A5073661592- Hypothalamic control of reproductive hormones
- Neuroendocrine regulation and behavior
- Circadian rhythm and melatonin
- Ovarian function and disorders
- Regulation of Appetite and Obesity
- Plant Reproductive Biology
- Neuropeptides and Animal Physiology
- Sleep and Wakefulness Research
- Estrogen and related hormone effects
- Growth Hormone and Insulin-like Growth Factors
- Reproductive Physiology in Livestock
- Neurotransmitter Receptor Influence on Behavior
- Stress Responses and Cortisol
- Photoreceptor and optogenetics research
- Receptor Mechanisms and Signaling
- Dietary Effects on Health
- Spaceflight effects on biology
- Electromagnetic Fields and Biological Effects
- Anatomy and Medical Technology
- Surgical Simulation and Training
- Menstrual Health and Disorders
- Neurobiology and Insect Physiology Research
- Neuroscience and Neuropharmacology Research
- Retinal Development and Disorders
- Neuroscience of respiration and sleep
Kent State University
2019-2025
University of Mississippi Medical Center
2013-2024
Salk Institute for Biological Studies
2024
Jackson Memorial Hospital
2013-2018
West Virginia University
2004-2016
University of Tübingen
2015
University of Edinburgh
2015
Western University
2006-2014
Institute of Neurobiology
2014
University of Michigan
1980-2013
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...
It is well established that overt circadian rhythms are permanently disrupted following lesions of the hamster hypothalamic suprachiasmatic nucleus (SCN). In present study, we show implantations brain grafts containing fetal SCN reestablish locomotor activity in adult hamsters previously made arrhythmic by lesions. The restoration free-running conditions constant darkness correlated with presence graft neuropeptides normally unlesioned hamsters, including vasoactive intestinal polypeptide...
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...
Bilateral lesions restricted to the medial nucleus of amygdala eliminate mating behavior in male hamster and severely diminish male's sniffing licking investigation female hamster's anogenital region. The results suggest that olfactory vomeronasal sensory information critical is processed nucleus, which an androgen-binding brain area. Thus may act as a relay through chemosensory influences activity preoptic-anterior hypothalamic junction bed stria terminalis, areas important mediation sexual...
Grafts of fetal tissue including the suprachiasmatic nucleus (SCN) hypothalamus restore locomotor rhythmicity to behaviorally arrhythmic, SCN-lesioned Syrian hamsters. We sought determine whether such transplants also reinstate endocrine rhythms in In Exp 1, SCN lesions interrupted estrous cycles a 14 h light, 10 dark photoperiod and constant dim red light (DD). grafts that reinstated behavioral circadian consistently failed reestablish cycles. After ovariectomy, estradiol implants triggered...
We used double label immunocytochemistry to examine the brains of ovariectomized ewes and determine whether GnRH, tyrosine hydroxylase-(TH), beta-endorphin-immunoreactive (IR) neurons contain IR-estrogen receptors (ER). Because their possible importance as a target for feedback actions estradiol, we also examined presence nuclear ER in LH-IR cells pars tuberalis pituitary. Although preoptic GnRH were frequently close proximity ER-IR cells, only one out approximately 1000 was found coexpress...
Abstract The luteinizing hormone‐releasing hormone (LHRH) system of the sheep brain was examined by light microscopic immunocytochemistry with thick, unembedded sections. We compared distribution and morphology LHRH cells their fibers in intact ovariectomized anestrous ewes, breeding season ewes during mid‐luteal phase estrous cycle. In all animals, a majority neurons were found medial preoptic area adjacent to organum vasculosum lamina terminalis. These formed continuum rostrally...
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...
• Thirty-six mucosal specimens were obtained with a biopsy instrument from the upper nasal septum of 12 human autopsy cases before en bloc removal entire olfactory area. Examination these 36 transmission electron microscopy demonstrated epithelium in only 17. A significant negative correlation (<i>r</i>=−.728) was noted between age subject and probability obtaining epithelium, supporting idea that mucosa is gradually replaced by respiratory aging. Using specimens, distribution reconstructed...
The ultrastructural localization of steroid hormone receptors has been made possible by the development immunocytochemical procedures using monoclonal antibodies. Estrogen receptor-immunoreactivity (ER-IR) in brain is present most abundantly neuronal nuclei when observed with light microscopy. However, we have also ER-IR perikarya and cytoplasmic processes neurons. To determine organelles which associated, developed a technique for visualization ER-IR. Ovariectomized guinea pigs were...
Recent data have demonstrated that mutations in the receptor for neurokinin B (NKB), NK-3 (NK3R), produce hypogonadotropic hypogonadism humans. These data, together with reports NKB expression increases after ovariectomy and postmenopausal women, led to hypothesis this tachykinin is an important stimulator of GnRH secretion. However, NK3R agonist, senktide, inhibited LH secretion rats mice. In study, we report senktide stimulates ewes. A dramatic increase concentrations levels close those...
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...
Neurotransplantation of the suprachiasmatic nucleus (SCN) was used to assess communication between central circadian pacemaker and peripheral oscillators in Syrian hamsters. Free-running rhythms <i>haPer1</i>, <i>haPer2</i>, <i>Bmal1</i> expression were documented liver, kidney, spleen, heart, skeletal muscle, adrenal medulla after 3 d or 11 weeks exposure constant darkness. Ablation SCN heterozygote <i>tau</i> mutants eliminated not only locomotor activity but also rhythmic these genes all...