Impact of stress on cardiac phenotypes in mice harboring an ankyrin-B disease variant

Encoded by ANK2, ankyrin-B (AnkB) is a multifunctional adapter protein critical for the expression and targeting of key cardiac ion channels, transporters, cytoskeletal-associated proteins, and signaling molecules. Mice deficient for AnkB expression are neonatal lethal, and mice heterozygous for AnkB expression display cardiac structural and electrical phenotypes. Human ANK2 loss-of-function variants are associated with diverse cardiac manifestations; however, human clinical 'AnkB syndrome' displays incomplete penetrance. To date, animal models for human arrhythmias have generally been knock-out or transgenic overexpression models and thus the direct impact of ANK2 variants on cardiac structure and function in vivo is not clearly defined. Here, we directly tested the relationship of a single human ANK2 disease-associated variant with cardiac phenotypes utilizing a novel in vivo animal model. At baseline, young AnkBp.E1458G+/+ mice lacked significant structural or electrical abnormalities. However, aged AnkBp.E1458G+/+ mice displayed both electrical and structural phenotypes at baseline including bradycardia and aberrant heart rate variability, structural remodeling, and fibrosis. Young and old AnkBp.E1458G+/+ mice displayed ventricular arrhythmias following acute (adrenergic) stress. In addition, young AnkBp.E1458G+/+ mice displayed structural remodeling following chronic (transverse aortic constriction) stress. Finally, AnkBp.E1458G+/+ myocytes harbored alterations in expression and/or localization of key AnkB-associated partners, consistent with the underlying disease mechanism. In summary, our findings illustrate the critical role of AnkB in in vivo cardiac function as well as the impact of single AnkB loss-of-function variants in vivo. However, our findings illustrate the contribution and in fact necessity of secondary factors (aging, adrenergic challenge, pressure-overload) to phenotype penetrance and severity.

US racial and sex-based disparities in firearm-related death trends from 1981-2020

BACKGROUND

Firearms cause the most suicides (60%) and homicides (36%) in the US. The high lethality and availability of firearms make them a particularly dangerous method of attempted violence. The aim of this study was to study US trends in firearm suicide and homicide mortality and years of potential life lost before age 75 (YPLL-75) between 1981 and 2020.

METHODS

Data in this cross-sectional study were collected between 1981 and 2020 from the Centers for Disease Control and Prevention (CDC)'s WISQARS database for fatal injury and violence. Data from the US population were considered for all age groups and were divided by racial groups and sex for analysis.

RESULTS

Those most heavily impacted by firearm homicide were Black, with homicide age-adjusted death rates almost seven times higher than White people. A spike in firearm homicide deaths occurred between 2019 and 2020, with Black people having the largest increase (39%). White people had the highest rates of firearm suicide, and suicide death rates increased between 2019 and 2020. Increases in homicide and suicide YPLL-75 between 2011 and 2020 had most heavily impacted minority populations. Men had a firearm suicide rate that was seven times higher than women, and a firearm homicide rate that was five times higher than women.

CONCLUSION

This study demonstrated that Black and White men were most impacted by firearm deaths, and that firearm homicide and suicide rates increased between 2019 and 2020 for all racial groups except Asian/Pacific Islander. Our results suggest that prevention efforts should focus on specific demographic factors and articulate the urgency to mitigate firearm-related deaths in the US.

CRISPR Del/Rei: a simple, flexible, and efficient pipeline for scarless genome editing

Scarless genome editing of induced pluripotent stem cells (iPSCs) is crucial for the precise modeling of genetic disease. Here we present CRISPR Del/Rei, a two-step deletion-reinsertion strategy with high editing efficiency and simple PCR-based screening that generates isogenic clones in ~ 2 months. We apply our strategy to edit iPSCs at 3 loci with only rare off target editing.

Genetic and non-genetic risk factors associated with atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmic disorder and its prevalence in the United States is projected to increase to more than twelve million cases in 2030. AF increases the risk of other forms of cardiovascular disease, including stroke. As the incidence of atrial fibrillation increases dramatically with age, it is paramount to elucidate risk factors underlying AF pathogenesis. Here, we review tissue and cellular pathways underlying AF, as well as critical components that impact AF susceptibility including genetic and environmental risk factors. Finally, we provide the latest information on potential links between SARS-CoV-2 and human AF. Improved understanding of mechanistic pathways holds promise in preventative care and early diagnostics, and also introduces novel targeted forms of therapy that might attenuate AF progression and maintenance.

Giant ankyrin-G regulates cardiac function

Cardiovascular disease (CVD) remains the most common cause of adult morbidity and mortality in developed nations. As a result, predisposition for CVD is increasingly important to understand. Ankyrins are intracellular proteins required for the maintenance of membrane domains. Canonical ankyrin-G (AnkG) has been shown to be vital for normal cardiac function, specifically cardiac excitability, via targeting and regulation of the cardiac voltage-gated sodium channel. Noncanonical (giant) AnkG isoforms play a key role in neuronal membrane biogenesis and excitability, with evidence for human neurologic disease when aberrant. However, the role of giant AnkG in cardiovascular tissue has yet to be explored. Here, we identify giant AnkG in the myocardium and identify that it is enriched in 1-week-old mice. Using a new mouse model lacking giant AnkG expression in myocytes, we identify that young mice displayed a dilated cardiomyopathy phenotype with aberrant electrical conduction and enhanced arrhythmogenicity. Structural and electrical dysfunction occurred at 1 week of age, when giant AnkG was highly expressed and did not appreciably change in adulthood until advanced age. At a cellular level, loss of giant AnkG results in delayed and early afterdepolarizations. However, surprisingly, giant AnkG cKO myocytes display normal I_Na, but abnormal myocyte contractility, suggesting unique roles of the large isoform in the heart. Finally, transcript analysis provided evidence for unique pathways that may contribute to the structural and electrical findings shown in giant AnkG cKO animals. In summary, we identify a critical role for giant AnkG that adds to the diversity of ankyrin function in the heart.

Mating and social exposure induces an opioid-dependent conditioned place preference in male but not in female prairie voles (Microtus ochrogaster)

In rodents, sexual stimulation induces a positive affective state that is evaluated by the conditioned place preference (CPP) test. Opioids are released during sexual behavior and modulate the rewarding properties of this behavior. Prairie voles (Microtus ochrogaster) are a socially monogamous species, in which copulation with cohabitation for 6h induces a pair bond. However, the mating-induced reward state that could contribute to the establishment of the long-term pair bond has not been evaluated in this species. The present study aimed to determine whether one ejaculation or cohabitation with mating for 6h is rewarding for voles. We also evaluated whether this state is opioid dependent. Our results demonstrate that mating with one ejaculation and social cohabitation with mating for 6h induce a CPP in males, while exposure to a sexually receptive female without mating did not induce CPP. In the female vole, mating until one ejaculation, social cohabitation with mating, or exposure to a male without physical interaction for 6h did not induce CPP. To evaluate whether the rewarding state in males is opioid dependent, the antagonist naloxone was injected i.p. The administration of naloxone blocked the rewarding state induced by one ejaculation and by social cohabitation with mating. Our results demonstrate that in the prairie vole, on the basis of the CPP in the testing conditions used here, the stimulation received with one ejaculation and the mating conditions that lead to pair bonding formation may be rewarding for males, and this reward state is opioid dependent.

Coumestrol Antagonizes Neuroendocrine Actions of Estrogen via the Estrogen Receptor α

The phytoestrogen coumestrol has estrogenic actions on peripheral reproductive tissues. Yet in the brain this compound has both estrogenic and anti-estrogenic effects. We used estrogen receptor α knockout mice (ERαKO) to determine whether coumestrol has estrogenic actions in mice and also if these effects are mediated by the classic ERα. Female wild-type (WT) and ERαKO mice were ovariectomized and treated with estradiol (E2), dietary coumestrol, both, or neither compound. Ten days later the animals were sacrificed, blood was collected, and brain tissues were perfused. Fixed brains were sectioned and immunocytochemistry was employed to quantify progesterone receptors (PR) in the medial preoptic (POA) and ventromedial nucleus of the hypothalamus (VMN). Plasma was assayed for luteinizing hormone (LH). Estrogen treatment induced PR immunoreactivity in both regions in brains of WT females. In ERαKO mice, lower levels of PR were induced. The stimulatory effects of E2 on PR were attenuated in the POA by cotreatment with coumestrol, and the same trend was noted in the VMN. WT ovariectomized females treated with E2 had low levels of LH, while LH was high in untreated females and even higher in ovariectomized females treated with coumestrol. ERαKO females in all treatment groups had high levels of LH. Taken together, the results show that coumestrol has anti-estrogenic actions in the brain and pituitary and that ERα mediates these effects.

The common gamma chain cytokine interleukin-21 is expressed by activated lymphocytes from two macropod marsupials, Macropus eugenii and Onychogalea fraenata

In mammals, interleukin-21 is a member of the common gamma chain cytokine family that also includes IL-2, IL-4, IL-7, IL-9 and IL-15. IL-21 has pleiotropic effects on both myeloid and lymphoid immune cells and as a consequence, the biological actions of IL-21 are broad: regulating both innate and adaptive immune responses and playing a pivotal role in antiviral, inflammatory and antitumour cellular responses. While IL-21 genes have been characterized in mammals, birds, fish and amphibians, there are no reports for any marsupial species to date. We characterized the expressed IL-21 gene from immune tissues of two macropod species, the tammar wallaby (Macropus eugenii), a model macropod, and the closely related endangered bridled nailtail wallaby (Onychogalea fraenata). The open reading frame of macropod IL-21 is 462 nucleotides in length and encodes a 153-mer putative protein that has 46% identity with human IL-21. Despite the somewhat low amino acid conservation with other mammals, structural elements and residues essential for IL-21 conformation and receptor association were conserved in the macropod IL-21 predicted peptides. The detection of IL-21 gene expression in T-cell-enriched tissues, combined with analysis of the promotor region of the tammar wallaby gene, suggests that macropod IL-21 is expressed in stimulated T cells but is not readily detected in other cells and tissues. The similarity of gene expression profile and functionally important amino acid residues to eutherian IL-21 makes it unlikely that the differences in B- and T-cell responses that are reported for some marsupial species are due to a lack of important functional residues or IL-21 gene expression in this group of mammals.

Distributions of oxytocin and vasopressin 1a receptors in the Taiwan vole and their role in social monogamy

Social monogamy is a mating strategy rarely employed by mammalian species. Laboratory studies in socially monogamous prairie voles (Microtus ochrogaster) demonstrate that oxytocin and vasopressin act within the mesolimbic dopamine pathway to facilitate pair-bond formation. Species differences in oxytocin receptor (OTR) and vasopressin 1a receptor (V1aR) distribution in this pathway are associated with species differences in mating strategy. Here we characterize the neuroanatomical distribution of OTR and V1aR binding sites in naturally occurring populations of Taiwan voles (M. kikuchii), which purportedly display social monogamy. Live trapping was conducted at two sites in 2009-2010 and receptor autoradiography for OTR and V1aR was performed on brains from 24 animals. OTR binding in two brain regions where OTR signaling regulates pair-bonding were directly compared with that of prairie voles. Our results show that like prairie voles, Taiwan voles exhibit OTR in the prefrontal cortex, insular cortex, claustrum, nucleus accumbens, caudate-putamen, dorsal lateral septal nucleus, central amygdala, and ventromedial hypothalamus. Unlike prairie voles, Taiwan voles exhibit OTR binding in the CA3 pathway of the hippocampus, as well as the indusium griseum, which has only previously been documented in tuco-tucos (Ctenomys haigi, C. sociabilis), Syrian hamsters (Mesocricetus auratus) and naked mole-rats (Heterocephalus glaber). V1aR binding was present in the ventral pallidum, lateral septum, nucleus basalis, bed nucleus of the stria terminalis, hippocampus, medial amygdala, and anterior, ventromedial and dorsomedial hypothalamus. Marked individual differences in V1aR binding were noted in the cingulate cortex and several thalamic nuclei, remarkably similar to prairie voles. While pharmacological studies are needed to determine whether oxytocin and vasopressin are involved in pair-bond formation in this species, our results lay a foundation for future investigations into the role of these neuropeptides in Taiwan vole social behavior.

The influence of AVPR1A genotype on individual differences in behaviors during a mirror self-recognition task in chimpanzees (Pan troglodytes)

The mark/rouge test has been used to assess mirror self-recognition (MSR) in many species. Despite consistent evidence of MSR in great apes, genetic or non-genetic factors may account for the individual differences in behavioral responses that have been reported. We examined whether vasopressin receptor gene (AVPR1A) polymorphisms are associated with MSR-related behaviors in chimpanzees since vasopressin has been implicated in the development and evolution of complex social relations and cognition and chimpanzees are polymorphic for the presence of the RS3-containing DupB region. We compared a sample of DupB+/- and DupB-/- chimpanzees on a mark test to assess its role on social behavior toward a mirror. Chimpanzees were administered two, 10-min sessions where frequencies of mirror-guided self-directed behaviors, contingent actions and other social behaviors were recorded. Approximately one-third showed evidence of MSR and these individuals exhibited more mirror-guided self-exploratory behaviors and mouth contingent actions than chimpanzees not classified as passers. Moreover, DupB+/- males exhibited more scratching and agonistic behaviors than other male and female cohorts. Our findings support previous studies demonstrating individual differences in MSR abilities in chimpanzees and suggest that AVPR1A partly explains individual differences in MSR by influencing the behavioral reactions of chimpanzees in front of a mirror.

Oxytocin-dependent consolation behavior in rodents

Consolation behavior toward distressed others is common in humans and great apes, yet our ability to explore the biological mechanisms underlying this behavior is limited by its apparent absence in laboratory animals. Here, we provide empirical evidence that a rodent species, the highly social and monogamous prairie vole (Microtus ochrogaster), greatly increases partner-directed grooming toward familiar conspecifics (but not strangers) that have experienced an unobserved stressor, providing social buffering. Prairie voles also match the fear response, anxiety-related behaviors, and corticosterone increase of the stressed cagemate, suggesting an empathy mechanism. Exposure to the stressed cagemate increases activity in the anterior cingulate cortex, and oxytocin receptor antagonist infused into this region abolishes the partner-directed response, showing conserved neural mechanisms between prairie vole and human.

Regional differences in mu and kappa opioid receptor G-protein activation in brain in male and female prairie voles

Prairie voles are unusual mammals in that, like humans, they are capable of forming socially monogamous pair bonds, display biparental care, and engage in alloparental behaviors. Both mu and kappa opioid receptors are involved in behaviors that either establish and maintain, or result from pair bond formation in these animals. Mu and kappa opioid receptors both utilize inhibitory G-proteins in signal transduction mechanisms, however the efficacy by which these receptor subtypes stimulate G-protein signaling across the prairie vole neuraxis is not known. Utilizing [(35)S]GTPγS autoradiography, we characterized the efficacy of G-protein stimulation in coronal sections throughout male and female prairie vole brains by [D-Ala2,NMe-Phe4,Gly-ol5]-enkephalin (DAMGO) and U50,488H, selective mu and kappa opioid agonists, respectively. DAMGO stimulation was highest in the forebrain, similar to that found with other rodent species. U-50,488H produced greater stimulation in prairie voles than is typically seen in mice and rats, particularly in select forebrain areas. DAMGO produced higher stimulation in the core versus the shell of the nucleus accumbens (NAc) in females, while the distribution of U-50,488H stimulation was the opposite. There were no gender differences for U50,488H stimulation of G-protein activity across the regions examined, while DAMGO stimulation was greater in sections from females compared to those from males for NAc core, entopeduncular nucleus, and hippocampus. These data suggest that the kappa opioid system may be more sensitive to manipulation in prairie voles compared to mice and rats, and that female prairie voles may be more sensitive to mu agonists in select brain regions than males.

Neuroanatomical distribution of oxytocin and vasopressin 1a receptors in the socially monogamous coppery titi monkey (Callicebus cupreus)

The coppery titi monkey (Callicebus cupreus) is a socially monogamous New World primate that has been studied in the field and the laboratory to investigate the behavioral neuroendocrinology of primate pair bonding and parental care. Arginine vasopressin has been shown to influence male titi monkey pair-bonding behavior, and studies are currently underway to examine the effects of oxytocin on titi monkey behavior and physiology. Here, we use receptor autoradiography to identify the distribution of arginine vasopressin 1a receptor (AVPR1a) and oxytocin receptors (OXTR) in hemispheres of titi monkey brain (n=5). AVPR1a are diffuse and widespread throughout the brain, but the OXTR distribution is much more limited, with the densest binding being in the hippocampal formation (dentate gyrus, CA1 field) and the presubiculum (layers I and III). Moderate OXTR binding was detected in the nucleus basalis of Meynert, pulvinar, superior colliculus, layer 4C of primary visual cortex, periaqueductal gray (PAG), pontine gray, nucleus prepositus, and spinal trigeminal nucleus. OXTR mRNA overlapped with OXTR radioligand binding, confirming that the radioligand was detecting OXTR protein. AVPR1a binding is present throughout the cortex, especially in cingulate, insular, and occipital cortices, as well as in the caudate, putamen, nucleus accumbens, central amygdala, endopiriform nucleus, hippocampus (CA4 field), globus pallidus, lateral geniculate nucleus, infundibulum, habenula, PAG, substantia nigra, olivary nucleus, hypoglossal nucleus, and cerebellum. Furthermore, we show that, in the titi monkey brain, the OXTR antagonist ALS-II-69 is highly selective for OXTR and that the AVPR1a antagonist SR49059 is highly selective for AVPR1a. Based on these results and the fact that both ALS-II-69 and SR49059 are non-peptide, small-molecule antagonists that should be capable of crossing the blood-brain barrier, these two compounds emerge as excellent candidates for the pharmacological manipulation of OXTR and AVPR1a in future behavioral experiments in titi monkeys and other primate species.

A polymorphic indel containing the RS3 microsatellite in the 5' flanking region of the vasopressin V1a receptor gene is associated with chimpanzee (Pan troglodytes) personality

Vasopressin is a neuropeptide that has been strongly implicated in the development and evolution of complex social relations and cognition in mammals. Recent studies in voles have shown that polymorphic variation in the promoter region of the arginine vasopressin V1a receptor gene (avpr1a) is associated with different dimensions of sociality. In humans, variation in a repetitive sequence element in the 5' flanking region of the AVPR1A, known as RS3, have also been associated with variation in AVPR1a gene expression, brain activity and social behavior. Here, we examined the association of polymorphic variation in this same 5' flanking region of the AVPR1A on subjective ratings of personality in a sample of 83 chimpanzees (Pan troglodytes). Initial analyses indicated that 34 females and 19 males were homozygous for the short allele, which lacks RS3 (DupB(-/-)), while 18 females and 12 males were heterozygous and thus had one copy of the long allele containing RS3 (DupB(+/-)), yielding overall allelic frequencies of 0.82 for the DupB(-) allele and 0.18 for the DupB(+) allele. DupB(+/+) chimpanzees were excluded from the analysis because of the limited number of individuals. Results indicated no significant sex difference in personality between chimpanzees homozygous for the deletion of the RS3-containing DupB region (DupB(-/-)); however, among chimpanzees carrying one allele with the DupB present (DupB(+/-)), males had significantly higher dominance and lower conscientiousness scores than females. These findings are the first evidence showing that the AVPR1A gene plays a role in different aspects of personality in male and female chimpanzees.

Molecular identification of interleukin-2 in the lymphoid tissues of the common brushtail possum, Trichosurus vulpecula

The common brushtail possum (Trichosurus vulpecula) is an Australian marsupial. Here we describe the identification of possum interleukin-2 in mitogen-stimulated lymph node cells. We used a strategy of Rapid amplification of cDNA ends using probes designed from recently-sequenced marsupial genomes to identify the IL2 gene and then confirmed that IL-2 expression in possum immune tissue occurs in a similar manner to that in their eutherian counterparts. The predictive possum IL-2 peptide showed 28% and 35% amino acid sequence homology with the mouse and human IL-2 molecules, respectively, consistent with the divergence found within this cytokine family. Despite this low sequence identity, possum IL-2 still possessed the characteristic hallmarks of mammalian IL-2, such as a predicted signal peptide and conserved family motifs.

Seasonal abundance of anopheline mosquitoes and their association with rainfall and malaria along the Matapí River, Amapá, [corrected] Brazil

Three communities separated by 1.5-7.0 km, along the Matapí River, Amapá State, Brazil, were sampled monthly from April 2003 to November 2005 to determine relationships between seasonal abundance of host-seeking anophelines, rainfall and malaria cases. Out of the 759 821 adult female anophelines collected, Anopheles darlingi Root (Diptera: Culicidae) was the most abundant (56.2%) followed by An. marajoara Galvão & Damasceno (24.6%), An. nuneztovari Gabaldón (12.4%), An. intermedius (Chagas) (4.4%) and An. triannulatus (Neiva and Pinto) (2.3%). Vector abundance, as measured by human landing catches, fluctuated during the course of the study and varied in species-specific ways with seasonal patterns of rainfall. Anopheles darlingi and An. triannulatus were more abundant during the wet-dry transition period in June to August, whereas An. marajoara began to increase in abundance in February in two villages, and during the wet-dry transition in the other village. Anopheles nuneztovari and An. intermedius increased in abundance shortly after the rains began in January to February. A generalized linear mixed model (GLMM) analysis of 32 consecutive months of collections showed significant differences in abundance for each species by village and date (P < 0.0001). Correlations between lagged rainfall and abundances also differed among species. A strong positive correlation of An. darlingi abundance with rainfall lagged by 4 and 5 months (Pearson's r = 0.472-0.676) was consistent among villages and suggests that rainfall may predict vector abundance. Significant correlations were detected between numbers of malaria cases and abundances of suspected vector species. The present study shows how long-term field research may connect entomological and climatological correlates with malaria incidence.

Scrub-itch mite infestation in the endangered bridled nailtail wallaby

Skin lesions on the ears and inguinal and axillary regions of a number of adult animals within a captive population of the endangered bridled nailtail wallaby (Onychogalea fraenata) were associated with the trombiculid mite, Eutrombicula hirsti. The local inflammatory response of these Australian marsupials is described.

Culture and Stimulation of Tammar Wallaby Lymphocytes

We describe the culture and stimulation of lymphocytes from the model marsupial, the tammar wallaby (Macropus eugenii). We also describe the capacity of tammar wallaby lymphocytes isolated from blood, spleen and lymph nodes to produce soluble immunomodulatory factors. Culture conditions were optimized for mitogen-driven stimulation using the plant lectin phytohaemagglutinin (PHA). Products secreted by stimulated cells were harvested and crudely fractionated before they were added back to freshly isolated lymphocytes. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay, both stimulatory and inhibitory bioactive factors were detected in serum-free supernatants harvested from mitogen-treated peripheral blood mononuclear cells. This paper describes the capacity of leukocytes of the tammar wallaby to respond to mitogenic stimulation and to produce soluble, low-molecular-weight bioactive molecules that possess cytokine-like activity.

Neonatal oxytocin manipulations have long-lasting, sexually dimorphic effects on vasopressin receptors

Developmental exposure to oxytocin (OT) or oxytocin antagonists (OTAs) has been shown to cause long-lasting and often sexually dimorphic effects on social behaviors in prairie voles (Microtus ochrogaster). Because regulation of social behavior in monogamous mammals involves central receptors for OT, arginine vasopressin (AVP), and dopamine, we examined the hypothesis that the long-lasting, developmental effects of exposure to neonatal OT or OTA might reflect changes in the expression of receptors for these peptides. On postnatal day 1, prairie voles were injected intraperitoneally with either OT (1 mg/kg), an OTA (0.1 mg/kg), saline vehicle, or were handled only. At approximately 60 days of age, vasopressin V1a receptors, OT receptors (OTR) and dopamine D2 receptor binding were quantified using receptor autoradiography in brain tissue taken from males and females. Significant treatment effects on V1a binding were found in the bed nucleus of the stria terminalis (BNST), cingulate cortex (CgCtx), mediodorsal thalamus (MdThal), medial preoptic area of the hypothalamus (MPOA), and lateral septum (LS). The CgCtx, MPOA, ventral pallidum, and LS also showed significant sex by treatment interactions on V1a binding. No significant treatment or sex differences were observed for D2 receptor binding. No significant treatment difference was observed for OTR receptor binding, and only a marginal sex difference. Changes in the neuropeptide receptor expression, especially the V1a receptor, may help to explain sexually dimorphic changes in behavior that follow comparable neonatal manipulations.

Species and individual differences in juvenile female alloparental care are associated with oxytocin receptor density in the striatum and the lateral septum

The neuropeptide oxytocin has been implicated in the regulation of affiliative behavior and maternal responsiveness in several mammalian species. Rodent species vary considerably in the expression of juvenile alloparental behavior. For example, alloparental behavior is spontaneous in juvenile female prairie voles (approximately 20 days of age), takes 1-3 days of pup exposure to develop in juvenile rats, and is nearly absent in juvenile mice and meadow voles. Here, we tested the hypothesis that species differences in pup responsiveness in juvenile rodents are associated with oxytocin receptor (OTR) density in specific brain regions. We found that OTR density in the nucleus accumbens (NA) is highest in juvenile prairie voles, intermediate in juvenile rats, and lowest in juvenile mice and meadow voles. In the caudate putamen (CP), OTR binding was highest in prairie voles, intermediate in rats and meadow voles, and lowest in mice. In contrast, the lateral septum (LS) shows an opposite pattern, with OTR binding being high in mice and meadow voles and low in prairie voles and rats. Thus, alloparental responsiveness in juvenile rodents is positively correlated with OTR density in the NA and CP and negatively correlated with OTR density in the LS. We then investigated whether a similar receptor-behavior relationship exists among juvenile female prairie voles by correlating individual variation in alloparental behavior with variation in OTR density. The time spent adopting crouching postures, the most distinctive component of alloparental behavior in juveniles, was positively correlated with OTR density in the NA (r = 0.47) and CP (r = 0.45) and negatively correlated with OTR density in the lateral septum (r = -0.53). Thus, variation in OTR density in the NA, CP, and LS may underlie both species and individual differences in alloparental care in rodents.

Oxytocin receptors in the nucleus accumbens facilitate “spontaneous” maternal behavior in adult female prairie voles

Oxytocin and the nucleus accumbens have been extensively implicated in the regulation of maternal behavior, and the processing of pup-related stimuli relevant for this behavior. Oxytocin receptor density in the nucleus accumbens is highly variable in virgin female prairie voles, as is their behavioral response to pups, ranging from neglecting and infanticidal to full maternal behavior. We hypothesized that oxytocin receptor in the nucleus accumbens facilitates the expression of "spontaneous" maternal behavior in prairie voles. Forty sexually-naive adult females were exposed to pups for the first time and tested for maternal behavior. Oxytocin receptor binding in the nucleus accumbens and other brain regions was later determined using autoradiography. Females that showed maternal behavior (lick and groom the pups and hover over them for at least 30 s, n=24) had higher oxytocin receptor density in the nucleus accumbens (shell subregion) (P<0.05) than females that did not show maternal behavior or attacked the pups (n=16). No differences were found in other brain regions (medial preoptic area, septum, prelimbic cortex). In a second experiment, we tested whether infusions of the oxytocin receptor antagonist (d(CH2)5(1),Tyr(Me)2,Orn8)-AVT into the nucleus accumbens would block "spontaneous" maternal behavior. As a control region, oxytocin receptor antagonist was also infused into the caudate putamen. Ten females were infused bilaterally into the nucleus accumbens or caudate putamen with either 2 ng/0.5 microl of oxytocin receptor antagonist or CSF (vehicle). While five of 10 nucleus accumbens CSF-infused animals showed maternal behavior, none of the nucleus accumbens oxytocin receptor antagonist-infused subjects did (0/10; chi2, P<0.01). Nucleus accumbens oxytocin receptor antagonist-infused females recovered the next day and were not different from controls. Animals infused with CSF or oxytocin receptor antagonist into the caudate putamen did not differ (four/10, four/10). This is the first study to show that the nucleus accumbens is involved in the regulation of "spontaneous" maternal behavior and that oxytocin receptor in this brain region facilitates maternal responses.

Association of vasopressin 1a receptor levels with a regulatory microsatellite and behavior

Vasopressin regulates complex behaviors such as anxiety, parenting, social engagement and attachment and aggression in a species-specific manner. The capacity of vasopressin to modulate these behaviors is thought to depend on the species-specific distribution patterns of vasopressin 1a receptors (V1aRs) in the brain. There is considerable individual variation in the pattern of V1aR binding in the brains of the prairie vole species, Microtus ochrogaster. We hypothesize that this individual variability in V1aR expression levels is associated with individual variation in a polymorphic microsatellite in the 5' regulatory region of the prairie vole v1ar gene. Additionally, we hypothesize that individual variation in V1aR expression contributes to individual variation in vasopressin-dependent behaviors. To test these hypotheses, we first screened 20 adult male prairie voles for behavioral variation using tests that measure anxiety-related and social behaviors. We then assessed the brains of those animals for V1aR variability with receptor autoradiography and used polymerase chain reaction to genotype the same animals for the length of their 5' microsatellite polymorphism in the v1ar gene. In this report, we describe the results of this discovery-based experimental approach to identify potential gene, brain and behavior interrelationships. The analysis reveals that V1aR levels, in some but not all brain regions, are associated with microsatellite length and that V1aR levels in those and other brain regions correlate with anxiety-related and social behaviors. These results generate novel hypotheses regarding neural control of anxiety-related and social behaviors and yield insight into potential mechanisms by which non-coding gene polymorphisms may influence behavioral traits.

Culture and characterisation of peripheral blood monocytes and monocyte-derived adherent cells of the tammar wallaby, Macropus eugenii

Monocytes, monocyte-derived adherent cells and dendritic cells all play a role in cellular immunity. In this study, we describe the isolation of monocyte-derived adherent cells and dendritic cells from a model marsupial, the tammar wallaby, Macropus eugenii, and report that in vitro, these cells appear morphologically similar to these cells found in other mammals. The successful culture of marsupial monocyte and dendritic cells was undertaken in serum-free medium which contained lymphocyte conditioned medium as an absolute requirement. This supports the view that similar to cultured dendritic cells from other species reported to date, specific growth factors are required to promote the maturation and differentiation of these cells.

A method for acetylcholinesterase staining of brain sections previously processed for receptor autoradiography

Receptor autoradiography using selective radiolabeled ligands allows visualization of brain receptor distribution and density on film. The resolution of specific brain regions on the film often can be difficult to discern owing to the general spread of the radioactive label and the lack of neuroanatomical landmarks on film. Receptor binding is a chemically harsh protocol that can render the tissue virtually unstainable by Nissl and other conventional stains used to delineate neuroanatomical boundaries of brain regions. We describe a method for acetylcholinesterase (AChE) staining of slides previously processed for receptor binding. AChE staining is a useful tool for delineating major brain nuclei and tracts. AChE staining on sections that have been processed for receptor autoradiography provides a direct comparison of brain regions for more precise neuroanatomical description. We report a detailed thiocholine protocol that is a modification of the Koelle-Friedenwald method to amplify the AChE signal in brain sections previously processed for autoradiography. We also describe several temporal and experimental factors that can affect the density and clarity of the AChE signal when using this protocol.

Vasopressin-dependent neural circuits underlying pair bond formation in the monogamous prairie vole

Arginine vasopressin and its V1a receptor subtype (V1aR) are critical for pair bond formation between adult prairie voles. However, it is unclear which brain circuits are involved in this vasopressin-mediated facilitation of pair bond formation. Here, we examined mating-induced Fos expression in several brain regions involved in sociosexual and reward circuitry in male prairie voles. Consistent with studies in other species, Fos expression was induced in several regions known to be involved in sociosexual behavior, namely, the medial amygdala, bed nucleus of the stria terminalis, and medial preoptic area. Fos induction also occurred in limbic and reward regions, including the ventral pallidum, nucleus accumbens, and mediodorsal thalamus (MDthal). Next, we infused a selective V1aR antagonist into three candidate brain regions that seemed most likely involved in vasopressin-mediated pair bond formation: the ventral pallidum, medial amygdala, and MDthal. Blockade of V1aR in the ventral pallidum, but not in the medial amygdala or MDthal, prevented partner preference formation. Lastly, we demonstrated that the mating-induced Fos activation in the ventral pallidum was vasopressin-dependent, since over-expression of V1aR using viral vector gene transfer resulted in a proportionate increase in mating-induced Fos in the same region. This is the first study to show that vasopressin neurotransmission occurs in the ventral pallidum during mating, and that V1aR activation in this region is necessary for pair bond formation in male prairie voles. The results from this study have profound implications for the neural circuitry underlying social attachment and generate novel hypotheses regarding the neural control of social behavior.

The role of vasopressin in the genetic and neural regulation of monogamy

Arginine vasopressin modulates pairbond formation in the monogamous prairie vole (Microtus ochrogaster). Our laboratory has investigated the genetic and neural mechanisms by which vasopressin and its V1a receptor (V1aR) regulate social attachment between mates. Non-monogamous vole species show strikingly different distribution patterns of brain V1aR expression compared to monogamous species, and these patterns are thought to arise from species differences in the respective promoter sequences of the V1aR gene. Individual differences in prairie vole V1aR patterns may also reflect individual differences in promoter sequences. Pharmacological and genetic manipulation of the specific brain regions that express V1aR in the 'monogamous pattern' allows multilevel examination of the neural circuits that underlie pairbond formation in monogamous species. For example, V1aR are expressed in brain regions involved in reward circuitry in monogamous vole species and have been implicated in pairbonding. V1aR are also highly expressed in regions implicated in the olfactory processing of sociosexual behaviour. We hypothesize that both circuits of reward and olfactory memory underlie the cognitive mechanisms that control pairbonding. When used in conjuction, genetic and cellular analyses of a complex social behaviour can provide a coherent framework with which to examine the role of the vasopressin system in species evolution and neural control of behaviour.

The effects of neonatal castration on the subsequent behavioural response to centrally administered arginine vasopressin and the expression of V1a receptors in adult male prairie voles

Centrally administered arginine vasopressin induces the formation of partner preferences in male prairie voles (Microtus ochrogaster). The expression of many vasopressin-regulated behaviours is testosterone dependent. In this study, we tested the hypothesis that early exposure to gonadal steroids are necessary to establish the typical response of adult male prairie voles to exogenous vasopressin, predicting that adult males which were castrated neonatally would not form partner preferences in response to centrally administered vasopressin. We also examined the effect of neonatal castration on the expression of vasopressin (V1a) receptors. Voles were castrated on the day of birth (NEOCAST), sham-castrated on the day of birth (NEOSHAM) or castrated as adults (ADULTCAST). With the exception of one group of neonatal sham males (NEOSHAM CON), which served as a control for the effects of vasopressin, as adults, all males received a 1- micro l intracerebroventricular injection of vasopressin (100 ng) in artificial cerebrospinal fluid. In addition, 2 weeks before testing, one group of neonatally castrated males received an implant of testosterone propionate (NEOCAST + TP). Between 60 and 90 days of age, an internal cannula was placed in the lateral cerebral ventricle and, 24 h later, males were injected with vasopressin. Subsequently, after an additional 15 min, males were cohabitated with a female 'partner' for 1 h. Immediately following cohabitation, males were placed in a Y-shaped partner preference test apparatus for 3 h, in which the male had access to the 'partner' and a novel female, 'stranger.' Time spent with the partner versus the stranger was compared within and between treatments. The results were found to support our hypothesis as the NEOSHAM and ADULTCAST males formed partner preferences, spending more time with the partner, and they spent significantly more time with their partner than did NEOSHAM CON, NEOCAST or NEOCAST + TP males. Replacement of testosterone in neonatally castrated males did not restore partner preference formation in response to vasopressin in adult males. Finally, neonatal castration did not affect the distribution of V1a receptors.

Do guidelines improve the process and outcomes of care in delirium?

OBJECTIVE

To develop consensus guidelines for management of delirium and to assess their effectiveness in improving the outcomes and process of care in delirium.

METHOD

Guidelines for delirium were developed following a literature search and a formal multi-disciplinary consensus process using a two-stage Delphi technique. The process and outcomes of patients with delirium were then observed in a 'before' (211 patients) and an 'after' study (125 patients). Three levels of intervention were made in the 'after' study. (i) Feedback of baseline data only (low intensity intervention). (ii) As in (i), but also formal distribution of the guidelines to nurses and doctors (medium intensity intervention). (iii) As in (ii), but in addition the guidelines were reinforced with teaching sessions for the nurses and doctors (high intensity intervention).

SETTING

Older people (aged over 65 years) with delirium admitted to acute medical or acute elderly care wards in five district general hospitals in England.

RESULTS

Only in the high intervention group was there an improvement in process and outcome of care, but this failed to reach statistical significance.

CONCLUSION

Delirium is a poorly managed condition in older people and guidelines alone fail to improve the process and outcomes of care.

Oxytocin, but not oxytocin receptor, is rRegulated by oestrogen receptor beta in the female mouse hypothalamus

In the female rat, oestrogen receptor (ER) beta is colocalized with both oxytocin- and vasopressin-producing neurones in the paraventricular nucleus of the hypothalamus (PVN). In this study, we demonstrate that the same pattern of colocalization between ERbeta and oxytocin exists in the female mouse. Because this nucleus contains only a negligible quantity of ERalpha, it is likely that the oestrogen-dependent regulation of oxytocin and vasopressin synthesis in the PVN is mediated by ERbeta. Thus, we compared the effect of ovarian hormones on oxytocin and vasopressin mRNA expression in the PVN of wild-type (WT) and ERbeta knockout (betaERKO) mice. We also compared the effects of ovarian hormones on oxytocin receptor (OTR) expression in the medial amygdala (MeA) and ventromedial nucleus of the hypothalamus (VMN) in female WT and betaERKO mice. Ovariectomized mice underwent long-term treatment with oestradiol or oil. Progesterone was given concurrently on the final 7 days of treatment, and all mice were killed 48 h after the final progesterone injection. In the PVN, hormone treatment increased oxytocin mRNA expression in WT but not betaERKO females. These results suggest that ERbeta is necessary for the regulation of the expression of oxytocin in the PVN. Hormone treatment had no effect on vasopressin mRNA expression in the PVN, but significantly increased OTR binding in both the VMN and the MeA in both genotypes. Collectively, our data show region and peptide specific regulation by ERalpha and ERbeta in the mouse hypothalamus.

Uncoupling of 5-HT1A receptors in the brain by estrogens: regional variations in antagonism by ICI 182,780

Previously we have shown that 17beta-estradiol (in vivo and in vitro) rapidly decreases the function of serotonin(1A) (5-HT(1A)) receptors, allowing us to hypothesize that 17beta-estradiol accomplished this via activation of a membrane estrogen receptor. Hippocampus and frontal cortex obtained from ovariectomized rats were incubated with 17beta-estradiol or bovine serum albumin (BSA)-estradiol in the presence or absence of the estrogen receptor (ER) antagonist ICI 182,780. Membranes were prepared to measure R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding (a measure of 5-HT(1A) receptor coupling and function). In both hippocampus and frontal cortex, 17beta-estradiol and BSA-estradiol (50 nM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 blocked the effect of both the estrogens in hippocampus, but only the effect of 17beta-estradiol in frontal cortex. Due to the inability of ICI 182,780 to block the effects of BSA-estradiol in frontal cortex, similar experiments were performed using the selective estrogen receptor modulator tamoxifen as the agonist. Tamoxifen (100 nM and 1 microM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 (1 microM) blocked the ability of tamoxifen to decrease 5-HT(1A) receptor coupling in the hippocampus, but not in the frontal cortex. Taken together, these data support the existence of a pharmacologically distinct ER in hippocampus vs. frontal cortex that might be responsible for rapid uncoupling of 5-HT(1A) receptors.

Histological and immunohistological investigation of the lymphoid tissue in normal and mycobacteria-affected specimens of the Rufous Hare-wallaby (Lagorchestes hirsutus)

The histology of the spleen, lymph nodes, Gut-associated lymphoid tissue (GALT) and Bronchus-associated lymphoid tissue (BALT) are described for samples collected opportunistically from healthy and mycobacteria-affected specimens of the endangered marsupial Lagorchestes hirsutus, the Rufous Hare-wallaby. The structural elements, organization and distribution of T and B lymphocytes determined by immunohistological techniques using species cross-reactive antibodies in the lymph nodes, spleen and GALT of this species demonstrated lymphoid cell distributions that were consistent with other marsupial and eutherian mammals. The tissues of animals identified as acid-fast positive displayed immunopathology consistent with the responses to intracellular bacteria displayed in some eutherian mammals and included the presence of focal lesions, giant cells in the lung and lymphoid aggregations situated adjacent to blood and airway vessels. This is the first study to describe the lymphoid tissue of this rare macropod species and the first to document the tissue bed response to mycobacteria.

Transmission disequilibrium testing of arginine vasopressin receptor 1A (AVPR1A) polymorphisms in autism

Impairment in social reciprocity is a central component of autism. In preclinical studies, arginine vasopressin (AVP) has been shown to increase a range of social behaviors, including affiliation and attachment, via the V(1a) receptor (AVPR1A) in the brain. Both the behavioral effects of AVP and the neural distribution of the V1a receptor vary greatly across mammalian species. This difference in regional receptor expression as well as differences in social behavior may result from a highly variable repetitive sequence in the 5' flanking region of the V1a gene (AVPR1A). Given this comparative evidence for a role in inter-species variation in social behavior, we explored whether within our own species, variation in the human AVPR1A may contribute to individual variations in social behavior, with autism representing an extreme form of social impairment. We genotyped two microsatellite polymorphisms from the 5' flanking region of AVPR1A for 115 autism trios and found nominally significant transmission disequilibrium between autism and one of the microsatellite markers by Multiallelic Transmission/Disequilibrium test (MTDT) that was not significant after Bonferroni correction. We also screened approximately 2 kb of the 5' flanking region and the coding region and identified 10 single nucleotide polymorphisms.

Naturally occurring differences in maternal care are associated with the expression of oxytocin and vasopressin (V1a) receptors: gender differences

Variations in maternal care have been associated with long-term changes in neurochemistry and behaviour in adult rats. Rats receiving high levels of licking and grooming as pups are less fearful and more maternal than rats receiving low levels of maternal licking and grooming. Central pathways for oxytocin and vasopressin have been implicated in the neurobiology of anxiety and social behaviours. We assessed whether variations in maternal care were associated with differences in oxytocin receptors (OTR) or vasopressin (V1a) receptors in the brains of adult offspring. In the central nucleus of the amygdala and bed nucleus of the stria terminalis, OTR binding was increased in adult females, but not adult males, that had received high levels of maternal licking and grooming as pups. Conversely, amygdala V1a receptor binding was increased in males, but not females, that had received high levels of maternal licking and grooming. These findings suggest that variations in maternal care may influence the expression of oxytocin and vasopressin receptors in a gender-specific manner.

Dispersal of adult European corn borer (Lepidoptera: Crambidae) within and proximal to irrigated and non-irrigated corn

The European corn borer, Ostrinia nubilalis (Hübner), causes economic damage to corn, Zea mays L., throughout the Corn Belt. Because this insect has become the primary target of Bacillus thuringiensis Berliner (Bt) transgenic corn, current efforts addressing the management of O. nubilalis resistance to Bt corn require information on adult European corn borer dispersal and factors affecting its dispersal. In 1998 we conducted mark-release-recapture, release-recapture, and caged-mating studies to directly measure and compare local dispersal patterns of O. nubilalis adults within and proximal to irrigated and non-irrigated cornfields. Releases of marked adults were made corresponding to the first and second flight of O. nubilalis in eastern Nebraska. Adult dispersal was significantly different between irrigated and non-irrigated cornfields. Released adults tended to remain in and near irrigated cornfields, but dispersed out of and away from non-irrigated cornfields. When released at the edge of the cornfield, neither male nor unmated female O. nubilalis displayed an initial tendency to move out of irrigated corn and into the mixed smooth bromegrass (Bromus inermis Leyss) and broadleaf-weed field edge. Mating efficiency in a late-season cornfield was not significantly different than in dense foxtail (Setaria spp.). Generally, we found that adult O. nubilalis dispersal may vary depending on variables such as action-site availability and agronomic practices and their interaction with O. nubilalis life history.

Transgenic Polyoma middle-T mice model premalignant mammary disease

Mice transgenic for the Polyomavirus middle T (PyV-mT) gene have been widely used to study mammary tumorigenesis and metastasis. Although numerous molecular insights were gained from the analysis of these transgenic malignant tumors, the early events leading to malignant transformation have not been systematically investigated nor has the biological potential of hyperplastic lesions been documented. This paper presents the first comprehensive histopathological characterization of transgenic PyV-mT hyperplasias together with classical transplantation experiments designed to test the growth potential of these lesions. Moreover, stable hyperplastic outgrowth lines were established as a tool to study premalignant PyV-mT-induced hyperplasias in detail. Each line has a different tumor latency, indicating that PyV-mT-induced hyperplasias, like early proliferative lesions seen in the human breast, are heterogeneous with respect to their malignant potential. Our results settle a controversy; they establish that PyV-mT gene expression alone is insufficient to induce tumors and that additional events are required for tumorigenesis and metastasis. These results support the use of PyV-mT transgenic mice as a model for investigating the multistep progression of malignant mammary tumorigenesis and metastasis.

Oxytocin: who needs it?

The neuropeptide oxytocin has been implicated in the initiation of maternal behavior, based on studies in rats and sheep. Females in both of these species naturally avoid infants until parturition when they begin to show an intense interest in maternal care. Oxytocin pathways in the brain appear to be important for this transition from avoidance to approach of the young. Recent studies in mice with a null mutation of the oxytocin gene suggest a different scenario. These mice, which completely lack oxytocin, exhibit full maternal and reproductive behavior, except for a deficit in milk ejection. Apparently, oxytocin is not essential for maternal behavior in this species. Consistent with the role of oxytocin for the transition from avoidance to approach in rats and sheep, nulliparous mice show full maternal behavior and therefore do not require the peptide for the initiation of maternal care. The species differences in the behavioral effects of oxytocin are associated with profound species differences in the location of oxytocin receptors in the brain. Recent transgenic studies suggest that these species differences in the neuroanatomical distribution of oxytocin receptors may be a function of inter-species variation in the flanking region of the oxytocin receptor gene. So, who needs oxytocin? For maternal care, not mice and (possibly) other species, like primates, with promiscuous parental care. Most important, in considering the behavioral or cognitive functions of oxytocin, one cannot accurately extrapolate across species unless one knows the species have the same neuroanatomical location of oxytocin receptors.

Oxytocin in the medial amygdala is essential for social recognition in the mouse

Oxytocin (OT) knock-out mice fail to recognize familiar conspecifics after repeated social exposures, despite normal olfactory and spatial learning abilities. OT treatment fully restores social recognition. Here we demonstrate that OT acts in the medial amygdala during the initial exposure to facilitate social recognition. OT given before, but not after, the initial encounter restores social recognition in OT knock-out mice. Using c-Fos immunoreactivity (Fos-IR) as a marker of neuronal activation in this initial encounter, we found similar neuronal activation in the wild-type (WT) and OT knock-out mouse in olfactory bulbs, piriform cortex, cortical amygdala, and the lateral septum. Wild-type, but not OT knock-out mice exhibited an induction of Fos-IR in the medial amygdala. Projections sites of the medial amygdala also failed to show a Fos-IR induction in the OT knock-out mice. OT knock-out, but not WT, mice showed dramatic increases in Fos-IR in the somatosensory cortex and the hippocampus, suggesting alternative processing of social cues in these animals. With site-specific injections of OT and an OT antagonist, we demonstrate that OT receptor activation in the medial amygdala is both necessary and sufficient for social recognition in the mouse.

Facilitation of affiliation and pair-bond formation by vasopressin receptor gene transfer into the ventral forebrain of a monogamous vole

Behaviors associated with monogamy, including pair-bond formation, are facilitated by the neuropeptide vasopressin and are prevented by a vasopressin receptor [V1a receptor (V1aR)] antagonist in the male prairie vole. The neuroanatomical distribution of V1aR dramatically differs between monogamous and nonmonogamous species. V1aR binding is denser in the ventral pallidal region of several unrelated monogamous species compared with nonmonogamous species. Because the ventral pallidum is involved in reinforcement and addiction, we hypothesize that V1aR activation in this region promotes pair-bond formation via a mechanism similar to conditioning. Using an adeno-associated viral vector to deliver the V1aR gene, we increased the density of V1aR binding in the ventral pallial region of male prairie voles. These males exhibited increased levels of both anxiety and affiliative behavior compared with control males. In addition, males overexpressing the V1aR in the ventral pallidal region, but not control males, formed strong partner preferences after an overnight cohabitation, without mating, with a female. These data demonstrate a role for ventral pallidal V1aR in affiliation and social attachment and provide a potential molecular mechanism for species differences in social organization.

Prevalence of gastrointestinal symptoms associated with diabetes mellitus: a population-based survey of 15,000 adults

BACKGROUND

Gastrointestinal symptoms are reportedly common in diabetes, but a causal link is controversial and adequate population control data are lacking.

OBJECTIVE

To determine whether gastrointestinal symptoms are more frequent in persons with diabetes, particularly in those with poor glycemic control.

METHODS

Fifteen thousand adults were mailed a questionnaire (response rate, 60.0%) containing validated questions on the frequency of troublesome gastrointestinal symptoms within the past 3 months, diabetic status, and self-reported glycemic control. The prevalence of 16 symptoms and 5 symptom complexes, reported to occur often or very often, was compared using logistic regression analysis, adjusting for age and sex.

RESULTS

Overall, 8657 eligible subjects responded; 423 (4.9%) reported having diabetes. Most (94.8%) had type 2 diabetes mellitus. Adjusting for age and sex, all 16 symptoms and the 5 symptom complexes were significantly more frequent in subjects with diabetes compared with controls. An increased prevalence rate of symptoms was significantly associated with poorer levels of glycemic control but not with duration of diabetes or type of diabetic treatment.

CONCLUSIONS

Diabetes mellitus is associated with an increased prevalence of upper and lower gastrointestinal symptoms. This effect may be linked to poor glycemic control but not to duration of diabetes or type of treatment.

Cellular mechanisms of social attachment

Pharmacological studies in prairie voles have suggested that the neuropeptides oxytocin and vasopressin play important roles in behaviors associated with monogamy, including affiliation, paternal care, and pair bonding. Our laboratory has investigated the cellular and neuroendocrine mechanisms by which these peptides influence affiliative behavior and social attachment in prairie voles. Monogamous prairie voles have a higher density of oxytocin receptors in the nucleus accumbens than do nonmonogamous vole species; blockade of these receptors by site-specific injection of antagonist in the female prairie vole prevents partner preference formation. Prairie voles also have a higher density of vasopressin receptors in the ventral pallidal area, which is the major output of the nucleus accumbens, than montane voles. Both the nucleus accumbens and ventral pallidum are key relay nuclei in the brain circuits implicated in reward, such as the mesolimbic dopamine and opioid systems. Therefore, we hypothesize that oxytocin and vasopressin may be facilitating affiliation and social attachment in monogamous species by modulating these reward pathways.

Soy isoflavone supplements antagonize reproductive behavior and estrogen receptor alpha- and beta-dependent gene expression in the brain

Epidemiological evidence suggests that isoflavone phytoestrogens may reduce the risk of cancer, osteoporosis, and heart disease, effects at least partially mediated by estrogen receptors alpha and beta (ERalpha and ERbeta). Because isoflavone dietary supplements are becoming increasingly popular and are frequently advertised as natural alternatives to estrogen replacement therapy, we have examined the effects of one of these supplements on estrogen-dependent behavior and ERalpha- and ERbeta-dependent gene expression in the brain. In the adult female rat brain, 17beta-estradiol treatment decreased ERbeta messenger RNA signal in the paraventricular nucleus by 41%, but supplement treatment resulted in a 27% increase. The regulation of ERbeta in the paraventricular nucleus is probably via an ERbeta-dependent mechanism. Similarly, in the ventromedial nucleus of the hypothalamus, supplement treatment diminished the estrogen-dependent up-regulation of oxytocin receptor by 10.5%. The regulation of oxytocin receptor expression in the ventromedial nucleus of the hypothalamus is via an ERalpha-dependent mechanism. Supplement treatment also resulted in a significant decrease in receptive behavior in estrogen- and progesterone-primed females. The observed disruption of sexual receptivity by the isoflavone supplement is probably due to antiestrogenic effects observed in the brain. These results suggest that isoflavone phytoestrogens are antiestrogenic on both ERalpha- and ERbeta-dependent gene expression in the brain and estrogen-dependent behavior.

Low socioeconomic class is a risk factor for upper and lower gastrointestinal symptoms: a population based study in 15 000 Australian adults

BACKGROUND

The association of social class with health has been extensively studied, yet relationships between social class and gastrointestinal symptoms remain almost unexplored.

AIMS

To examine relationships between social class and gastrointestinal symptoms in a population sample.

METHODS

The prevalence of 16 troublesome gastrointestinal symptoms was determined by a postal questionnaire sent to 15 000 subjects (response rate 60%) and compared with a validated composite measure of socioeconomic status (index of relative socioeconomic disadvantage). Comparisons across social class were explored for five symptom categories (oesophageal symptoms; upper dysmotility symptoms; bowel symptoms; diarrhoea; and constipation). Results are reported as age standardised rate ratios with the most advantaged social class as the reference category.

RESULTS

There were clear trends for the prevalence rates of all gastrointestinal symptoms to increase with decreasing social class. These trends were particularly strong for the five symptom categories. Lower social class was associated with a significantly (p<0.0001) higher number of symptoms reported overall and with a higher proportion of individuals reporting 1-2 symptoms and more than five symptoms. In both sexes, the most pronounced effects for subjects in the lowest social class were found for constipation (males: rate ratio 1.83 (95% confidence intervals (CI) 1.16-2.51); females: rate ratio 1.68 (95% CI 1.31-2.04)) and upper dysmotility symptoms (males: rate ratio 1.45 (95% CI 1.02-1.88); females: rate ratio 1.35 (95% CI 1.07-1.63)). Oesophageal symptoms and diarrhoea were not associated with social class.

CONCLUSIONS

Troublesome gastrointestinal symptoms are linked to socioeconomic status with more symptoms reported by subjects in low socioeconomic classes. Low socioeconomic class should be considered a risk factor for both upper and lower gastrointestinal symptoms.

Expression and estrogen regulation of brain-derived neurotrophic factor gene and protein in the forebrain of female prairie voles

Brain-derived neurotrophic factor (BDNF) has been linked to the development, differentiation, and plasticity of the central nervous system. In the present study, we first used a highly specific affinity-purified antibody and a cRNA probe to generate a detailed mapping of BDNF immunoreactive (BDNF-ir) staining and mRNA labeling throughout the forebrain of female prairie voles. Our data revealed that (1) BDNF-ir cells were present essentially in the brain regions in which BDNF mRNA-labeled cells were found; (2) BDNF-ir fibers were distributed extensively throughout many forebrain regions; and (3) BDNF mRNA was also detected in some thalamic regions in which BDNF-ir fibers, but not immunostained cells, were present. With few exceptions, the distribution pattern of BDNF in the vole brain generally resembled the pattern found in rats. In a second experiment, we examined the effects of estrogen on BDNF expression. Ovariectomized prairie voles that were treated with estradiol benzoate had a higher level of BDNF mRNA labeling in the dentate gyrus and CA3 region of the hippocampus, as well as in the basolateral nucleus of the amygdala, than did ovariectomized voles that were treated with vehicle. In addition, estrogen treatment increased the density of BDNF-ir fibers in the lateral septum, dorsolateral area of the bed nucleus of the stria terminalis, and lateral habenular nucleus. These data suggest that estrogen may regulate BDNF at the level of gene and protein expression, and thus, BDNF may be in a position to mediate the effects of estrogen on the brain of the prairie vole.

Helicobacter pylori infection is not associated with diabetes mellitus, nor with upper gastrointestinal symptoms in diabetes mellitus

OBJECTIVE

The association between Helicobacter pylori (H. pylori) infection and diabetes mellitus is controversial. We aimed to determine the prevalence of H. pylori infection in patients with diabetes and nondiabetic controls, and assess whether H. pylori infection was associated with upper gastrointestinal (GI) symptoms in diabetes mellitus.

METHODS

A total of 429 patients with type 1 (n = 49) or type 2 (n = 380) diabetes mellitus (48.6% women, mean age 60.7 yr) and 170 nondiabetic controls (34.7% women, mean age 60.4 yr) were evaluated. All subjects completed a validated questionnaire (the Diabetes Bowel Symptom Questionnaire) to determine upper GI symptoms, and a blood sample was tested for H. pylori infection using a validated ELISA kit (sensitivity 96%, specificity 94%).

RESULTS

Seroprevalence of H. pylori was 33% and 32%, respectively, in patients with diabetes and controls (NS). In both groups, the seroprevalence was significantly higher in men than in women; 39% vs 25% (p = 0.002) in diabetic patients, and 40% vs 20% (p = 0.01) in controls. Patients with diabetes had a significantly higher prevalence of early satiety (OR = 2.30), fullness (OR = 3.15), and bloating (OR = 1.50) compared with controls. Upper GI symptoms were present in 49% of H. pylori-positive and 53% of H. pylori-negative patients with diabetes (OR = 0.87, 95% CI 0.58-1.31, p = 0.56). H. pylori infection was also not associated with any of the individual upper GI symptoms before or after adjustment for potential confounding factors. However, patient age and female gender were identified as independent risk factors for upper GI symptoms. Smoking was a risk factor for bloating and early satiety.

CONCLUSIONS

H. pylori infection appears not to be associated with diabetes mellitus or upper GI symptoms in diabetes mellitus.

The effects of peptides on partner preference formation are predicted by habitat in prairie voles

This study tested the hypothesis that intraspecific variations in mating systems are correlated with differences in the capacity of peripheral arginine vasopressin (AVP) to facilitate partner preferences. It has been hypothesized that differences in environmental conditions, Kansas being more xeric than Illinois, are responsible for some of the intraspecific differences in the mating systems between Kansas (KN) and Illinois (IL) prairie voles. We predicted that prairie voles from KN would be more behaviorally sensitive to peripheral AVP than prairie voles from IL. To test this hypothesis 60- to 120-day-old male and female, lab-reared, prairie voles originating from KN and IL received three subcutaneous injections of AVP or isotonic saline. Animals were then placed with an adult member of the opposite sex, designated a "partner," for a 1-hour period of cohabitation and subsequently tested for preference for the familiar partner versus a comparable stranger. Only KN males treated with AVP displayed a significant preference for the partner. Using the same experimental paradigm we also examined the ability of peripheral oxytocin (OT) to facilitate partner preference in KN prairie voles. OT facilitated partner preference in females, but not males. This finding was consistent with previous results describing the effects of peripheral OT in IL prairie voles. We also examined the hypothesis that the differential response of KN and IL males would be associated with differences in the distribution of AVP (V1a) receptors. However, there was no apparent difference in the distribution of V(1a) receptors between KN and IL males. The results of this study indicate that there is both intraspecific and intersexual variation in the regulation of social behavior in prairie voles. In addition, these findings suggest that the proximate causes of intraspecific variation may be predicted by knowledge of the habitat of origin.

The neurobiology of attachment

It is difficult to think of any behavioural process that is more intrinsically important to us than attachment. Feeding, sleeping and locomotion are all necessary for survival, but humans are, as Baruch Spinoza famously noted, "a social animal" and it is our social attachments that we live for. Over the past decade, studies in a range of vertebrates, including humans, have begun to address the neural basis of attachment at a molecular, cellular and systems level. This review describes some of the important insights from this work.

Oxytocin and vasopressin as candidate genes for psychiatric disorders: lessons from animal models

Multiple approaches should be taken to investigate the genetic bases of psychiatric disorders, including the consideration of candidate genes. Studies in animal models suggest that the genes encoding oxytocin, vasopressin, and their respective receptors should be considered in a candidate gene approach for psychiatric disorders involving social deficits, such as autism or social phobias. These neuropeptide hormones may mediate the rewarding nature of social interactions and have been implicated in social attachment and social recognition in several animal models. Mutations in genes unrelated to oxytocin and vasopressin have been shown to have secondary effects on neuropeptide function and subsequent behavioral phenotypes. Genetic analysis of polymorphisms and expression analysis of candidate genes implicated in animal models may prove useful for determining the molecular mechanisms underlying psychiatric disorders, particularly in cases where other techniques proven difficult.

Neuropeptides and the evolution of social behavior

Comparative studies over the past year have revealed two new insights into the role of neuropeptides in the evolution of social behaviors. First, across vertebrate taxa, certain neuropeptide effects appear to be gender-specific. Second, species variations in receptor gene structure can alter neuropeptide receptor distribution and thereby contribute to species differences in social behavior.

Vasopressin (V1a) receptor binding, mRNA expression and transcriptional regulation by androgen in the Syrian hamster brain

Arginine vasopressin plays an important role in the regulation of social behaviours in rodents. In the Syrian hamster, vasopressin injected directly into the brain stimulates scent marking and aggressive behaviour in a steroid dependent manner and is therefore a useful model for investigating steroid-peptide-behaviour interactions. In this study, we used in situ hybridization and radioligand binding assays on adjacent sections of hamster brains to compare the relative distribution of vasopressin (V1a) receptor mRNA and V1a receptor binding. V1a receptor mRNA and binding are abundant in the lateral septum, bed nucleus of the stria terminalis, medial preoptic nucleus, anterodorsal thalamus and suprachiasmatic nucleus. Moderate receptor binding and low levels of receptor mRNA are present in the central nucleus of the amygdala and a lateral zone from the medial preoptic area through the anterior hypothalamus. V1a receptor mRNA is anatomically more restricted in several areas compared to the ligand binding pattern, which is consistent with significant spread of receptor protein along neuronal processes. Comparison of V1a receptor ligand binding and mRNA in intact, castrated, and castrated-testosterone treated animals reveals that V1a receptors in the medial preoptic nucleus are regulated by androgen, most likely by an upregulation of V1a receptor gene expression in a cluster of neurones concentrated in the ventromedial part of this nucleus. This study confirms the presence of the V1a subtype of vasopressin receptors in behaviourally important regions of the hamster brain and suggests that transcriptional regulation by gonadal steroids may play a role in modulating behavioural sensitivity to vasopressin.