A5040630359- Hypothalamic control of reproductive hormones
- Neuroendocrine regulation and behavior
- Neuropeptides and Animal Physiology
- Neurotransmitter Receptor Influence on Behavior
- Regulation of Appetite and Obesity
- Ovarian function and disorders
- Plant Reproductive Biology
- Receptor Mechanisms and Signaling
- Sexual function and dysfunction studies
- Stress Responses and Cortisol
- Circadian rhythm and melatonin
- Estrogen and related hormone effects
- Sleep and Wakefulness Research
- Pain Mechanisms and Treatments
- Hormonal and reproductive studies
- Neuroscience and Neuropharmacology Research
- Neuroscience of respiration and sleep
- Sexual Differentiation and Disorders
- Spinal Cord Injury Research
- Memory and Neural Mechanisms
- Urinary Bladder and Prostate Research
- Pregnancy-related medical research
- Sexuality, Behavior, and Technology
- Spine and Intervertebral Disc Pathology
- Reproductive Physiology in Livestock
Kent State University
2019-2025
Radboud University Nijmegen
1996-2025
Catharina Ziekenhuis
2025
University of Mississippi Medical Center
2013-2021
Jackson Memorial Hospital
2013-2019
State Street (United States)
2015-2018
University of Michigan
2011-2016
Western University
2007-2016
West Virginia University
2016
Michigan United
2012-2015
Kisspeptin is a potent stimulator of GnRH secretion that has been implicated in the feedback actions ovarian steroids. In ewes, majority hypothalamic kisspeptin neurons are found arcuate nucleus (ARC), with smaller population located preoptic area. Most express estrogen receptor-alpha, as do set contain both dynorphin and neurokinin B (NKB), suggesting all three neuropeptides colocalized same cells. this study we tested hypothesis using dual immunocytochemistry also determined if MSH or...
Like leptin, the pancreatic hormone insulin is an important adiposity signal to brain. We report that hypothalamic melanocortin system target of actions regulate food intake and body weight. Hypothalamic neurons expressing receptors were found coexpress precursor molecule pro-opiomelanocortin (POMC), administration into third cerebral ventricle fasted rats increased expression POMC mRNA. Finally, a subthreshold dose antagonist SHU-9119 prevented reduction in caused by third-ventricular...
Reproductive activity in sheep is seasonal, being activated by short-day photoperiods and inhibited long days. During the nonbreeding season, GnRH secretion reduced both steroid-independent steroid-dependent (increased response to estradiol negative feedback) effects of photoperiod. Kisspeptin (also known as metastin) gonadotropin-inhibitory hormone (GnIH, or RFRP) are two RFamide neuropeptides that appear critical regulation reproductive neuroendocrine axis. We hypothesized expression...
Recent work in sheep has identified a neuronal subpopulation the arcuate nucleus that coexpresses kisspeptin, neurokinin B, and dynorphin (referred to here as KNDy cells) mediate negative feedback influence of progesterone on GnRH secretion. We hypothesized sex differences are due sexual dimorphism cells compared neuropeptide receptor immunoreactivity this between male female sheep. In addition, because B testosterone (T) during fetal life, we determined whether prenatal T exposure would...
Recent work has led to the hypothesis that kisspeptin/neurokinin B/dynorphin (KNDy) neurons in arcuate nucleus play a key role GnRH pulse generation, with kisspeptin driving release and neurokinin B (NKB) dynorphin acting as start stop signals, respectively. In this study, we tested by determining actions, if any, of four neurotransmitters found KNDy (kisspeptin, NKB, dynorphin, glutamate) on episodic LH secretion using local administration agonists antagonists receptors for these...
We tested the significance of a population lumbar spinothalamic cells for male sexual behavior in rats. These are positioned to relay ejaculation-related signals from reproductive organs brain, and they express neurokinin-1 receptors. Ablation these neurons by selective toxin SSP-saporin resulted complete disruption ejaculatory behavior. In contrast, other components remained intact. results suggest that this plays pivotal role generation may be part spinal ejaculation generator.
Endogenous opioid peptides (EOP) mediate progesterone-negative feedback in many species, but the specific EOP systems involved remain unresolved. We first addressed this question sheep by determining role of different receptor subtypes medial basal hypothalamus (MBH) and preoptic area (POA). Local administration antagonists to luteal phase ewes indicated that kappa-, not micro- or delta-, receptors inhibition LH secretion MBH. In contrast, both kappa- micro-, delta-receptor, increased pulse...
In the male Syrian hamster, mating is dependent on chemosensory and hormonal stimuli, interruption of either input prevents copulation. The medial amygdaloid nucleus (Me) a key nodal point in neural circuitry controlling sexual behavior because it relays both odor steroid cues. Me comprised two major subdivisions, anterior (MeA) posterior (MeP), which have distinct, although overlapping efferent projections. present study investigated afferents efferents MeA MeP by using combined anterograde...
Recent evidence has implicated neurokinin B (NKB) in the complex neuronal network mediating effects of gonadal steroids on regulation gonadotrophin-releasing hormone (GnRH) secretion. Because 3 receptor (NK3R) is considered to mediate NKB at cellular level, we determined distribution immunoreactive NK3R septal region, preoptic area (POA) and hypothalamus ewe. cells and/or fibres were found areas including bed nucleus stria terminalis, POA, anterior hypothalamic perifornical areas,...
Negative energy balance and insufficient adipose stores decrease the production of leptin, thereby diminishing leptin-supported secretion GnRH from hypothalamus promoting decreased reproductive function. Leptin acts via its receptor (LepRb) to support neuroendocrine axis, but nature location relevant LepRb neurons remain poorly understood. Possibilities include direct or indirect action leptin on hypothalamic neurons, kisspeptin (Kiss1) that are major regulators neurons. To evaluate these...
Abstract KNDy (kisspeptin/neurokinin B/dynorphin) neurons of the arcuate nucleus (ARC) appear to mediate negative feedback actions estradiol and are thought be key regulators pulsatile LH secretion. In ewe, may also involved with positive (E2) induce surge, but role kisspeptin in preoptic area (POA) remains unclear. The goal this study was identify which population(s) is (are) activated during surge response removal E2-negative feedback, using Fos as an index neuronal activation. Dual-label...
Drugs of abuse induce neuroplasticity in the natural reward pathway, specifically nucleus accumbens (NAc), thereby causing development and expression addictive behavior. Recent evidence suggests that rewards may cause similar changes NAc, suggesting drugs activate mechanisms plasticity shared with rewards, allowing for unique interplay between drug rewards. In this study, we demonstrate sexual experience male rats when followed by short or prolonged periods loss sex causes enhanced...
Kisspeptin-neurokinin B-dynorphin (KNDy) cells of the hypothalamus are a key component in neuroendocrine regulation GnRH secretion. Evidence sheep and other species suggests that dynorphin released by KNDy inhibits pulsatile secretion acting upon κ-opioid receptors (KOR). However, precise anatomical location neurochemical phenotype KOR-expressing remain unknown. To this end, we determined distribution KOR mRNA protein brains luteal phase ewes, using an ovine specific probe for situ...
Significance Hypothalamic oscillators that generate pulsatile patterns of hormone secretion represent a fundamental physiological feature regulating homeostatic systems. How individual cells within these neural ensembles and coordinate episodic activity resultant pulse is unknown. Recently, arcuate KNDy (kisspeptin/neurokinin B/dynorphin) were identified as critical component the gonadotrophin-releasing (GnRH) generator required for reproduction. Using in vivo calcium imaging neurons freely...
Recent evidence suggests that the dynorphin-kappa receptor opioid system acts to mediate inhibitory effect of progesterone (P) on GnRH pulse frequency during luteal phase ovine estrous cycle. It is known receptors (PRs) are required for actions P secretion. Therefore, if directly dynorphin (DYN) neurons, then these neurons should contain PRs. To test this hypothesis, we used a dual-label immunoperoxidase procedure visualize PRs and DYN in preoptic area (POA) hypothalamus ovary-intact ewes...