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1.
Neuropharmacology ; 256: 110009, 2024 May 31.
Article in English | MEDLINE | ID: mdl-38823577

ABSTRACT

Water is critical for survival and thirst is a powerful way of ensuring that fluid levels remain in balance. Overconsumption, however, can have deleterious effects, therefore optimization requires a need to balance the drive for water with the satiation of that water drive. This review will highlight our current understanding of how thirst is both generated and quenched, with particular focus on the roles of angiotensin II, glucagon like-peptide 1, and estradiol in turning on and off the thirst drive. Our understanding of the roles these bioregulators play has benefited from modern behavioral analyses, which have improved the time resolution of intake measures, allowing for attention to the details of the patterns within a bout of intake. This has led to behavioral interpretation in ways that are helpful in understanding the many controls of water intake and has expanded our understanding beyond the dichotomy that something which increases water intake is simply a "stimulator" while something that decreases water intake is simply a "satiety" factor. Synthesizing the available information, we describe a framework in which thirst is driven directly by perturbations in fluid intake and indirectly modified by several bioregulators. This allows us to better highlight areas that are in need of additional attention to form a more comprehensive understanding of how the system transitions between states of thirst and satiety.

2.
Int J Lang Commun Disord ; 59(1): 354-368, 2024.
Article in English | MEDLINE | ID: mdl-37715532

ABSTRACT

BACKGROUND: Parents play a central role in the treatment of childhood stuttering. Addressing parental attitudes toward stuttering is helpful therapeutically. The extent to which differences in attitudes toward stuttering exist on the basis of sex, geographical region and parental status (e.g., parent of a stuttering child, parent of a nonstuttering child, nonparent) is unclear. Many studies investigating such factors have used the Public Opinion Survey of Human Attributes-Stuttering (POSHA-S) questionnaire. A large POSHA-S database has collected responses from over 20 000 people from 49 countries. AIMS: The aim of this study was to use the POSHA-S database to examine the extent to which the following variables influence attitudes toward stuttering: (a) parents' sex (mothers vs. fathers), (b) geographic region (Middle East vs. Europe and North America), (c) parents' children (stuttering vs. nonstuttering) and (d) parental status (parents versus nonparents). METHODS & PROCEDURES: Data used in this study were extracted from selected, relevant studies that administered the POSHA-S to respondents. The Overall Stuttering Scores were compared on the basis of sex and parent status (i.e., mothers and fathers; nonparent women and men) and were then compared within and across the two geographical areas. Group comparisons were performed using analysis of variance followed by independent t tests, and Cohen's d was calculated to determine effect sizes. OUTCOMES & RESULTS: Statistically significant differences were observed upon the basis of geographical region. In general, male parents and nonparents tend to have more positive stuttering attitudes among the Middle Eastern samples while female parents and nonparents tend to show more positive attitudes in European and North American samples in the POSHA-S database. Effect sizes were small for all comparisons. CONCLUSIONS & IMPLICATIONS: The effect of geographic region and culture may predict sex-based differences among mothers' and fathers' attitudes toward stuttering; however, the clinical significance is unclear. Additional research is needed to better understand how children who stutter are affected by their parents' attitudes toward stuttering. WHAT THIS PAPER ADDS: What is already known on this subject The research clearly indicates that attitudes toward stuttering vary according to geographical region. Less clear is whether mothers and fathers from geographically diverse backgrounds hold different attitudes toward stuttering and the extent to which parental status (being a parent, parent of a child who stutters or nonparent) affects attitudes toward stuttering. What this study adds This study's findings confirm that geographical differences do influence attitudes toward stuttering. Male parents and nonparents tend to have equal or more positive attitudes toward stuttering in Middle Eastern samples, whereas non-Middle Eastern female parents and nonparents tend to show hold more positive attitudes. What are the clinical implications of this work? In addition to being culturally sensitive when working with parents of children who stutter, clinicians should also consider that mothers and fathers may have some differences in attitudes and behaviours toward their child's stuttering. These differences should be considered when designing treatment plans. It should also be noted that, despite statistical significance, the effect sizes in this study were low, suggesting that further research as well as close collaboration with parents of children who stutter is warranted.


Subject(s)
Stuttering , Child , Humans , Male , Female , Stuttering/therapy , Mothers , Europe , Middle East , Surveys and Questionnaires , North America , Fathers
3.
Glob Health Sci Pract ; 11(6)2023 Dec 22.
Article in English | MEDLINE | ID: mdl-38124019

ABSTRACT

Comprehensive sexual education (CSE) is an important approach for health promotion dissemination in schools, particularly when delivered in participatory ways that are sport based, peer or near-peer led, and include concepts of gender and power dynamics. Sufficient attendance at CSE sessions is critical to ensure content exposure and build potential for impact. This article details implementation lessons from the delivery of an after-school, near-peer-led CSE program called SKILLZ during a cluster randomized controlled trial among 40 secondary schools in Cape Town, South Africa. SKILLZ is an evidence-based program previously implemented in similar contexts. Attendance in this study was suboptimal (less than 50%) despite qualitative indications of high acceptability and extensive efforts to adapt implementation and boost attendance. Qualitative and quantitative data gathered during anonymous surveys, in-depth interviews, and focus group discussions with participants with high and low attendance records, near-peer coaches, and school staff from both cohorts indicated that poor attendance could be attributed to several factors. Program adaptations, such as delivering difficult-to-access health services before participants attended the SKILLZ program rather than after, may have reduced the incentive for young people to attend the program. Practical barriers to attendance were identified, including security concerns, competing priorities, and unfamiliarity with after-school programming culture in this setting. Community engagement and acceptability of sexual education programs for adolescents alone may be insufficient to ensure program uptake and engagement.


Subject(s)
Sex Education , Sexual Behavior , Female , Humans , Adolescent , South Africa , Schools , Health Promotion
4.
Am J Hosp Palliat Care ; : 10499091231199722, 2023 Aug 31.
Article in English | MEDLINE | ID: mdl-37651687

ABSTRACT

Introduction: The hospice-in-place program at Vanderbilt University Medical Center (VUMC) is available to patients and families who elect for hospice benefits and are too unstable to be transported for hospice care. The goal of this study was to assess the satisfaction of family members of patients who died while hospitalized at VUMC and received hospice-in-place compared to the families of patients who did not receive hospice care. Methods: Next-of-kin satisfaction was measured through the administration of qualitative interviews and quantitative questionnaires. Semi-structured interviews were audio-recorded, and transcripts were analyzed using an iterative inductive-deductive approach to develop a conceptual framework. Participants were also asked to respond to a 10-question satisfaction questionnaire. Results: Forty participants were enrolled: 20 next-of-kin of patients who received hospice-in-place and 20 next-of-kin of patients who passed without hospice. Factors influencing satisfaction were organized into a conceptual framework with three categories: individual-level factors, systems-level factors, and modifying factors. For the questionnaires, the hospice-in-place group had a mean satisfaction score of 4.54 (0.76) out of five, while the non-hospice group had a mean score of 4.14 (1.00). A comparison of the two groups' responses did not show a statistically significant difference (P = 0.06). Discussion: Quantitative findings of this study showed improved satisfaction but were unable to show a significant difference in satisfaction with hospice-in-place compared to traditional care. Questionnaire results suggest that both types of care yield high satisfaction scores and are successfully supporting patients and families. The conceptual framework also adds to the understanding of end-of-life experiences at VUMC.

5.
Nutrients ; 15(1)2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36615865

ABSTRACT

Salt ingestion by animals and humans has been noted from prehistory. The search for salt is largely driven by a physiological need for sodium. There is a large body of literature on sodium intake in laboratory rats, but the vast majority of this work has used male rats. The limited work conducted in both male and female rats, however, reveals sex differences in sodium intake. Importantly, while humans ingest salt every day, with every meal and with many foods, we do not know how many of these findings from rodent studies can be generalized to men and women. This review provides a synthesis of the literature that examines sex differences in sodium intake and highlights open questions. Sodium serves many important physiological functions and is inextricably linked to the maintenance of body fluid homeostasis. Indeed, from a motivated behavior perspective, the drive to consume sodium has largely been studied in conjunction with the study of thirst. This review will describe the neuroendocrine controls of fluid balance, mechanisms underlying sex differences, sex differences in sodium intake, changes in sodium intake during pregnancy, and the possible neuronal mechanisms underlying these differences in behavior. Having reviewed the mechanisms that can only be studied in animal experiments, we address sex differences in human dietary sodium intake in reproduction, and with age.


Subject(s)
Appetite , Sodium, Dietary , Pregnancy , Humans , Female , Male , Rats , Animals , Appetite/physiology , Sex Characteristics , Sodium Chloride, Dietary , Sodium Chloride , Sodium , Thirst/physiology , Models, Animal
6.
J Commun Disord ; 101: 106295, 2023.
Article in English | MEDLINE | ID: mdl-36603411

ABSTRACT

INTRODUCTION: Online support group experiences, using social networking websites like Facebook, have shown much promise in past research unrelated to stuttering. Therefore, this study aimed to determine the utility of a Facebook-based stuttering support group that was created as an extension of and supplement to an in-person stuttering support group as a means of providing psychosocial support for people who stutter (PWS). METHOD: A qualitative approach that was inspired by ethnography was used to explore the experiences of seven participants (six participants who stutter and one participant who does not stutter) who digitally connect on a private Facebook-based stuttering support group that was created as an extension of and supplement to an already existing in-person stuttering support group. The main question posed to the participants related to describing their experiences being a member of the Facebook-based stuttering support group. RESULTS: Data analysis revealed two major themes, which included the benefits and challenges of participating in a Facebook-based stuttering support group.  Each major theme contained five subthemes. Specific results are discussed with reference to past research, as well as implications for practice and recommendations for future research. CONCLUSIONS: There are numerous benefits and challenges associated with being a member of a Facebook-based stuttering support group.  However, the overall utility of a Facebook-based stuttering support group, used in tandem with an in-person stuttering support experience, seems to provide members with a useful and impactful way to gain psychosocial support from other PWS.


Subject(s)
Self-Help Groups , Social Media , Stuttering , Humans , Social Group , Stuttering/psychology
7.
Physiol Behav ; 262: 114093, 2023 04 01.
Article in English | MEDLINE | ID: mdl-36706972

ABSTRACT

Eating and drinking co-occur and many of the same mechanisms that control one are involved in the control of the other, making it difficult to isolate specific mechanisms for the control of fluid intake. Glucagon-like peptide-1 (GLP-1) is a peptide that seems to be involved in the endogenous control of both ingestive behaviors, but we lack a thorough understanding of how and where GLP-1 is acting to control fluid intake. Vasopressin-deficient Brattleboro rats are a model of hereditary hypothalamic diabetes insipidus that have been used extensively for the study of vasopressin actions in behavior and physiology. Here, we propose that these rats, that eat normally but drink excessively, provide a useful model to dissociate central controls of food and fluid intakes. As an initial step toward establishing this model for these purposes, we focused on GLP-1. Similar to the effect observed after treatment with a GLP-1 receptor (GLP-1R) agonist, the intake difference between wildtype and Brattleboro rats was largely a function in the number of licking bursts, indicating differences in post-ingestive feedback (e.g., satiation). When given central injections of a GLP-1R agonist, the effect on feeding was comparable between wildtype and Brattleboro rats, but the effect of drug on fluid intake was markedly exaggerated in Brattleboro rats. Additionally, Brattleboro rats did not respond to GLP-1R antagonism, whereas wildtype rats did. Taken together, these results suggest that Brattleboro rats exhibit a selective disruption to GLP-1's control of water intake. Overall, these experiments provide foundational studies of the ingestive behavior of Brattleboro rats and demonstrate the potential to use these rats to disentangle the effects of GLP-1 on food and fluid intakes.


Subject(s)
Feeding Behavior , Glucagon-Like Peptide 1 , Rats , Animals , Glucagon-Like Peptide 1/pharmacology , Rats, Brattleboro , Feeding Behavior/physiology , Eating/physiology , Vasopressins/pharmacology , Glucagon-Like Peptide-1 Receptor/genetics
8.
Lang Speech Hear Serv Sch ; 54(1): 82-95, 2023 01 17.
Article in English | MEDLINE | ID: mdl-36417770

ABSTRACT

PURPOSE: Speech-language pathologists are influential in shaping identity development for individuals who stutter, particularly as it relates to communication. This study investigated the experiences of lesbian, gay, and bisexual individuals who stutter to learn more about how multiple marginalized identities affect their psychosocial experiences. METHOD: Semi-structured interviews were conducted with seven individuals who stutter with lesbian, gay, and bisexual identities. Participants ranged in age from 22 to 60 years. Data were analyzed for themes and categories by using interpretive phenomenological analysis. RESULTS: Four primary themes were identified: (a) the importance of visibility and shared social identity connections for affirmation; (b) effects of oppressive social expectations on identity; (c) intersectionality of stuttering, gay, lesbian, and bisexual identities; and (d) effects of not being affirmed for identity. DISCUSSION: Results are discussed in the context of identity affirmation and intersectionality. Through an understanding of identity formation and psychosocial experiences of lesbian, gay, and bisexual individuals who stutter, speech-language pathologists can use identity-affirmative practices to support individuals who stutter and mitigate stigmatizing experiences. Implications focus on suggestions for the provision of identity-affirming speech-language pathology practices for students who stutter.


Subject(s)
Sexual and Gender Minorities , Stuttering , Female , Humans , Young Adult , Adult , Middle Aged , Intersectional Framework , Stuttering/psychology
9.
Physiol Behav ; 247: 113707, 2022 04 01.
Article in English | MEDLINE | ID: mdl-35063424

ABSTRACT

The lateral hypothalamic area (LHA) is essential for ingestive behavior but has primarily been studied in modulating feeding, with comparatively scant attention on drinking. This is partly because most LHA neurons simultaneously promote feeding and drinking, suggesting that ingestive behaviors track together. A notable exception are LHA neurons expressing neurotensin (LHANts neurons): activating these neurons promotes water intake but modestly restrains feeding. Here we investigated the connectivity of LHANts neurons, their necessity and sufficiency for drinking and feeding, and how timing and resource availability influence their modulation of these behaviors. LHANts neurons project broadly throughout the brain, including to the lateral preoptic area (LPO), a brain region implicated in modulating drinking behavior. LHANts neurons also receive inputs from brain regions implicated in sensing hydration and energy status. While activation of LHANts neurons is not required to maintain homeostatic water or food intake, it selectively promotes drinking during the light cycle, when ingestive drive is low. Activating LHANts neurons during this period also increases willingness to work for water or palatable fluids, regardless of their caloric content. By contrast, LHANts neuronal activation during the dark cycle does not promote drinking, but suppresses feeding during this time. Finally, we demonstrate that the activation of the LHANts â†’ LPO projection is sufficient to mediate drinking behavior, but does not suppress feeding as observed after generally activating all LHANts neurons. Overall, our work suggests how and when LHANts neurons oppositely modulate ingestive behaviors.


Subject(s)
Hypothalamic Area, Lateral , Neurotensin , Food , Hypothalamic Area, Lateral/metabolism , Neurons/metabolism , Neurotensin/metabolism , Water
10.
Physiol Behav ; 236: 113418, 2021 07 01.
Article in English | MEDLINE | ID: mdl-33838203

ABSTRACT

Maintaining fluid balance is critical for life. The central components that control fluid intake are only partly understood. This contribution to the collection of papers highlighting work by members of the Society for the Study of Ingestive Behavior focuses on the role that dopamine has on fluid intake and describes the roles that various bioregulators can have on thirst and sodium appetite by influencing dopamine systems in the brain. The goal of the review is to highlight areas in need of more research and to propose a framework to guide that research. We hope that this framework will inspire researchers in the field to investigate these interesting questions in order to form a more complete understanding of how fluid intake is controlled.


Subject(s)
Dopamine , Sodium, Dietary , Angiotensin II , Appetite , Drinking , Thirst , Water-Electrolyte Balance
11.
Physiol Behav ; 221: 112910, 2020 07 01.
Article in English | MEDLINE | ID: mdl-32283107

ABSTRACT

Rats that are maintained on a high-fat diet (HFD) differ from controls in many ways, but how HFD maintenance affects water intake and drinking behavior has not been well studied. This is unfortunate because diet and obesity may influence fluid balance in humans through a mechanism that is poorly understood. We therefore tested the hypothesis that HFD maintenance affects water intake in rats. Water intake and drinking behavior are, in part, controlled by the actions of glucagon-like peptide-1 (GLP-1), a peptide which is well studied for its hypophagic effects. Previous studies have shown that HFD maintenance impairs the ability of GLP-1 receptor agonists to suppress food intake when the drug is administered peripherally, but not centrally. The effects of GLP-1 on fluid intake are thought to rely more on central receptor activation; therefore, a secondary aim of these experiments was to shed additional light on the location of GLP-1 responsive cells that mediate feeding vs drinking behavior. We maintained male Sprague-Dawley rats on HFD or low-fat diet (LFD) for six weeks and measured body weight, food intake, water intake, and drinking behavior. We then tested the relative contributions of diet and body weight on food intake and water intake after peripheral and central injections of GLP-1 receptor agonist Exendin-4 (Ex4). We found that HFD maintenance reduced the amount of water consumed, when intake was corrected for body weight. Consistent with other reports, rats on HFD showed a smaller suppression of food intake when given Ex4 peripherally, but not centrally. Water intake suppression when given Ex4 did not differ by diet or body weight regardless of injection site, however, adding support to the hypothesis that only central GLP-1 receptors are involved in water intake.


Subject(s)
Glucagon-Like Peptide-1 Receptor , Pharmaceutical Preparations , Animals , Diet, High-Fat/adverse effects , Eating , Glucagon-Like Peptide 1 , Male , Rats , Rats, Sprague-Dawley
12.
Appetite ; 149: 104616, 2020 06 01.
Article in English | MEDLINE | ID: mdl-32006660

ABSTRACT

Proper fluid balance is critical for life. Learning plays an important role in shaping the appetitive behaviors required for drinking. Children often forego drinking plain water and instead consume beverages such as milk or juice. What effect this may have on adult thirst responses remains an open question. To model aspects of the human condition, we bred Sprague-Dawley rats and prevented the pups from obtaining fluid other than from nursing. Pups were weaned onto either tap water, 5% sucrose, or 0.45% saline, and given access to only that fluid for at least 7 weeks. We then measured intake of water or sucrose/saline in one-bottle tests after mild hypertonic saline (HS) injection, or overnight fluid deprivation, and in two-bottle tests after HS injection while rats were maintained on their respective fluids, and after all subjects had only water to drink for a week. We found that sucrose- and saline-maintained rats drank less water than did controls after the HS challenge. After overnight fluid deprivation, rats maintained on saline drank less water and more saline, but there was no difference in intake between water-maintained and sucrose-maintained rats. Differences in licking patterns, including more licks/burst for sucrose by sucrose-maintained rats were detected, even in cases when total intake was not different. These data provide evidence that adult rat water intake can be reduced by exclusively drinking sucrose or saline early in life.


Subject(s)
Drinking Behavior/physiology , Drinking Water/analysis , Drinking/physiology , Saline Solution, Hypertonic/administration & dosage , Sucrose/administration & dosage , Animals , Rats , Rats, Sprague-Dawley , Water-Electrolyte Balance/physiology , Weaning
13.
Physiol Behav ; 215: 112775, 2020 03 01.
Article in English | MEDLINE | ID: mdl-31843472

ABSTRACT

The pedunculopontine tegmentum (PPTg) plays a role in processing multiple sensory inputs and innervates brain regions associated with reward-related behaviors. The urotensin II receptor, activated by the urotensin II peptide (UII), is selectively expressed by the cholinergic neurons of the PPTg. Although the exact function of cholinergic neurons of the PPTg is unknown, they are thought to contribute to the perception of reward magnitude or salience detection. We hypothesized that the activation of PPTg cholinergic neurons would alter sensory processing across multiple modalities (ex. taste and hearing). Here we had three aims: first, determine if cholinergic activation is involved in consumption behavior of palatable solutions (sucrose). Second, if so, distinguish the impact of the caloric value by using saccharin, a zero calorie sweetener. Lastly, we tested the UII-mediated effects on perception of acoustic stimuli by measuring acoustic startle reflex (ASR). Male Sprague-Dawley rats were bilaterally cannulated into the PPTg, then placed under food restriction lasting the entire consumption experiment (water ad lib.). Treatment consisted of a microinjection of either 1 µL of aCSF or 1 µL of 10 µM UII into the PPTg, and the rats were immediately given access to either sucrose or saccharin. For the remaining five days, rats were allowed one hour access per day to the same sweet solution without any further treatments. During the saccharin experiment rats were tested in a contact lickometer which recorded each individual lick to give insight into the microstructure of the consumption behavior. ASR testing consisted of a baseline (no treatment), treatment day, and two additional days (no treatment). Immediately following the microinjection of UII, consumption of both saccharin and sucrose increased compared to controls. This significant increase persisted for days after the single administration of UII, but there was no generalized arousal or increase in water consumption between testing sessions. The effects on ASR were not significant. Activating cholinergic PPTg neurons may lead to a miscalculation of the salience of external stimuli, implicating the importance of cholinergic input in modulating a variety of behaviors. The long-lasting effects seen after UII treatment support further research into the role of sensory processing on reward related-behaviors at the level of the PPTg cholinergic neurons.


Subject(s)
Feeding Behavior/drug effects , Pedunculopontine Tegmental Nucleus , Sweetening Agents/pharmacology , Urotensins/pharmacology , Acoustic Stimulation , Animals , Male , Microinjections , Parasympathetic Nervous System/drug effects , Rats , Rats, Sprague-Dawley , Reflex, Startle/drug effects , Reward , Saccharin/pharmacology , Sucrose/pharmacology , Taste/drug effects , Urotensins/administration & dosage
14.
Endocrine ; 66(2): 349-359, 2019 11.
Article in English | MEDLINE | ID: mdl-31020463

ABSTRACT

PURPOSE: To study the ability of a novel bovine serum albumin-angiotensin II (BSA-Ang II) conjugate to effect responses of the AT1 angiotensin II receptor subtype mediated by the G-protein-coupled and the beta-arrestin pathways. METHODS: Angiotensin II (Ang II) was conjugated with bovine serum albumin and compared with Ang II for competition binding to AT1 receptors, to stimulate aldosterone release from adrenocortical cells, to promote beta-arrestin binding to AT1 receptors, to promote calcium mobilization, and stimulate drinking of water and saline by rats. RESULTS: The BSA-Ang II conjugate was less potent competing for AT1R binding, but was equally efficacious at stimulating aldosterone release from H295R adrenocortical cells. Both BSA-Ang II and Ang II stimulated calcium mobilization and beta-arrestin binding to AT1 receptors. BSA-Ang II and Ang II stimulated water appetite equivalently but BSA-Ang II stimulated saline appetite more than Ang II. Both BSA-Ang II and Ang II were considerably more potent at causing calcium mobilization than ß-arrestin binding. CONCLUSIONS: Addition of a high molecular weight molecule to Ang II reduced its AT1 receptor binding affinity, but did not significantly alter stimulation of aldosterone release or water consumption. The BSA-Ang II conjugate caused a greater saline appetite than Ang II suggesting that it may be a more efficacious agonist of this beta-arrestin-mediated response than Ang II. The higher potency calcium signaling response suggests that the G-protein-coupled responses predominate at physiological concentrations of Ang II, while the beta-arrestin response requires pathophysiological or pharmacological concentrations of Ang II to occur.


Subject(s)
Adrenal Cortex/drug effects , Angiotensin II/pharmacology , Serum Albumin, Bovine/pharmacology , Signal Transduction/drug effects , beta-Arrestins/metabolism , Adrenal Cortex/metabolism , Aldosterone/metabolism , Animals , Calcium Signaling/drug effects , Cell Line, Tumor , Drinking/drug effects , Humans , Liver/drug effects , Liver/metabolism , Male , Rats , Rats, Sprague-Dawley , Receptor, Angiotensin, Type 1/metabolism
15.
Horm Behav ; 107: 20-25, 2019 01.
Article in English | MEDLINE | ID: mdl-30462987

ABSTRACT

Activation of membrane-associated estrogen receptors (mER) decreases food and water intake in female rats. Additional studies suggest these effects are mediated, at least in part, by membrane-associated estrogen receptor alpha (ERα). Nevertheless, the critical site of action and the intracellular signaling required for the ingestive effects of ERα remain unclear. Estradiol given to the medial preoptic area (mPOA) decreases ingestive behaviors, and membrane-associated ERα has been shown to affect intracellular signaling through interactions with metabotropic glutamate receptor (mGluR) subtypes, but an involvement of this signaling pathway, in the mPOA, in ingestive behavior remains untested. To address these open questions, we first showed that activation of mER in the mPOA decreased both overnight food and water intake, and did so in a time course consistent with a genomic mechanism of action. Next, we tested the requirement of mGluR1a signaling in the mPOA for the anorexigenic and anti-dipsogenic effects of estradiol. As expected, estradiol in the mPOA decreased food intake, but only in the absence of an mGluR1a antagonist. The same was not true for estradiol effects on water intake, which were unaffected by an mGluR1a antagonist. These results suggest that estrogens require mGluR activation for at least some of their effects on ingestive behaviors, and indicate that the mPOA is a critical site of action. The results also reveal an interesting divergence in the estrogenic control of ingestive behavior by which mGluR signaling in the mPOA plays a role in the control of food intake, but not water intake.


Subject(s)
Anorexia/chemically induced , Appetite Depressants/pharmacology , Estradiol/pharmacology , Preoptic Area/drug effects , Receptors, Estradiol/metabolism , Receptors, Metabotropic Glutamate/metabolism , Animals , Anorexia/metabolism , Drinking/drug effects , Eating/drug effects , Female , Preoptic Area/metabolism , Rats , Rats, Long-Evans , Signal Transduction/drug effects
18.
Endocrinology ; 159(2): 676-684, 2018 02 01.
Article in English | MEDLINE | ID: mdl-29186291

ABSTRACT

Previous in vivo and in vitro studies demonstrate that the angiotensin type 1 receptor rapidly desensitizes after exposure to angiotensin II (AngII). Behaviorally, this likely underlies the reduced drinking observed after acute repeated central injections of AngII. To date, this phenomenon has been studied exclusively in male subjects. Because there are sex differences in the dipsogenic potency of AngII, we hypothesized that sex differences also exist in desensitization caused by AngII. As expected, when male rats were pretreated with AngII, they drank less water after a test injection of AngII than did rats pretreated with vehicle. Intact cycling female rats, however, drank similar amounts of water after AngII regardless of the pretreatment. To probe the mechanism underlying this sex difference, we tested the role of gonadal hormones in adult and developing rats. Gonadectomy in adults did not produce a male-like propensity for desensitization of water intake in female rats, nor did it produce a female-like response in male rats. To test if neonatal brain masculinization generated a male-like responsiveness, female pups were treated at birth with vehicle, testosterone propionate (TP), or dihydrotestosterone (DHT). When tested as adults, TP-treated female rats showed a male-like desensitization after repeated AngII that was not found in vehicle- or DHT-treated rats. Together, these data reveal a striking sex difference in the behavioral response to elevated AngII that is mediated by organizational effects of gonadal hormones and provide an example of one of the many ways that sex influences the renin-angiotensin-aldosterone system.


Subject(s)
Angiotensin II/administration & dosage , Drinking/drug effects , Water/metabolism , Animals , Female , Male , Rats , Rats, Sprague-Dawley , Renin-Angiotensin System/drug effects , Sex Factors
19.
Physiol Behav ; 179: 340-345, 2017 Oct 01.
Article in English | MEDLINE | ID: mdl-28687177

ABSTRACT

Daily injections of angiotensin II (AngII) cause a progressive increase of water intake that resembles a classically ascribed non-associative sensitization. Consistent with the presumption that the observed increase in intake was sensitization, we hypothesized that it resulted from a pharmacological interaction between AngII and its receptor. To test this hypothesis, and remove the influence of drinking itself, we implemented a delay in water access after injection of AngII (icv) on four consecutive 'induction days,' and then measured intake on the next day ('test day') when rats were allowed to drink immediately after AngII. The delay in water access effectively reduced water intake on the four induction days, and rats with longer delays in access drank less on the test day than did rats allowed to drink immediately after AngII on the induction days. Additional experiments ruled out a role for a conditioned drinking response to the injection alone, and demonstrated a lack of conditioned appetition after pairing injections of AngII with water given by intragastric catheter. Taken together, these findings suggest that the increased drinking observed after daily injections of AngII is a conditioned appetition after repeated pairings of AngII and water intake. We further conclude that repeated stimulation of the AngII receptor alone is not sufficient to drive appetition.


Subject(s)
Angiotensin II/pharmacology , Association Learning/drug effects , Drinking Behavior/drug effects , Drinking/drug effects , Vasoconstrictor Agents/pharmacology , Analysis of Variance , Animals , Drinking Water , Male , Rats, Sprague-Dawley , Thirst/drug effects , Time Factors
20.
Horm Behav ; 93: 128-136, 2017 07.
Article in English | MEDLINE | ID: mdl-28571936

ABSTRACT

Sex differences in fluid intake stimulated by angiotensin II (AngII) have been reported, but the direction of the differences is inconsistent. To resolve these discrepancies, we measured water intake by male and female rats given AngII. Males drank more than females, but when intake was normalized to body weight, the sex difference was reversed. Weight-matched males and females, however, had no difference in intake. Using a linear mixed model analysis, we found that intake was influenced by weight, sex, and AngII dose. We used linear regression to disentangle these effects further. Comparison of regression coefficients revealed sex and weight differences at high doses of AngII. Specifically, after 100ng AngII, weight was a predictor of intake in males, but not in females. Next, we tested for differences in AngII-induced intake in male and females allowed to drink both water and saline. Again, males drank more water than females, but females showed a stronger preference for saline. Drinking microstructure analysis suggested that these differences were mediated by postingestive signals and more bottle switches by the females. Finally, we probed for differences in the expression of components of the renin-angiotensin system in the brains of males and females and found sex differences in several genes in discrete brain regions. These results provide new information to help understand key sex differences in ingestive behaviors, and highlight the need for additional research to understand baseline sex differences, particularly in light of the new NIH initiative to balance sex in biomedical research.


Subject(s)
Angiotensin II/pharmacology , Body Weight/drug effects , Drinking/drug effects , Sex Characteristics , Animals , Blood Pressure/drug effects , Brain/drug effects , Brain/metabolism , Female , Male , Rats , Rats, Sprague-Dawley , Water-Electrolyte Balance/drug effects
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