scholarly journals Oxytocin Action at the Lactotroph Is Required for Prolactin Surges in Cervically Stimulated Ovariectomized Rats

Endocrinology ◽  
2007 ◽  
Vol 148 (10) ◽  
pp. 4649-4657 ◽  
Author(s):  
De’Nise T. McKee ◽  
Maristela O. Poletini ◽  
Richard Bertram ◽  
Marc E. Freeman
Keyword(s):  
Neuronal Activity ◽  
Dopaminergic Neurons ◽  
Bolus Injection ◽  
Ovariectomized Rats ◽  
Serum Prolactin ◽  
Before And After ◽  
Low Levels ◽  
Cervical Stimulation ◽  
Oxytocin Antagonist ◽  
The Mathematical Model

Cervical stimulation induces two daily rhythmic prolactin surges, nocturnal and diurnal, which persist for several days. We have shown that a bolus injection of oxytocin initiates a similar prolactin rhythm, which persists despite low levels of oxytocin after injection. This suggests that oxytocin may trigger the cervical stimulation-induced rhythmic prolactin surges. To investigate this hypothesis, we infused an oxytocin antagonist that does not cross the blood-brain barrier for 24 h before and after cervical stimulation and measured serum prolactin. We also measured dopaminergic neuronal activity because mathematical modeling predicted that this activity would be low in the presence of the oxytocin antagonist. We thus tested this hypothesis by measuring dopaminergic neuronal activity in the tuberoinfundibular, periventricular hypophyseal, and tuberohypophyseal dopaminergic neurons. Infusion of oxytocin antagonist before cervical stimulation abolished prolactin surges, and infusion of oxytocin antagonist after cervical stimulation abolished the diurnal and significantly decreased the nocturnal surges of prolactin. The rhythmic prolactin surges returned after the clearance of the oxytocin antagonist. Hypothalamic dopaminergic activity was elevated in antiphase with prolactin surges, and the antiphase elevation was abolished by the oxytocin antagonist in the tuberoinfundibular and tuberohypophyseal dopaminergic neurons, consistent with the mathematical model. These findings suggest that oxytocin is a physiologically relevant prolactin-releasing factor. However, the cervical stimulation-induced prolactin surges are maintained even in the absence of oxytocin actions at the lactotroph, which strongly suggests the maintenance of prolactin surges are not dependent upon oxytocin actions at the pituitary gland.

Role of the uterine cervix in inhibition of sexual behaviour in lactating rats

1985 ◽  
Vol 106 (2) ◽  
pp. 183-188 ◽  
Author(s):  
G. Forsberg ◽  
P. Södersten ◽  
P. Eneroth
Keyword(s):  
Sexual Behaviour ◽  
Uterine Cervix ◽  
Subsequent Treatment ◽  
Ovariectomized Rats ◽  
Serum Prolactin ◽  
Serum Progesterone ◽  
Concurrent Treatment ◽  
Lordosis Behaviour ◽  
Cervical Stimulation

ABSTRACT Treatment of ovariectomized rats with progesterone-filled constant-release implants, which increased serum progesterone concentrations to 99·4 ±5·0 nmol/l, facilitated the induction of lordosis behaviour by subsequent treatment with oestradiol benzoate (OB, 10 μg). Concurrent treatment with the dopamine receptor antagonist domperidone (two daily injections of 2·5 mg/rat), which increased serum prolactin concentrations, did not inhibit the behavioural response of ovariectomized progesterone-treated rats to OB. If the treatment was combined with stimulation of the uterine cervix it inhibited lordosis to a level which was comparable with that of progesterone–domperidone-treated rats, which had been ovariectomized and from which the pups had been removed on the day of parturition. The cervical stimulation did not increase the amount of prolactin secreted by the pituitary gland in response to an injection of domperidone. The behavioural effect of cervical stimulation was blocked by injecting an anaesthetic paste (0·1 ml lidocain–prilocain) intravaginally against the cervix. The effect of cervical stimulation, or of parturition, lasted only for a few days and sexual behaviour was inhibited during a prolonged period of lactation. Sucking by the pups on the nipples of the mother may be required for preventing sexual behaviour during the entire period of lactation. J. Endocr. (1985) 106, 183–188

scholarly journals α-Synuclein-induced dysregulation of neuronal activity contributes to murine dopamine neuron vulnerability

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Abeer Dagra ◽  
Douglas R. Miller ◽  
Min Lin ◽  
Adithya Gopinath ◽  
Fatemeh Shaerzadeh ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neuronal Activity ◽  
Dopaminergic Neurons ◽  
Prolonged Exposure ◽  
D2 Receptor ◽  
Neuronal Firing ◽  
Dopamine Neurons ◽  
Loss Of Function ◽  
Therapeutic Implications

AbstractPathophysiological damages and loss of function of dopamine neurons precede their demise and contribute to the early phases of Parkinson’s disease. The presence of aberrant intracellular pathological inclusions of the protein α-synuclein within ventral midbrain dopaminergic neurons is one of the cardinal features of Parkinson’s disease. We employed molecular biology, electrophysiology, and live-cell imaging to investigate how excessive α-synuclein expression alters multiple characteristics of dopaminergic neuronal dynamics and dopamine transmission in cultured dopamine neurons conditionally expressing GCaMP6f. We found that overexpression of α-synuclein in mouse (male and female) dopaminergic neurons altered neuronal firing properties, calcium dynamics, dopamine release, protein expression, and morphology. Moreover, prolonged exposure to the D2 receptor agonist, quinpirole, rescues many of the alterations induced by α-synuclein overexpression. These studies demonstrate that α-synuclein dysregulation of neuronal activity contributes to the vulnerability of dopaminergic neurons and that modulation of D2 receptor activity can ameliorate the pathophysiology. These findings provide mechanistic insights into the insidious changes in dopaminergic neuronal activity and neuronal loss that characterize Parkinson’s disease progression with significant therapeutic implications.

scholarly journals Effects of pre-extraction intermittent PTH administration on extraction socket healing in bisphosphonate administered ovariectomized rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jae-Young Kim ◽  
Hyo-Won Jang ◽  
Jung-In Kim ◽  
In-Ho Cha
Keyword(s):  
Tooth Extraction ◽  
Bisphosphonate Therapy ◽  
Ovariectomized Rats ◽  
Control Group ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Extraction Socket ◽  
Before And After ◽  
Socket Healing ◽  
Positive Effect

AbstractThe purpose of this study was to investigate the effect of administering intermittent parathyroid hormone (iPTH) before tooth extraction versus after tooth extraction on the risk of developing MRONJ in experimental animal model. Twenty-five ovariectomized rats received 6 weeks of bisphosphonate therapy. They were classified into 3 groups, based on the timing of the medication, as Control, Pre-PTH and Post-PTH groups. For Control group, normal saline was administered before and after tooth extraction. iPTH was administered during 4 weeks before tooth extraction for Pre-PTH group and after tooth extraction for Post-PTH group. The animals were euthanized 8 weeks after tooth extraction. Macroscopic, histological, micro-computed tomography (micro-CT), and histomorphometric examinations were conducted. The incidences of impaired healing were 11.11% both in Pre-PTH and Post-PTH groups, which was lower than the Control group (42.86%). Bone healing in the extraction socket, based on micro-CT and histomorphometry evaluations, was best in Post-PTH and worst in Control group. The Pre-PTH group showed moderate healing pattern. Despite of limitations in this study, the authors identified Pre-PTH group seems to have positive effect on extraction socket healing. With regard to timing, administering iPTH after tooth extraction was superior to applying it before tooth extraction.

INFLUENCE OF PHOTOPERIOD ON THYROTROPIN RELEASING HORMONE-INDUCED PROLACTIN RELEASE IN EWES

1983 ◽  
Vol 63 (1) ◽  
pp. 67-73 ◽  
Author(s):  
B. E. HOWLAND ◽  
D. SONYA ◽  
L. M. SANFORD ◽  
W. M. PALMER
Keyword(s):  
Thyrotropin Releasing Hormone ◽  
Day Length ◽  
Constant Light ◽  
Serum Prolactin ◽  
Prolactin Release ◽  
Blood Samples ◽  
Releasing Hormone ◽  
Before And After ◽  
Release Curve ◽  
Short Days

The influence of photoperiod on serum prolactin levels and prolactin release induced by thyrotropin releasing hormone (TRH) was determined in ewes maintained under the following lighting regimes: Room 1, lighting mimicked natural changes in photoperiod; Room 2, annual photoperiod changes condensed into 6 mo with short days in June; Room 3, same as Room 2 except photoperiod changed abruptly from 16.5 to 8.0 h on 21 Mar. and back to 16.5 h on 21 June; Room 4, constant light. Weekly blood samples were obtained from February to August. Additionally, blood samples were collected before and after treatment with 10 μg TRH on 19 May, 13 June, 27 June and 19 July. Prolactin levels were elevated in ewes exposed to long days or constant light. The mean of all pre-TRH samples was significantly correlated with stress-induced elevations in prolactin (highest pre-TRH value) (r = 0.72) and area under the TRH-induced release curve (r = 0.56). The prolactin release in response to TRH was greatest in ewes exposed to long days or constant light. Abrupt increase of day length elevated pretreatment prolactin levels (P < 0.01) and increased area under the response curve (P < 0.05). Key words: Photoperiod, TRH, prolactin, ewes

Implementation of a Standardized Perioperative Pain Management Protocol to Reduce Opioid Prescriptions in Otolaryngologic Surgery

2022 ◽  
pp. 019459982110711
Author(s):  
Michael T. Chang ◽  
M. Lauren Lalakea ◽  
Kimberly Shepard ◽  
Micah Saste ◽  
Amanda Munoz ◽  
...  
Keyword(s):  
Pain Management ◽  
Postoperative Pain ◽  
Lower Amount ◽  
Opioid Use ◽  
Protocol Implementation ◽  
Perioperative Pain ◽  
Management Protocol ◽  
Before And After ◽  
Perioperative Pain Management ◽  
Low Levels

Objective To evaluate the efficacy of implementing a standardized multimodal perioperative pain management protocol in reducing opioid prescriptions following otolaryngologic surgery. Study Design Retrospective cohort study. Setting County hospital otolaryngology practice. Methods A perioperative pain management protocol was implemented in adults undergoing otolaryngologic surgery. This protocol included preoperative patient education and a postoperative multimodal pain regimen stratified by pain level: mild, intermediate, and high. Opioid prescriptions were compared between patient cohorts before and after protocol implementation. Patients in the pain protocol were surveyed regarding pain levels and opioid use. Results We analyzed 210 patients (105 preprotocol and 105 postprotocol). Mean ± SD morphine milligram equivalents (MMEs) prescribed decreased from 132.5 ± 117.8 to 53.6 ± 63.9 ( P < .05) following protocol implementation. Mean MMEs prescribed significantly decreased ( P < .05) for each procedure pain tier: mild (107.4 to 40.5), intermediate (112.8 to 48.1), and high (240.4 to 105.0). Mean MMEs prescribed significantly decreased ( P < .05) for each procedure type: endocrine (105.6 to 44.4), facial plastics (225.0 to 50.0), general (160.9 to 105.7), head and neck oncology (138.6 to 77.1), laryngology (53.8 to 12.5), otology (77.5 to 42.9), rhinology (142.2 to 44.4), and trauma (288.0 to 24.5). Protocol patients reported a mean 1-week postoperative pain score of 3.4, used opioids for a mean 3.1 days, and used only 39% of their prescribed opioids. Conclusion Preoperative counseling and standardization of a multimodal perioperative pain regimen for otolaryngology procedures can effectively lower amount of opioid prescriptions while maintaining low levels of postoperative pain.

Excitotoxic acid lesions of the primate subthalamic nucleus result in reduced pallidal neuronal activity during active holding

1992 ◽  
Vol 68 (5) ◽  
pp. 1859-1866 ◽  
Author(s):  
I. Hamada ◽  
M. R. DeLong
Keyword(s):  
Subthalamic Nucleus ◽  
Neuronal Activity ◽  
Elbow Flexion ◽  
Ibotenic Acid ◽  
Excitatory Input ◽  
Behavioral Task ◽  
Discharge Rates ◽  
Before And After ◽  
The Mean ◽  
Flexion And Extension

1. To gain a better understanding of the pathophysiology of hemiballismus in primates, and to test directly the hypothesis that the subthalamopallidal projection is excitatory, we studied the effects of lesions of the subthalamic nucleus (STN) on neuronal activity in the globus pallidus (GP) of monkeys during performance of a motor behavioral task. 2. Animals were trained to position and hold a manipulandum to which torque pulses were applied, producing elbow flexion and extension. The activity of neurons in the external (GPe) and internal (GPi) segments of GP was recorded in two monkeys during task performance before and after STN lesions. The STN was lesioned by the fiber-sparing neurotoxins ibotenic acid and/or kainic acid. 3. After lesioning, the firing rate of neurons in both segments of GP, which was measured during the period of holding before torque application, was significantly decreased in both animals. The mean of discharge rates of GPi neurons decreased (P < 0.001) from 69.8 (n = 169, SD = 21.6) to 47.4 spikes/s (n = 180, SD = 22.6) after lesioning. The mean of discharge rates of GPe neurons decreased from 63.6 spikes/s (n = 218, SD = 25.1) before lesions to 41.0 spikes/s (n = 208, SD = 18.1) after lesioning. 4. These results provide further evidence that STN gives rise to a major excitatory input to both segments of the GP and support the hypothesis that dyskinesias result from decreased GPi output.

Low Levels of Prohibitin in Substantia Nigra Makes Dopaminergic Neurons Vulnerable in Parkinson’s Disease

2017 ◽  
Vol 55 (1) ◽  
pp. 804-821 ◽  
Author(s):  
Debashis Dutta ◽  
Nilufar Ali ◽  
Emili Banerjee ◽  
Raghavendra Singh ◽  
Amit Naskar ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Dopaminergic Neurons ◽  
Low Levels

Combining Neuroprotective Treatment of Embryonic Nigral Donor Tissue with Mild Hypothermia of the Graft Recipient

2005 ◽  
Vol 14 (5) ◽  
pp. 301-309 ◽  
Author(s):  
Jenny Karlsson ◽  
ÅSa Petersén ◽  
Gunilla Gidö ◽  
Tadeusz Wieloch ◽  
Patrik Brundin
Keyword(s):  
Graft Survival ◽  
Dopaminergic Neurons ◽  
Mild Hypothermia ◽  
Combined Treatment ◽  
Cell Number ◽  
Behavioral Recovery ◽  
Donor Tissue ◽  
Before And After ◽  
Neuroprotective Treatment ◽  
Graft Implantation

Around 80–95% of the immature dopaminergic neurons die when embryonic ventral mesencephalic tissue is transplanted. Cell death occurs both during the preparation of donor tissue and after graft implantation, but the effect of combining successful neuroprotective treatments before and after transplantation has not been extensively investigated. We therefore treated embryonic rat mesencephalic tissue with a combination of the lipid peroxidation inhibitor tirilazad mesylate (3 μM) and the caspase inhibitor Ac.YVAD.cmk (500 μM) and transplanted the tissue into hemiparkinsonian rats kept hypothermic (32–33°C) or normothermic (37°C) during, and 90 min following, graft surgery. Suspension cell number did not differ between untreated or tirilazad/YVAD-treated preparations prior to transplantation. When graft survival was evaluated 6 weeks after implantation, both tirilazad/YVAD pretreatment and mild hypothermia increased the survival of transplanted dopaminergic neurons. Approximately 50–57% of the embryonic dopaminergic neurons survived the dissociation and grafting procedure in rats rendered hypothermic, but there was no significant additive effect on graft survival with a combined treatment. All groups of rats exhibited behavioral recovery in the amphetamine-induced rotation test. There was a significantly enhanced functional capacity of grafts placed in hypothermic as compared to normothermic rats. However, tirilazad/YVAD pretreated implants did not afford greater behavioral improvement than control-treated grafts. Our results suggest that neuroprotective treatments administered prior to and immediately after neural graft implantation may under certain conditions rescue, at least in part, the same subset of dopaminergic neurons. The study also emphasizes the importance of the immediate time after grafting for transplant survival, with relevance both for primary mesencephalic implants and stem cell grafts.

Condition Monitoring Technology for Connecting Part and Sliding Part of Reciprocating Compressor

2017 ◽  
Author(s):  
Yoshifumi Mori ◽  
Takashi Saito ◽  
Yu Mizobe
Keyword(s):  
Mathematical Model ◽  
Natural Frequencies ◽  
Error Function ◽  
Connecting Rod ◽  
Value Analysis ◽  
Before And After ◽  
The Difference ◽  
Bending Modes ◽  
Parameter Values ◽  
The Mathematical Model

We focused on vibration characteristics of reciprocating compressors and constructed the mathematical model to calculate the natural frequencies and modes for crank angles and proposed a method to estimate the degree and the suspicious portion of failure by difference of temporal parameter values obtained using measuring data in operation and the mathematical model. In this paper, according to the proposed method, a case study is carried out using the field data, where the data were acquired before and after the failures occurred in the connecting parts of connecting rod, to prospect the difference between each parameter value for two operating states. Inspecting resonant characteristics each in the frequency response data relating to the natural frequencies for bending modes of the piston rod, we determined two resonant frequencies, which could correspond to the 1st and 2nd mode about bending of the piston rod. To equate the calculated each natural frequency from eigen value analysis based on the proposed model with each resonant frequency, we define the error function for the identified problem, namely optimum problem. In the identified results, it is found that some parameter values have much difference and the corresponding failure could occur around the connecting rod. We could show the possibility to detect both the change of the parameter values and the deterioration parts for two different kinds of the operating states by our proposed method.

Adoption-related feelings, loss, and curiosity about origins in adopted adolescents

2019 ◽  
Vol 24 (4) ◽  
pp. 876-891 ◽  
Author(s):  
Raquel Barroso ◽  
Maria Barbosa-Ducharne
Keyword(s):  
Point Of View ◽  
Birth Parents ◽  
Psychological Practice ◽  
New Family ◽  
Before And After ◽  
Low Levels ◽  
Birth Family

Adoption involves strong emotions. From the adoptee’s point of view, adoption means not only the gain of a new family but also inevitable losses. This study aims at analyzing adoption-related feelings, which include the feelings of loss and the ensuing curiosity about the birth family and pre-adoption life. A total of 81 adopted adolescents, aged 12–22, adopted at 4 years of age, on average, participated in this study. The data were collected using the Questionnaire of Adoption-related Feelings and the Adopted Adolescents Interview, which allowed for the identification of the experiences, feelings, and attitudes of the adopted adolescents regarding their story before and after adoption, and their feelings towards their birth family. The results showed that most participants did not identify adoption-related losses. Nevertheless, they acknowledged the existence of some aspects of their adoption story that made them feel sad and angry and could identify several difficulties associated with their adoptive status. Participants showed low levels of curiosity even if they were mostly curious about the reasons why they had been placed up for adoption. The adoptees’ feelings when thinking about their birth parents, the curiosity regarding their past, and their adoption-related losses predicted their feelings related to the adoption experience. Several implications for the psychological practice with adopted adolescents will be presented.

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