scholarly journals Photoperiod is involved in the regulation of seasonal breeding in male water voles (Arvicola terrestris)

2021 ◽  
Author(s):  
Kevin Poissenot ◽  
Areski Chorfa ◽  
Chantal Moussu ◽  
Anne-Charlotte Trouillet ◽  
Morgane Brachet ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Reproductive Activity ◽  
Reproductive Organs ◽  
Hypothalamic Nucleus ◽  
Arvicola Terrestris ◽  
Arvicola Amphibius ◽  
Reproductive Axis ◽  
Proximate Factor ◽  
Dorsomedial Hypothalamic Nucleus

Mammals living at temperate latitudes typically display annual cyclicity in their reproductive activity: births are synchronized when environmental conditions are most favorable. In a majority of these species, daylength is the main proximate factor used to anticipate seasonal changes and to adapt physiology. The brain integrates this photoperiodic signal through key hypothalamic structures, which regulate the reproductive axis. In this context, our study aims to characterize regulations that occur along the hypothalamo-pituitary-gonadal (HPG) axis in male fossorial water voles (Arvicola terrestris, also known as Arvicola amphibius) throughout the year and to further probe the implication of photoperiod in these seasonal regulations. Our monthly field monitoring shows dramatic seasonal changes in the morphology and activity of reproductive organs, as well as in the androgen-dependent lateral scent glands. Moreover, our data uncover seasonal variations at the hypothalamic level. During the breeding season, Kisspeptin expression in the arcuate nucleus (ARC) decreases, while RFRP3 expression in the dorsomedial hypothalamic nucleus (DMH) increases. Our follow-up laboratory study reveals activation of the reproductive axis and confirms a decrease in Kisspeptin expression in males exposed to a long photoperiod (summer condition) compared to those maintained under a short photoperiod (winter condition) that retain all features reminiscent of sexual inhibition. Altogether, our study characterizes neuroendocrine and anatomical markers of seasonal reproductive rhythmicity in male water voles and further suggests that these seasonal changes are chiefly driven by photoperiod.

scholarly journals Estradiol Down-Regulates RF-Amide-Related Peptide (RFRP) Expression in the Mouse Hypothalamus

Endocrinology ◽  
2011 ◽  
Vol 152 (4) ◽  
pp. 1684-1690 ◽  
Author(s):  
C. S. Molnár ◽  
I. Kalló ◽  
Z. Liposits ◽  
E. Hrabovszky
Keyword(s):  
Estrogen Receptor ◽  
Subcutaneous Administration ◽  
Hypothalamic Nucleus ◽  
Ovariectomized Mice ◽  
Reproductive Axis ◽  
17Β Estradiol ◽  
Dorsomedial Hypothalamic Nucleus ◽  
Low Levels ◽  
Nuclear Estrogen Receptor

Abstract In most mammals, RF-amide-related peptides are synthesized in the dorsomedial hypothalamic nucleus and regulate reproduction via inhibiting GnRH neurons and, possibly, adenohypophyseal gonadotrophs. In the present study, we investigated the possibility that RFRP-synthesizing neurons are involved in estrogen feedback signaling to the reproductive axis in mice. First, we used quantitative in situ hybridization and compared the expression of prepro-RFRP mRNA of ovariectomized mice, with and without 17β-estradiol (E2) replacement. Subcutaneous administration of E2 via silastic capsules for 4 d significantly down-regulated prepro-RFRP mRNA expression. The underlying receptor mechanism was investigated with immunohistochemistry. In ovariectomized mice, low levels of nuclear estrogen receptor (ER)-α immunoreactivity were detectable in 18.7 ± 3.8% of RFRP neurons. The majority of RFRP neurons showed no ER-α signal, and RFRP neurons did not exhibit ER-β immunoreactivity. Results of these studies indicate that RFRP is a negatively estradiol-regulated neurotransmitter/neuromodulator in mice. The estrogenic down-regulation of RFRP expression may contribute to estrogen feedback to the reproductive axis. The issue of whether E2 regulates RFRP neurons directly or indirectly remains open given that ER-α immunoreactivity is present only at low levels in a subset of these cells.

Changes in the Male Reproductive Organs of the Dugong, Dugong dugon (Sirenia: Dugondidae) with Age and Reproductive Activity

1984 ◽  
Vol 32 (6) ◽  
pp. 721 ◽  
Author(s):  
H Marsh ◽  
GE Heinsohn ◽  
TD Glover
Keyword(s):  
Reproductive Tract ◽  
Prostate Gland ◽  
Reproductive Activity ◽  
Reproductive Organs ◽  
Seminal Vesicles ◽  
Growth Layer ◽  
Male Reproductive Tract ◽  
Qualitative And Quantitative ◽  
Quantitative Examination ◽  
Testicular Histology

The anatomy and histology of the male reproductive tract of the dugong (Dugong dugon) is described. Each testis and its adjacent epididymis lie immediately caudal to the corresponding kidney. The seminal vesicles are large but there is no discrete prostate gland and the bulbo-urethral glands are also diffuse. Both qualitative and quantitative examination of the testes and epididymides of 59 males whose ages have been estimated from tusk dentinal growth layer counts indicate that the male dugong does not produce spermatozoa continuously, despite the absence of a distinct breeding season. Individual dugongs were observed with testes at all stages between complete quiescence and full spermatogenesis, and only 10 of the 40 mature males had fully spermatogenic testes and epididymides packed with spermatozoa. Androgenic and spermatogenic activity of the testes appeared to be in phase, but the testicular histology of some old males suggested that they may have been sterile for long periods.

scholarly journals Assessing the treatment of cannabidiolic acid methyl ester: a stable synthetic analogue of cannabidiolic acid on c-Fos and NeuN expression in the hypothalamus of rats

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Eric Murillo-Rodríguez ◽  
Diana Millán-Aldaco ◽  
Gloria Arankowsky-Sandoval ◽  
Tetsuya Yamamoto ◽  
Roger G. Pertwee ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Cannabis Sativa ◽  
Brain Area ◽  
Acid Methyl Ester ◽  
Hypothalamic Nucleus ◽  
Synthetic Analogue ◽  
Neuronal Nuclei ◽  
Cannabidiolic Acid ◽  
Dorsomedial Hypothalamic Nucleus ◽  
Psychotropic Compound

Abstract Background Cannabidiol (CBD), the non-psychotropic compound from Cannabis sativa, shows positive results on controlling several health disturbances; however, comparable data regarding additional chemical from C. sativa, such as cannabidiolic acid (CBDA), is scarce due to its instability. To address this limitation, a stable CBDA analogue, CBDA methyl ester (HU-580), was synthetized and showed CBDA-like effects. Recently, we described that HU-580 increased wakefulness and wake-related neurochemicals. Objective To extend the comprehension of HU-580´s properties on waking, the c-Fos and NeuN expression in a wake-linked brain area, the hypothalamus was evaluated. Methods c-Fos and NeuN expression in hypothalamic sections were analyzed after the injections of HU-580 (0.1 or 100 μg/kg, i.p.). Results Systemic administrations of HU-580 increased c-Fos and neuronal nuclei (NeuN) expression in hypothalamic nuclei, including the dorsomedial hypothalamic nucleus dorsal part, dorsomedial hypothalamic nucleus compact part, and dorsomedial hypothalamic nucleus ventral part. Conclusion HU-580 increased c-Fos and NeuN immunoreactivity in hypothalamus nuclei suggesting that this drug might modulate the sleep–wake cycle by engaging the hypothalamus.

scholarly journals Long-Term Follow-Up of a Female Patient Treated with Olaparib—Hope for a Long Life without Relapse?

2021 ◽  
Vol 18 (7) ◽  
pp. 3430
Author(s):  
Mateusz Kozłowski ◽  
Katarzyna Nowak ◽  
Aneta Cymbaluk-Płoska
Keyword(s):  
Ovarian Cancer ◽  
Parp Inhibitor ◽  
Brca1 Gene ◽  
High Specificity ◽  
Reproductive Organs ◽  
Platinum Based Chemotherapy ◽  
Long Term Follow Up ◽  
History Of ◽  
Advanced Stages

Ovarian cancer is one of the most common cancers of the reproductive organs. As there are no symptoms in the early stages, it is mainly detected in the advanced stages. Even then, the symptoms are non-specific and include, for example, abdominal pain, early satiety, or changes in bowel habits. Both biochemical marker levels and imaging studies are used in the initial diagnosis. However, it should be emphasized that they are not characterized by high specificity. Treatment is multistage, and usually first-line debulking surgery is used followed by platinum-based chemotherapy. Here we present a clinical case of a 56-year-old female, a carrier of a mutation in the BRCA1 gene, with a history of breast cancer and with recurrent epithelial ovarian cancer. The patient was qualified for treatment with a PARP inhibitor and is currently undergoing treatment with olaparib. In the patient’s follow up of 50 months to date, there has been no recurrence of cancer. Few side effects have been observed, and the most serious one that can be effectively treated is anemia. On the basis of the described case, the authors concluded that olaparib treatment is effective, relatively safe, and does not significantly affect daily functioning.

Spatial and temporal variation in littoral-zone benthic invertebrates from three south-central Ontario lakes

1995 ◽  
Vol 52 (7) ◽  
pp. 1406-1420 ◽  
Author(s):  
R. A. Reid ◽  
K. M. Somers ◽  
S. M. David
Keyword(s):  
Temporal Variation ◽  
Benthic Invertebrates ◽  
Seasonal Changes ◽  
Littoral Zone ◽  
Spatial And Temporal Variation ◽  
South Central ◽  
Temporal Factors ◽  
Follow Up Studies ◽  
Spatial Differences

Surveys of benthic invertebrates have revealed patterns attributed to the impacts of acid deposition. Unfortunately, these patterns may be confounded by temporal variation that will affect follow-up studies of the recovery of these communities. Here, we assess spatial and temporal variation in time-limited, kick-and-sweep collections of littoral-zone benthos. Spatial variation comprised five sites representing the predominant nearshore substrates in each of three lakes. Temporal variation spanned a different scale in each lake with five sites sampled: (i) twice on the same day, (ii) once a week for 3 weeks, and (iii) four times through the ice-free season. Variation was quantified using a model II analysis of variance. Spatial differences predominated in same-day samples (60.4% of the variation on average) and those collected over a 3-week period (46.1%). In contrast, samples collected over the ice-free season revealed that spatial and temporal factors accounted for 9.4 and 25.6% of the variation. We conclude that our collections of littoral macrobenthos are highly repeatable if sampling is restricted to short periods (e.g., 3 weeks). Surveys spanning longer periods may incorporate considerable temporal variation from seasonal changes in abundance.

scholarly journals The Dorsomedial Hypothalamic Nucleus Is Not Necessary for the Expression of Circadian Food-Anticipatory Activity in Rats

2007 ◽  
Vol 22 (6) ◽  
pp. 467-478 ◽  
Author(s):  
Glenn J. Landry ◽  
Glenn R. Yamakawa ◽  
Ian C. Webb ◽  
Rhiannon J. Mear ◽  
Ralph E. Mistlberger
Keyword(s):  
Hypothalamic Nucleus ◽  
Food Anticipatory Activity ◽  
Dorsomedial Hypothalamic Nucleus ◽  
Anticipatory Activity

scholarly journals The deletion of glucagon-like peptide-1 receptors expressing neurons in the dorsomedial hypothalamic nucleus disrupts the diurnal feeding pattern and induces hyperphagia and obesity

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yuko Maejima ◽  
Shoko Yokota ◽  
Masaru Shimizu ◽  
Shoichiro Horita ◽  
Daisuke Kobayashi ◽  
...  
Keyword(s):  
Nucleus Tractus Solitarius ◽  
Physiological Role ◽  
Feeding Pattern ◽  
Hypothalamic Nucleus ◽  
Acid Decarboxylase ◽  
Mrna Levels ◽  
Dorsomedial Hypothalamic Nucleus ◽  
Fos Expression ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Abstract Background Feeding rhythm disruption contributes to the development of obesity. The receptors of glucagon-like peptide-1 (GLP-1) are distributed in the wide regions of the brain. Among these regions, GLP-1 receptors (GLP-1R) are expressed in the dorsomedial hypothalamic nucleus (DMH) which are known to be associated with thermogenesis and circadian rhythm development. However, the physiological roles of GLP-1R expressing neurons in the DMH remain elusive. Methods To examine the physiological role of GLP-1R expressing neurons in the DMH, saporin-conjugated exenatide4 was injected into rat brain DMH to delete GLP-1R-positive neurons. Subsequently, locomotor activity, diurnal feeding pattern, amount of food intake and body weight were measured. Results This deletion of GLP-1R-positive neurons in the DMH induced hyperphagia, the disruption of diurnal feeding pattern, and obesity. The deletion of GLP-1R expressing neurons also reduced glutamic acid decarboxylase 67 and cholecystokinin A receptor mRNA levels in the DMH. Also, it reduced the c-fos expression after refeeding in the suprachiasmatic nucleus (SCN). Thirty percent of DMH neurons projecting to the SCN expressed GLP-1R. Functionally, refeeding after fasting induced c-fos expression in the SCN projecting neurons in the DMH. As for the projection to the DMH, neurons in the nucleus tractus solitarius (NTS) were found to be projecting to the DMH, with 33% of those neurons being GLP-1-positive. Refeeding induced c-fos expression in the DMH projecting neurons in the NTS. Conclusion These findings suggest that GLP-1R expressing neurons in the DMH may mediate feeding termination. In addition, this meal signal may be transmitted to SCN neurons and change the neural activities.

Sign in / Sign up

Export Citation Format

Share Document