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Scientific Reports Nov 2023Despite the prevalent expression of freezing behavior following Pavlovian fear conditioning, a growing body of literature suggests potential sex differences in defensive...
Despite the prevalent expression of freezing behavior following Pavlovian fear conditioning, a growing body of literature suggests potential sex differences in defensive responses. Our study investigated how female defensive behaviors are expressed in different threat situations and modulated by the estrous cycle. We aimed to compare freezing and flight-like responses during the acquisition and retrieval of fear conditioning using two distinct unconditioned stimuli (US) in two different spatial configurations: (1) electrical footshock (FUS) in a small, conventional enclosure with a grid floor, and (2) a predator-like robot (PUS) in a spacious, open arena. Fear conditioning with FUS showed no substantial differences between male and female rats of two different estrous cycles (proestrus and diestrus) in the levels of freezing and flight. However, when PUS was employed, proestrus female rats showed significantly more flight responses to the CS during both acquisition and the retrieval compared to the male and diestrus female rats. Taken together, our findings suggest that hormonal influences on the choice of defensive strategies in threat situations are significantly modulated by both the type of US and the spatial configuration of the environment.
Topics: Rats; Female; Male; Animals; Conditioning, Classical; Estrous Cycle; Fear; Proestrus; Behavior, Animal
PubMed: 38017045
DOI: 10.1038/s41598-023-47591-x -
Reproductive Sciences (Thousand Oaks,... Oct 2022Oviductal extracellular vesicles (OEVs) play an important role in fertilization and embryo development. However, it remains largely unknown whether the size and protein...
Oviductal extracellular vesicles (OEVs) play an important role in fertilization and embryo development. However, it remains largely unknown whether the size and protein cargo of OEVs change during the estrous cycle in mice. This study analyzed the changes in the size distribution and protein cargo of OEVs at four stages of the estrous cycle in mice. The distribution widths of OEVs according to the estrous cycle stage were as follows: proestrus, 20-690 nm in diameter, with two peaks at 50 and 250 nm; estrus, 22-420 nm in diameter, with two peaks at 40 and 200 nm; metestrus, 30-70 nm diameter, with a single peak at 40 nm; and diestrus, 10-26 nm diameter, with a single peak at 20 nm. The estrogen receptor (ER) level in OEVs at the proestrus stage differed significantly from that at estrus (P = 0.013) and diestrus (P = 0.005). The levels of CD9 and Hsc70 fluctuated across the four stages, although with no significant differences. Furthermore, OEVs were observed among the cilia and microvilli of epithelial cells at the proestrus, estrus, and diestrus stages, but not at the metestrus stage. The number of observed OEVs was the highest at the proestrus stage, followed by the estrus, and the diestrus stage. Endosomes were also observed at the estrus and diestrus stages. The change of the OEV size and ER cargo is associated with the estrous cycle in mice. Our findings increase the understanding of the physiological characteristics of OEVs, which may have clinical applications.
Topics: Animals; Estrous Cycle; Extracellular Vesicles; Fallopian Tubes; Female; Humans; Mice; Oviducts; Receptors, Estrogen
PubMed: 35137347
DOI: 10.1007/s43032-022-00862-w -
Biochemical Pharmacology Jul 2022Activation of the rostral ventrolateral medulla (RVLM) cannabinoid receptor-1 (CBR) causes neuronal nitric oxide synthase (nNOS)-dependent increases in sympathetic...
Activation of the rostral ventrolateral medulla (RVLM) cannabinoid receptor-1 (CBR) causes neuronal nitric oxide synthase (nNOS)-dependent increases in sympathetic activity, blood pressure (BP) and heart rate (HR) in male rats. However, it remains unknown if the CBR-mediated neurochemical and cardiovascular responses are influenced by the ovarian sex hormones, particularly estrogen (E). Therefore, we studied the effects of intra-RVLM CBR activation (WIN 55,212-2) on BP and HR in conscious female rats under the following hormonal states: (1) highest E level (proestrus sham-operated, SO); (2) E-deprivation (ovariectomized, OVX); (3) OVX with E replacement (OVXE2). Intra-RVLM WIN55,212-2 elicited dose (100-400 pmol) dependent pressor and tachycardic responses, in OVX rats, which replicated the reported responses in male rats. However, in SO and OVXE2 rats, the CBR-mediated pressor response was attenuated and the tachycardic response reverted to bradycardic response. The neurochemical findings suggested a key role for the upregulated RVLM sympathoexcitatory molecules phosphorated protein kinase B, phosphorated nNOS and reactive oxygen species in the exaggerated CBR-mediated BP and HR responses in OVX rats, and an E-dependent dampening of these responses. The intra-RVLM WIN55212-2-evoked cardiovascular and neurochemical responses were CBR-mediated because they were attenuated by prior CBR blockade (AM251). Our findings suggest that attenuation of RVLM neuroexcitation and oxidative stress underlies the protection conferred by E, in female rats, against the CBR-mediated adverse cardiovascular effects.
Topics: Animals; Benzoxazines; Blood Pressure; Estrogens; Female; Heart Rate; Male; Medulla Oblongata; Morpholines; Naphthalenes; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Vasoconstrictor Agents
PubMed: 35617998
DOI: 10.1016/j.bcp.2022.115102 -
Physiological Reports Sep 2022The pattern of gonadotropin secretion along the estrous cycle was elegantly described in rats. Less information exists about the pattern of gonadotropin secretion in...
The pattern of gonadotropin secretion along the estrous cycle was elegantly described in rats. Less information exists about the pattern of gonadotropin secretion in gonad-intact mice, particularly regarding the follicle-stimulating hormone (FSH). Using serial blood collections from the tail-tip of gonad-intact C57BL/6 mice on the first day of cornification (transition from diestrus to estrus; hereafter called proestrus), we observed that the luteinizing hormone (LH) and FSH surge cannot be consistently detected since only one out of eight females (12%) showed increased LH levels. In contrast, a high percentage of mice (15 out of 21 animals; 71%) exhibited LH and FSH surges on the proestrus when a single serum sample was collected. Mice that exhibited LH and FSH surges on the proestrus showed c-Fos expression in gonadotropin-releasing hormone- (GnRH; 83.4% of co-localization) and kisspeptin-expressing neurons (42.3% of co-localization) of the anteroventral periventricular nucleus (AVPV). Noteworthy, mice perfused on proestrus, but that failed to exhibit LH surge, showed a smaller, but significant expression of c-Fos in GnRH (32.7%) and AVPV (14.0%) neurons. Finally, 96 serial blood samples were collected hourly in eight regular cycling C57BL/6 females to describe the pattern of LH and FSH secretion along the estrous cycle. Small elevations in LH and FSH levels were detected at the time expected for the LH surge. In summary, the present study improves our understanding of the pattern of gonadotropin secretion and the activation of central components of the hypothalamic-pituitary-gonadal axis along the estrous cycle of C57BL/6 female mice.
Topics: Animals; Estrous Cycle; Female; Follicle Stimulating Hormone; Gonadotropin-Releasing Hormone; Kisspeptins; Luteinizing Hormone; Mice; Mice, Inbred C57BL; Proto-Oncogene Proteins c-fos; Rats
PubMed: 36065891
DOI: 10.14814/phy2.15460 -
Scientific Reports Mar 2017Gel-forming mucins are macromolecules produced by goblet cells and responsible for the mucus gel formation. Changes in goblet cell density and in gel-forming mucin...
Gel-forming mucins are macromolecules produced by goblet cells and responsible for the mucus gel formation. Changes in goblet cell density and in gel-forming mucin production have emerged as sensitive indicators for mucosal diseases. A Muc5b-GFP tagged reporter mouse was used to assess Muc5b production in mouse tissues by immunofluorescence microscopy and fluorescent activity using stereromicroscopy and probe-based confocal laser endomicroscopy. Muc5b production was followed longitudinally by recording the fluorescent activity in vagina and in embryonic lung explants under stimulation by interleukin 13. We show that the GFP is easily visualized in the mouse adult ear, nose, trachea, gallbladder, and cervix. Live Muc5b is also easily monitored in the nasal cavity, trachea and vagina where its production varies during the estrus cycle with a peak at the proestrus phase and in pregnant mice. Explant culture of reporter mouse embryonic whole lung shows that interleukin 13 stimulates Muc5b production. The transgenic Muc5b-GFP mouse is unique and suitable to study the mechanisms that regulate Muc5b production/secretion and mucous cell differentiation by live imaging and can be applied to test drug efficacy in mucosal disease models.
Topics: Animals; Female; Goblet Cells; Humans; Interleukin-13; Lung; Mice; Mice, Transgenic; Molecular Imaging; Mucin-5B; Mucus; Nasal Cavity; Organ Culture Techniques; Trachea; Vagina
PubMed: 28294161
DOI: 10.1038/srep44591 -
Journal of Neurochemistry Apr 2020Adenosine is a ubiquitous neuromodulator that plays a role in sleep, vasodilation, and immune response and manipulating the adenosine system could be therapeutic for...
Adenosine is a ubiquitous neuromodulator that plays a role in sleep, vasodilation, and immune response and manipulating the adenosine system could be therapeutic for Parkinson's disease or ischemic stroke. Spontaneous transient adenosine release provides rapid neuromodulation; however, little is known about the effect of sex as a biological variable on adenosine signaling and this is vital information for designing therapeutics. Here, we investigate sex differences in spontaneous, transient adenosine release using fast-scan cyclic voltammetry to measure adenosine in vivo in the hippocampus CA1, basolateral amygdala, and prefrontal cortex. The frequency and concentration of transient adenosine release were compared by sex and brain region, and in females, the stage of estrous. Females had larger concentration transients in the hippocampus (0.161 ± 0.003 µM) and the amygdala (0.182 ± 0.006 µM) than males (hippocampus: 0.134 ± 0.003, amygdala: 0.115 ± 0.002 µM), but the males had a higher frequency of events. In the prefrontal cortex, the trends were reversed. Males had higher concentrations (0.189 ± 0.003 µM) than females (0.170 ± 0.002 µM), but females had higher frequencies. Examining stages of the estrous cycle, in the hippocampus, adenosine transients are higher concentration during proestrus and diestrus. In the cortex, adenosine transients were higher in concentration during proestrus, but were lower during all other stages. Thus, sex and estrous cycle differences in spontaneous adenosine are complex, and not completely consistent from region to region. Understanding these complex differences in spontaneous adenosine between the sexes and during different stages of estrous is important for designing effective treatments manipulating adenosine as a neuromodulator.
Topics: Adenosine; Animals; Brain; Estrous Cycle; Female; Male; Rats; Rats, Sprague-Dawley; Sex Characteristics
PubMed: 32040198
DOI: 10.1111/jnc.14981 -
Frontiers in Bioscience (Landmark... Jun 2016The oviductal epithelial membrane releases into the luminal environment extracellular vesicles (EVs) which are pleomorphic in nature and fall into two categories:... (Review)
Review
The oviductal epithelial membrane releases into the luminal environment extracellular vesicles (EVs) which are pleomorphic in nature and fall into two categories: exosomes and microvesicles. Both of these membrane vesicles are referred to as Oviductosomes (OVS), and to date have been identified in the murine and bovine species. Bovine EVs derived in vivo and from in vitro culture show differences in their protein cargo which includes CD9 and HSC70 biochemical markers and fertility-modulating proteins such as oviduct-specific glycoprotein (OVGP) and Plasma Membrane Ca(2+) ATPase 4 (PMCA4). PMCA4, an essential multifunctional sperm protein, is hormonally-regulated with elevated levels seen in proestrus/estrus. OVS deliver PMCA4 to sperm via a fusogenic mechanism involving the interaction between CD9 and integrins which are present on their surfaces. Studies of OVS are needed to determine the components of their cargoes and their interaction with oocytes and the very early embryo. Based on our present knowledge of their interaction with sperm, they are expected to play pivotal roles in regulating fertility and promise to inform the current IVF practice.
Topics: Animals; Blastocyst; Cell-Derived Microparticles; Exosomes; Fallopian Tubes; Female; Humans; Male; Plasma Membrane Calcium-Transporting ATPases; Pregnancy; Spermatozoa
PubMed: 27100506
DOI: 10.2741/4456 -
Pharmacology Research & Perspectives Jun 2022Sexual dimorphisms are observed in cannabinoid pharmacology. It is widely reported that female animals are more sensitive to the cataleptic, hypothermic,... (Review)
Review
Sexual dimorphisms are observed in cannabinoid pharmacology. It is widely reported that female animals are more sensitive to the cataleptic, hypothermic, antinociceptive, and anti-locomotive effects of cannabinoid receptor agonists such as CP55,940. Despite awareness of these sex differences, there is little consideration for the pharmacodynamic differences within females. The mouse estrus cycle spans 4-5 days and consists of four sex hormone-mediated phases: proestrus, estrus, metestrus, and diestrus. The endocannabinoid system interacts with female sex hormones including β-estradiol, which may influence receptor expression throughout the estrus cycle. In the current study, sexually mature female C57BL/6 mice in either proestrus or metestrus were administered either 1 mg/kg i.p. of the cannabinoid receptor agonist CP55,940 or vehicle. Mice then underwent the tetrad battery of behavioral assays measuring catalepsy, internal body temperature, thermal nociception, and locomotion. Compared with female mice in metestrus, those in proestrus were more sensitive to the anti-nociceptive effects of CP55,940. A similar trend was observed in CP55,940-induced catalepsy; however, this difference was not significant. As for cannabinoid receptor expression in brain regions underlying antinociception, the spine tissue of proestrus mice that received CP55,940 exhibited increased expression of cannabinoid receptor type 1 relative to treatment-matched mice in metestrus. These results affirm the importance of testing cannabinoid effects in the context of the female estrus cycle.
Topics: Animals; Cannabinoid Receptor Agonists; Cannabinoids; Catalepsy; Estrus; Female; Male; Mice; Mice, Inbred C57BL; Receptors, Cannabinoid
PubMed: 35466560
DOI: 10.1002/prp2.950 -
BMC Pharmacology & Toxicology Nov 2023The illicit use and abuse of gamma-hydroxybutyric acid (GHB) occurs due to its sedative/hypnotic and euphoric effects. Currently, there are no clinically available...
BACKGROUND
The illicit use and abuse of gamma-hydroxybutyric acid (GHB) occurs due to its sedative/hypnotic and euphoric effects. Currently, there are no clinically available therapies to treat GHB overdose, and care focuses on symptom treatment until the drug is eliminated from the body. Proton- and sodium-dependent monocarboxylate transporters (MCTs (SLC16A) and SMCTs (SLC5A)) transport and mediate the renal clearance and distribution of GHB. Previously, it has been shown that MCT expression is regulated by sex hormones in the liver, skeletal muscle and Sertoli cells. The focus of the current study is to evaluate GHB toxicokinetics and renal monocarboxylate transporter expression over the estrus cycle in females, and in the absence of male and female sex hormones.
METHODS
GHB toxicokinetics and renal transporter expression of MCT1, SMCT1 and CD147 were evaluated in females over the estrus cycle, and in ovariectomized (OVX) female, male and castrated (CST) male rats. GHB was administered iv bolus (600 and 1000 mg/kg) and plasma and urine samples were collected for six hours post-dose. GHB concentrations were quantified using a validated LC/MS/MS assay. Transporter mRNA and protein expression was quantified by qPCR and Western Blot.
RESULTS
GHB renal clearance and AUC varied between sexes and over the estrus cycle in females with higher renal clearance and a lower AUC in proestrus females as compared to males (intact and CST), and OVX females. We demonstrated that renal MCT1 membrane expression varies over the estrus cycle, with the lowest expression observed in proestrus females, which is consistent with the observed changes in GHB renal clearance.
CONCLUSIONS
Our results suggest that females may be less susceptible to GHB-induced toxicity due to decreased exposure resulting from increased renal clearance, as a result of decreased renal MCT1 expression.
Topics: Rats; Male; Female; Animals; Sodium Oxybate; Rats, Sprague-Dawley; Toxicokinetics; Tandem Mass Spectrometry; Monocarboxylic Acid Transporters; Gonadal Steroid Hormones
PubMed: 37919807
DOI: 10.1186/s40360-023-00700-y -
Frontiers in Bioscience (Landmark... Dec 2021Myocardial infarction is the leading cause of death in women worldwide. Several studies have shown that estrogens play a cardioprotective role in women by decreasing...
INTRODUCTION
Myocardial infarction is the leading cause of death in women worldwide. Several studies have shown that estrogens play a cardioprotective role in women by decreasing reactive oxygen species (ROS) and increasing nitric oxide (NO). The aim of this work was to determine whether the evolution of myocardial infarction depends on the phase of the estrous cycle.
METHODS
Female Wistar rats were randomized into the following groups with an (n = 7 per group): (1) ovariectomized (OVX-sham); (2) OVX-48 h coronary occlusion (CO); (3) OVX-2 w CO; (4) proestrus-sham; (5) proestrus-48 h CO; (6) proestrus-2 w CO; (7) estrus-sham; (8) estrus-48 h CO; and (9) estrus-2 w CO. We measured the percentage of myocardial necrosis, cardiac hypertrophy, hemodynamic parameters, and the production of NO and ROS, after acute and chronic myocardial infarction was induced in proestrus or estrus or ovariectomized female rats.
RESULTS
The infarct area was reduced in the proestrus groups, while it was increased in the estrus and OVX groups. The left ventricular systolic pressure (LVSP) and ± dP/dt were reduced, but left ventricular diastolic pressure (LVDP) was increased in the OVX groups. NO was increased in the OVX + CO and estrus + CO groups. Production of ROS was increased in OVX rats after myocardial infarction but remained unchanged in proestrus and estrus.
CONCLUSION
The phase of the estrous cycle in which the myocardial infarction occurs is important. When the coronary occlusion occurs during the proestrus phase, it prevents changes in cardiac function, the development of hypertrophy, oxidative stress and changes in NO levels, and reduces the extent of infarction.
Topics: Animals; Female; Humans; Rats; Estrous Cycle; Myocardial Infarction; Nitric Oxide; Ovariectomy; Rats, Wistar; Reactive Oxygen Species
PubMed: 34994158
DOI: 10.52586/5037