, administered 5 and 3 hours prior to the predicted time of the LH surge truncated the LH surge and abolished the rise in GnRH and kisspeptin in the median eminence. In the preoptic area, prazosin blocked the increases in Kiss1 gene expression and kisspeptin content in association with a disruption in the expression of the clock genes, Per1 and Bmal1. Together these findings demonstrate for the first time that NA modulates kisspeptin synthesis in the RP3V through the activation of α1-adrenergic receptors prior to the initiation of the LH surge and indicate a potential role of α1-adrenergic signaling in the circadian-controlled pathway timing of the preovulatory LH surge.

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