Multisectoral interventions for urban health in Africa: a mixed-methods systematic review.

Increasing evidence suggests that urban health objectives are best achieved through a multisectoral approach. This approach requires multiple sectors to consider health and well-being as a central aspect of their policy development and implementation, recognising that numerous determinants of health lie outside (or beyond the confines of) the health sector. However, collaboration across sectors remains scarce and multisectoral interventions to support health are lacking in Africa. To address this gap in research, we conducted a mixed-method systematic review of multisectoral interventions aimed at enhancing health, with a particular focus on non-communicable diseases in urban African settings. Africa is the world's fastest urbanising region, making it a critical context in which to examine the impact of multisectoral approaches to improve health. This systematic review provides a valuable overview of current knowledge on multisectoral urban health interventions and enables the identification of existing knowledge gaps, and consequently, avenues for future research. We searched four academic databases (PubMed, Scopus, Web of Science, Global Health) for evidence dated 1989-2019 and identified grey literature from expert input. We identified 53 articles (17 quantitative, 20 qualitative, 12 mixed methods) involving collaborations across 22 sectors and 16 African countries. The principle guiding the majority of the multisectoral interventions was community health equity (39.6%), followed by healthy cities and healthy urban governance principles (32.1%). Targeted health outcomes were diverse, spanning behaviour, environmental and active participation from communities. With only 2% of all studies focusing on health equity as an outcome and with 47% of studies published by first authors located outside Africa, this review underlines the need for future research to prioritise equity both in terms of research outcomes and processes. A synthesised framework of seven interconnected components showcases an ecosystem on multisectoral interventions for urban health that can be examined in the future research in African urban settings that can benefit the health of people and the planet.Paper ContextMain findings: Multisectoral interventions were identified in 27.8% of African countries in the African Union, targeted at major cities with five sectors present at all intervention stages: academia or research, agriculture, government, health, and non-governmental.Added knowledge: We propose a synthesised framework showcasing an ecosystem on multisectoral interventions for urban health that can guide future research in African urban settings.Global health impact for policy and action: This study reveals a crucial gap in evidence on evaluating the long-term impact of multisectoral interventions and calls for partnerships involving various sectors and robust community engagement to effectively deliver and sustain health-promoting policies and actions.

Two Sides of the Same Virtual Coin: Investigating Psychosocial Effects of Video Game Play, including Stress Relief Motivations as a Gateway to Problematic Video Game Usage.

Video gamers can play to negate the psychological impact of stress, which may become problematic when users over-rely on the stress relief potential of gaming. This study used a repeated measures experimental design to investigate the relationships between stress, video gaming, and problematic video gaming behaviours in a convenience sample of 40 students at a UK university. The results indicated that positive affect increased and negative affect decreased, whilst a biological stress measure (instantaneous pulse rate) also decreased after a short video gaming session (t(36) = 4.82, p < 0.001, d = 0.79). The results also suggested that video gaming can act as a short-term buffer against the physiological impact of stress. Further research should focus on testing individuals who have been tested for gaming disorder, as opposed to the general population. Research could also utilise variations of the methodological framework used in this study to examine the intensity of a stress relief effect under different social situations. The study's findings in relation to published works are also discussed.

Phase 1 trial of TPI 287, a microtubule stabilizing agent, in combination with bevacizumab in adults with recurrent glioblastoma.

Background: Recurrent glioblastoma (rGBM) has limited treatment options. This phase 1 protocol was designed to study the safety and preliminary efficacy of TPI 287, a central nervous system penetrant microtubule stabilizer, in combination with bevacizumab (BEV) for the treatment of rGBM. Methods: GBM patients with up to 2 prior relapses without prior exposure to anti-angiogenic therapy were eligible. A standard 3 + 3 design was utilized to determine the maximum tolerated dose (MTD) of TPI 287. Cohorts received TPI 287 at 140-220 mg/m2 every 3 weeks and BEV 10 mg/kg every 2 weeks during 6-week cycles. An MRI was performed after each cycle, and treatment continued until progression as determined via response assessment in neuro-oncology criteria. Results: Twenty-four patients were enrolled at 6 centers. Treatment was generally well tolerated. Fatigue, myelosuppression, and peripheral neuropathy were the most common treatment emergent adverse events. Dose-limiting toxicity was not observed, thus the MTD was not determined. Twenty-three patients were evaluable for median and 6-month progression-free survival, which were 5.5 months (mo) and 40%, respectively. Median and 12-month overall survival were 13.4 mo and 64%, respectively. The optimal phase 2 dose was determined to be 200 mg/m2. Conclusions: TPI 287 can be safely combined with BEV for the treatment of rGBM and preliminary efficacy supports further investigation of this combination.

Chronic intermittent hypoxia-induced hypertension: the impact of sex hormones.

Obstructive sleep apnea, a common form of sleep-disordered breathing, is characterized by intermittent cessations of breathing that reduce blood oxygen levels and contribute to the development of hypertension. Hypertension is a major complication of obstructive sleep apnea that elevates the risk of end-organ damage. Premenopausal women have a lower prevalence of obstructive sleep apnea and cardiovascular disease than men and postmenopausal women, suggesting that sex hormones play a role in the pathophysiology of sleep apnea-related hypertension. The lack of protection in men and postmenopausal women implicates estrogen and progesterone as protective agents but testosterone as a permissive agent in sleep apnea-induced hypertension. A better understanding of how sex hormones contribute to the pathophysiology of sleep apnea-induced hypertension is important for future research and possible hormone-based interventions. The effect of sex on the pathophysiology of sleep apnea and associated intermittent hypoxia-induced hypertension is of important consideration in the screening, diagnosis, and treatment of the disease and its cardiovascular complications. This review summarizes our current understanding of the impact of sex hormones on blood pressure regulation in sleep apnea with a focus on sex differences.

Effects of bile duct ligation on the inhibitory control of supraoptic vasopressin neurons.

Dilutional hyponatremia due to increased plasma arginine vasopressin (AVP) is associated with liver cirrhosis. However, plasma AVP remains elevated despite progressive hypoosmolality. This study investigated changes to inhibitory control of supraoptic nucleus (SON) AVP neurons during liver cirrhosis. Experiments were conducted with adult male Sprague-Dawley rats. Bile duct ligation was used as a model of chronic liver cirrhosis. An adeno-associated virus containing a construct with an AVP promoter and either green fluorescent protein (GFP) or a ratiometric chloride indicator, ClopHensorN, was bilaterally injected into the SON of rats. After 2 weeks, rats received either BDL or sham surgery, and liver cirrhosis was allowed to develop for 4 weeks. In vitro, loose patch recordings of action potentials were obtained from GFP-labeled and unlabeled SON neurons in response to a brief focal application of the GABAA agonist muscimol (100 µM). Changes to intracellular chloride ([Cl]i) following muscimol application were determined by changes to the fluorescence ratio of ClopHensorN. The contribution of cation chloride cotransporters NKCC1 and KCC2 to changes in intracellular chloride was investigated using their respective antagonists, bumetanide (BU, 10 µM) and VU0240551 (10 µM). Plasma osmolality and hematocrit were measured as a marker of dilutional hyponatremia. The results showed reduced or absent GABAA -mediated inhibition in a greater proportion of AVP neurons from BDL rats as compared to sham rats (100% inhibition in sham vs. 47% in BDL, p = .001). Muscimol application was associated with increased [Cl]i in most cells from BDL as compared to cells from sham rats (χ2 = 30.24, p < .001). NKCC1 contributed to the impaired inhibition observed in BDL rats (p < .001 BDL - BU vs. BDL + BU). The results show that impaired inhibition of SON AVP neurons and increased intracellular chloride contribute to the sustained dilutional hyponatremia in liver cirrhosis.

Chronic intermittent hypoxia enhances glycinergic inhibition in nucleus tractus solitarius.

Chronic intermittent hypoxia (CIH), an animal model of sleep apnea, has been shown to alter the activity of second-order chemoreceptor neurons in the caudal nucleus of the solitary tract (cNTS). Although numerous studies have focused on excitatory plasticity, few studies have explored CIH-induced plasticity impacting inhibitory inputs to NTS neurons, and the roles of GABAergic and glycinergic inputs on heightened cNTS excitability following CIH are unknown. In addition, changes in astrocyte function may play a role in cNTS plasticity responses to CIH. This study tested the effects of a 7-day CIH protocol on miniature inhibitory postsynaptic currents (mIPSCs) in cNTS neurons receiving chemoreceptor afferents. Normoxia-treated rats primarily displayed GABA mIPSCs, whereas CIH-treated rats exhibited a shift toward combined GABA/glycine-mediated mIPSCs. CIH increased glycinergic mIPSC amplitude and area. This shift was not observed in dorsal motor nucleus of the vagus neurons or cNTS cells from females. Immunohistochemistry showed that strengthened glycinergic mIPSCs were associated with increased glycine receptor protein and were dependent on receptor trafficking in CIH-treated rats. In addition, CIH altered astrocyte morphology in the cNTS, and inactivation of astrocytes following CIH reduced glycine receptor-mediated mIPSC frequency and overall mIPSC amplitude. In cNTS, CIH produced changes in glycine signaling that appear to reflect increased trafficking of glycine receptors to the cell membrane. Increased glycine signaling in cNTS associated with CIH also appears to be dependent on astrocytes. Additional studies will be needed to determine how CIH influences glycine receptor expression and astrocyte function in cNTS.NEW & NOTEWORTHY Chronic intermittent hypoxia (CIH) has been used to mimic the hypoxemia associated with sleep apnea and determine how these hypoxemias influence neural function. The nucleus of the solitary tract is the main site for chemoreceptor input to the CNS, but how CIH influences NTS inhibition has not been determined. These studies show that CIH increases glycine-mediated miniature IPSCs through mechanisms that depend on protein trafficking and astrocyte activation.

Rethinking fast and slow processing in autism.

Following the popularity of dual process models in social and cognitive psychology, there is major interest in the possibility that autism is associated with impaired "fast" intuitive thinking but enhanced "slow" or "rational" deliberative thinking. If correct, this has great potential to help understand various strengths and difficulties characteristic of autism. Previous empirical investigations of this phenomenon, however, are marred by concerns about the measurement of intuitive and deliberative processing, as well as broader problems in clinical psychological science (e.g., small underpowered studies, lack of replication). Making a step change, we conducted four large-scale studies to examine dual processing in autism, including a preregistered comparison of 200 autistic and nonautistic adults. Participants completed contemporary cognitive and self-report measures of intuitive and deliberative processing, as well as a psychometrically robust measure of general cognitive ability. Except for lower self-reported intuitive thinking, we found no unique contributions of autism to intuitive or deliberative thinking across all four studies, as evidenced by frequentist and Bayesian analyses. Overall, these studies indicate that intuitive and deliberative thinking is neither enhanced nor particularly impaired in relation to autism. We deliberate on the implications of these findings for theories of autism and future investigation of strengths and difficulties in autistic people. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Neurodegenerative Disease: Roles for Sex, Hormones, and Oxidative Stress.

Neurodegenerative diseases cause severe impairments in cognitive and motor function. With an increasing aging population and the onset of these diseases between 50 and 70 years, the consequences are bound to be devastating. While age and longevity are the main risk factors for neurodegenerative diseases, sex is also an important risk factor. The characteristic of sex is multifaceted, encompassing sex chromosome complement, sex hormones (estrogens and androgens), and sex hormone receptors. Sex hormone receptors can induce various signaling cascades, ranging from genomic transcription to intracellular signaling pathways that are dependent on the health of the cell. Oxidative stress, associated with aging, can impact the health of the cell. Sex hormones can be neuroprotective under low oxidative stress conditions but not in high oxidative stress conditions. An understudied sex hormone receptor that can induce activation of oxidative stress signaling is the membrane androgen receptor (mAR). mAR can mediate nicotinamide adenine dinucleotide-phosphate (NADPH) oxidase (NOX)-generated oxidative stress that is associated with several neurodegenerative diseases, such as Alzheimer disease. Further complicating this is that aging can alter sex hormone signaling. Prior to menopause, women experience more estrogens than androgens. During menopause, this sex hormone profile switches in women due to the dramatic ovarian loss of 17ß-estradiol with maintained ovarian androgen (testosterone, androstenedione) production. Indeed, aging men have higher estrogens than aging women due to aromatization of androgens to estrogens. Therefore, higher activation of mAR-NOX signaling could occur in menopausal women compared with aged men, mediating the observed sex differences. Understanding of these signaling cascades could provide therapeutic targets for neurodegenerative diseases.

Redevelopment of the Predict: Breast Cancer website and recommendations for developing interfaces to support decision-making.

OBJECTIVES: To develop a new interface for the widely used prognostic breast cancer tool: Predict: Breast Cancer. To facilitate decision-making around post-surgery breast cancer treatments. To derive recommendations for communicating the outputs of prognostic models to patients and their clinicians. METHOD: We employed a user-centred design process comprised of background research and iterative testing of prototypes with clinicians and patients. Methods included surveys, focus groups and usability testing. RESULTS: The updated interface now caters to the needs of a wider audience through the addition of new visualisations, instantaneous updating of results, enhanced explanatory information and the addition of new predictors and outputs. A programme of future research was identified and is now underway, including the provision of quantitative data on the adverse effects of adjuvant breast cancer treatments. Based on our user-centred design process, we identify six recommendations for communicating the outputs of prognostic models including the need to contextualise statistics, identify and address gaps in knowledge, and the critical importance of engaging with prospective users when designing communications. CONCLUSIONS: For prognostic algorithms to fulfil their potential to assist with decision-making they need carefully designed interfaces. User-centred design puts patients and clinicians needs at the forefront, allowing them to derive the maximum benefit from prognostic models.

AT1a-dependent GABAA inhibition in the MnPO following chronic intermittent hypoxia.

Chronic intermittent hypoxia (CIH) is associated with diurnal hypertension, increased sympathetic nerve activity (SNA), and increases in circulating angiotensin II (ANG II). In rats, CIH increases angiotensin type 1 (AT1a) receptor expression in the median preoptic nucleus (MnPO), and pharmacological blockade or viral knockdown of this receptor prevents CIH-dependent increases in diurnal blood pressure. The current study investigates the role of AT1a receptor in modulating the activity of MnPO neurons following 7 days of CIH. Male Sprague-Dawley rats received MnPO injections of an adeno-associated virus with an shRNA against the AT1a receptor or a scrambled control. Rats were then exposed to CIH for 8 h a day for 7 days. In vitro, loose patch recordings of spontaneous action potential activity were made from labeled MnPO neurons in response to brief focal application of ANG II or the GABAA receptor agonist muscimol. In addition, MnPO K-Cl cotransporter isoform 2 (KCC2) protein expression was assessed using Western blot. CIH impaired the duration but not the magnitude of ANG II-mediated excitation in the MnPO. Both CIH and AT1a knockdown also impaired GABAA-mediated inhibition, and CIH with AT1a knockdown produced GABAA-mediated excitation. Recordings using the ratiometric Cl- indicator ClopHensorN showed CIH was associated with Cl- efflux in MnPO neurons that was associated with decreased KCC2 phosphorylation. The combination of CIH and AT1a knockdown attenuated reduced KCC2 phosphorylation seen with CIH alone. The current study shows that CIH, through the activity of AT1a receptors, can impair GABAA-mediated inhibition in the MnPO and contribute to sustained hypertension.

Cardiovascular Neuroendocrinology: Emerging Role for Neurohypophyseal Hormones in Pathophysiology.

Arginine vasopressin (AVP) and oxytocin (OXY) are released by magnocellular neurosecretory cells that project to the posterior pituitary. While AVP and OXY currently receive more attention for their contributions to affiliative behavior, this mini-review discusses their roles in cardiovascular function broadly defined to include indirect effects that influence cardiovascular function. The traditional view is that neither AVP nor OXY contributes to basal cardiovascular function, although some recent studies suggest that this position might be re-evaluated. More evidence indicates that adaptations and neuroplasticity of AVP and OXY neurons contribute to cardiovascular pathophysiology.

Role of angiotensin II in chronic intermittent hypoxia-induced hypertension and cognitive decline.

Sleep apnea is characterized by momentary interruptions in normal respiration and leads to periods of decreased oxygen, or intermittent hypoxia. Chronic intermittent hypoxia is a model of the hypoxemia associated with sleep apnea and results in a sustained hypertension that is maintained during normoxia. Adaptations of the carotid body and activation of the renin-angiotensin system may contribute to the development of hypertension associated with chronic intermittent hypoxia. The subsequent activation of the brain renin-angiotensin system may produce changes in sympathetic regulatory neural networks that support the maintenance of the hypertension associated with intermittent hypoxia. Hypertension and sleep apnea not only increase risk for cardiovascular disease but are also risk factors for cognitive decline and Alzheimer's disease. Activation of the angiotensin system could be a common mechanism that links these disorders.

The absolute and relative risk of type 2 diabetes after gestational diabetes: A systematic review and meta-analysis of 129 studies.

AIMS: To estimate development of type 2 diabetes (T2DM) in women with previous gestational diabetes (GDM) and investigate characteristics associated with higher diagnoses, building on previous meta-analyses and exploring heterogeneity. METHODS: Systematic literature review of studies published up to October 2019. We included studies reporting progression to T2DM ≥6 months after pregnancy, if diagnostic methods were reported and ≥50 women with GDM participated. We conducted random-effects meta-analyses and meta-regression of absolute and relative T2DM risk. PROSPERO ID: CRD42017080299. RESULTS: In 129 included studies, the percentage diagnosed with T2DM was 12% (95% confidence interval 8-16%) higher for each additional year after pregnancy, with a third developing diabetes within 15 years. Development was 18% (5-34%) higher per unit BMI at follow-up, and 57% (39-70%) lower in White European populations compared to others (adjusted for ethnicity and follow-up). Women with GDM had a relative risk of T2DM of 8.3 (6.5-10.6). 17.0% (15.1-19.0%) developed T2DM overall, although heterogeneity between studies was substantial (I2 99.3%), and remained high after accounting for various study-level characteristics. CONCLUSIONS: Percentage developing T2DM after GDM is highly variable. These findings highlight the need for sustained follow-up after GDM through screening, and interventions to reduce modifiable risk factors.

The delay-reward heuristic: What do people expect in intertemporal choice tasks?

Recent research has shown that risk and reward are positively correlated in many environments, and that people have internalized this association as a "risk-reward heuristic": when making choices based on incomplete information, people infer probabilities from payoffs and vice-versa, and these inferences shape their decisions. We extend this work by examining people's expectations about another fundamental trade-off-that between monetary reward and delay. In 2 experiments (total N = 670), we adapted a paradigm previously used to demonstrate the risk-reward heuristic. We presented participants with intertemporal choice tasks in which either the delayed reward or the length of the delay was obscured. Participants inferred larger rewards for longer stated delays, and longer delays for larger stated rewards; these inferences also predicted people's willingness to take the delayed option. In exploratory analyses, we found that older participants inferred longer delays and smaller rewards than did younger ones. All of these results replicated in 2 large-scale pre-registered studies with participants from a different population (total N = 2138). Our results suggest that people expect intertemporal choice tasks to offer a trade-off between delay and reward, and differ in their expectations about this trade-off. This "delay-reward heuristic" offers a new perspective on existing models of intertemporal choice and provides new insights into unexplained and systematic individual differences in the willingness to delay gratification.

Gq DREADD activation of CaMKIIa MnPO neurons stimulates nitric oxide activity.

Designer receptors exclusively activated by designer drugs (DREADDs) modify cellular activity following administration of the exogenous ligand clozapine-N-oxide (CNO). However, some reports indicate CNO may have off-target effects. The current studies investigate the use of Gq DREADDs in CaMKIIa-expressing neurons in the median preoptic nucleus (MnPO). Male Sprague-Dawley rats (250 g) anesthetized with isoflurane were stereotaxically microinjected in the MnPO with the Gq DREADD (AAV5-CaMKIIa-HM3D-mCherry) or control virus (AAV5-CaMKIIa-mCherry). Following a 2-wk recovery, rats were used for either immunohistochemical Fos analysis or in vitro patch-clamp electrophysiology. In Gq DREADD-injected rats, CNO induced significant increases in Fos staining in the MnPO and in regions that receive direct or indirect projections from the MnPO. In electrophysiological studies, CNO depolarized and augmented firing frequency in both Gq DREADD-positive neurons (Gq DREADD) as well as unlabeled MnPO neurons in slices from Gq DREADD-injected rats (Gq DREADDx). Gq DREADDx neurons also displayed increases in spontaneous postsynaptic current (sPSC) frequency in response to CNO. Additionally, CaMKIIa-positive MnPO neurons, which also express nitric oxide synthase (NOS), were treated with Nω-nitro-l-arginine (l-NNA; competitive inhibitor of NOS) and hemoglobin (NO scavenger) to assess the role of NO in Gq DREADDx neuron recruitment. Both l-NNA and hemoglobin blocked CNO-induced effects in Gq DREADDx neurons without affecting Gq DREADD neurons. These findings indicate that Gq DREADD-mediated activation of CaMKIIa/NOS expressing neurons in the MnPO can influence the activity of neighboring neurons. Future studies utilizing the use of Gq DREADDs will need to consider the potential recruitment of additional cell populations.NEW & NOTEWORTHY Rats were injected in the median preoptic nucleus (MnPO) with either an adeno-associated virus (AAV) and excitatory (Gq) designer receptor exclusively activated by designer drugs (DREADD) construct or a control AAV. In the Gq DREADD-injected rats only, clozapine-N-oxide (CNO) increased Fos staining in the MnPO and its targets and increased neuron action potential frequency. In electrophysiology experiments with slices with DREADD cells, unlabeled cells were activated and this was likely due to nitric oxide release by the DREADD cells.

Recommendations for designing genetic test reports to be understood by patients and non-specialists.

Patients and non-specialist healthcare professionals are increasingly expected to understand and interpret the results of genetic or genomic testing. These results are currently reported using a variety of templates, containing different amounts, levels, and layouts of information. We set out to establish a set of recommendations for communicating genetic test results to non-expert readers. We employed a qualitative-descriptive study design with user-centred design principles, including a mixture of in-person semi-structured interviews and online questionnaires with patients, healthcare professionals and the general public. The resulting recommendations and example template include providing at-a-glance comprehension of what the test results mean for the patient; suggested next steps; and details of further information and support. Separation and inclusion of technical methodological details enhances non-specialists' understanding, while retaining important information for specialists and the patients' records. The recommendations address the high-level needs of patients and their non-specialist clinicians when receiving genetic test results. These recommendations provide a solid foundation for the major content and structure of reports, and we recommend further engagement with patients and clinicians to tailor reports to specific types of test and results.

Sniffer cells for the detection of neural Angiotensin II in vitro.

Neuropeptide release in the brain has traditionally been difficult to observe. Existing methods lack temporal and spatial resolution that is consistent with the function and size of neurons. We use cultured "sniffer cells" to improve the temporal and spatial resolution of observing neuropeptide release. Sniffer cells were created by stably transfecting Chinese Hamster Ovary (CHO) cells with plasmids encoding the rat angiotensin type 1a receptor and a genetically encoded Ca2+ sensor. Isolated, cultured sniffer cells showed dose-dependent increases in fluorescence in response to exogenously applied angiotensin II and III, but not other common neurotransmitters. Sniffer cells placed on the median preoptic nucleus (a presumptive site of angiotensin release) displayed spontaneous activity and evoked responses to either electrical or optogenetic stimulation of the subfornical organ. Stable sniffer cell lines could be a viable method for detecting neuropeptide release in vitro, while still being able to distinguish differences in neuropeptide concentration.

Effects of salt-loading on supraoptic vasopressin neurones assessed by ClopHensorN chloride imaging.

Salt-loading (SL) impairs GABAA inhibition of arginine vasopressin (AVP) neurones in the supraoptic nucleus (SON) of the hypothalamus. Based on previous studies, we hypothesised that SL activates tyrosine receptor kinase B (TrkB), down-regulating the activity of K+ /Cl- co-transporter2 (KCC2) and up-regulating Na+ /K+ /Cl- co-transporter1 (NKCC1). These changes in chloride transport would result in increased [Cl- ]i in SON AVP neurones. The study combined virally-mediated chloride imaging with ClopHensorN with a single-cell western blot analysis. An adeno-associated virus with ClopHensorN and a vasopressin promoter (AAV2-0VP1-ClopHensorN) was bilaterally injected in the SON of adult male Sprague-Dawley rats that were either euhydrated (Eu) or salt-loaded (SL) for 7 days. Acutely dissociated SON neurones expressing ClopHensorN were tested for decreases or increases in [Cl- ]i in response to focal application of the GABAA agonist muscimol (100 µmol L-1 ). SON AVP neurones from Eu rats showed muscimol-induced chloride influx (P < 0.05;23/35). SON AVP neurones from SL rats either significantly increased chloride efflux (P < 0.05;27/39) or did not change chloride flux (12/39). The SON AVP neurones that responded to muscimol appeared to be viable and expressed KCC2 and ß-actin. Neurones that did not respond during chloride imaging did not show KCC2 and ß-actin protein expression. The KCC2 antagonist (VU0240551,10 µmol L-1 ) significantly blocked the chloride influx in cells from Eu rats but did not affect cells from SL rats. A NKCC1 antagonist (bumetanide,10 µmol L-1 ) significantly blocked the chloride efflux in cells from SL rats but had no effect on cells from Eu rats. Blocking NKCC1 using bumetanide had less of an effect on the muscimol-induced Cl- influx in Eu rat neurones compared to the KCC2 antagonist. The TrkB antagonist (AnA-12) (50 µmol L-1 ) and protein kinase inhibitor (K252a) (100 nmol L-1 ) each significantly blocked chloride efflux in SON AVP neurones from SL rats. Salt-loading increases [Cl- ]i in SON AVP neurones via a TrKB-KCC2-NKCC1-dependent mechanism in rats.

Selectively Inhibiting the Median Preoptic Nucleus Attenuates Angiotensin II and Hyperosmotic-Induced Drinking Behavior and Vasopressin Release in Adult Male Rats.

The median preoptic nucleus (MnPO) is a putative integrative region that contributes to body fluid balance. Activation of the MnPO can influence thirst, but it is not clear how these responses are linked to body fluid homeostasis. We used designer receptors exclusively activated by designer drugs (DREADDs) to determine the role of the MnPO in drinking behavior and vasopressin release in response to peripheral angiotensin II (ANG II) or 3% hypertonic saline (3% HTN) in adult male Sprague Dawley rats (250-300 g). Rats were anesthetized with isoflurane and stereotaxically injected with an inhibitory DREADD (rAAV5-CaMKIIa-hM4D(Gi)-mCherry) or control (rAAV5-CaMKIIa-mCherry) virus in the MnPO. After two weeks' recovery, a subset of rats was used for extracellular recordings to verify functional effects of ANG II or hyperosmotic challenges in MnPO slice preparations. Remaining rats were used in drinking behavior studies. Each rat was administered either 10 mg/kg of exogenous clozapine-N-oxide (CNO) to inhibit DREADD-expressing cells or vehicle intraperitoneal followed by a test treatment with either 2-mg/kg ANG II or 3% HTN (1 ml/100-g bw, s.c.), twice per week for two separate treatment weeks. CNO-induced inhibition during either test treatment significantly attenuated drinking responses compared to vehicle treatments and controls. Brain tissue processed for cFos immunohistochemistry showed decreased expression with CNO-induced inhibition during either test treatment in the MnPO and downstream nuclei compared to controls. CNO-mediated inhibition significantly attenuated treatment-induced increases in plasma vasopressin compared to controls. The results indicate inhibition of CaMKIIa-expressing MnPO neurons significantly reduces drinking and vasopressin release in response to ANG II or hyperosmotic challenge.

Angiotensin type 1a receptors in the median preoptic nucleus support intermittent hypoxia-induced hypertension.

Chronic intermittent hypoxia (CIH) is a model of the hypoxemia from sleep apnea that causes a sustained increase in blood pressure. Inhibition of the central renin-angiotensin system or FosB in the median preoptic nucleus (MnPO) prevents the sustained hypertensive response to CIH. We tested the hypothesis that angiotensin type 1a (AT1a) receptors in the MnPO, which are upregulated by CIH, contribute to this hypertension. In preliminary experiments, retrograde tract tracing studies showed AT1a receptor expression in MnPO neurons projecting to the paraventricular nucleus. Adult male rats were exposed to 7 days of intermittent hypoxia (cycling between 21% and 10% O2 every 6 min, 8 h/day during light phase). Seven days of CIH was associated with a FosB-dependent increase in AT1a receptor mRNA without changes in the permeability of the blood-brain barrier in the MnPO. Separate groups of rats were injected in the MnPO with an adeno-associated virus containing short hairpin (sh)RNA against AT1a receptors to test their role in intermittent hypoxia hypertension. Injections of shRNA against AT1a in MnPO blocked the increase in mRNA associated with CIH, prevented the sustained component of the hypertension during normoxia, and reduced circulating advanced oxidation protein products, an indicator of oxidative stress. Rats injected with shRNA against AT1a and exposed to CIH had less FosB staining in MnPO and the rostral ventrolateral medulla after intermittent hypoxia than rats injected with the control vector that were exposed to CIH. Our results indicate AT1a receptors in the MnPO contribute to the sustained blood pressure increase to intermittent hypoxia.