Functional networks activated by controllable and uncontrollable stress in male and female rats.

The ability of an individual to reduce the intensity, duration or frequency of a stressor is a critical determinant of the consequences of that stressor on physiology and behavior. To expand our understanding of the brain networks engaged during controllable and uncontrollable stress and to identify sex differences, we used functional connectivity analyses of the immediate early gene product Fos in male and female rats exposed to either controllable or uncontrollable tail shocks. Twenty-eight regions of interest (ROI) were selected from the structures previously evinced to be responsible for stress response, action-outcome learning, or sexual dimorphism. We found that connectivity across these structures was strongest in female rats without control while weaker connectivity was evident in male rats with control over stress. Interestingly, this pattern correlates with known behavioral sex differences where stressor controllability leads to resilience in male but not female rats. Graph theoretical analysis identified several structures important to networks under specific conditions. In sum, the findings suggest that control over stress reshapes functional connectivity.

Monoacylglycerol lipase alpha inhibition alters prefrontal cortex excitability and blunts the consequences of traumatic stress in rat.

Neural activity within the ventromedial prefrontal cortex (vmPFC) is a critical determinant of stressor-induced anxiety. Pharmacological activation of the vmPFC during stress protects against stress-induced social anxiety suggesting that altering the excitatory/inhibitory (E/I) tone in the vmPFC may promote stress resilience. E/I balance is maintained, in part, by endogenous cannabinoid (eCB) signaling with the calcium dependent retrograde release of 2-arachidonoylglycerol (2-AG) suppressing presynaptic neurotransmitter release. We hypothesized that raising 2-AG levels, via inhibition of its degradation enzyme monoacylglycerol lipase (MAGL) with KML29, would shift vmPFC E/I balance and promote resilience. In acute slice experiments, bath application of KML29 (100 nM) augmented evoked excitatory neurotransmission as evidenced by a left-shift in fEPSP I/O curve, and decreased sIPSC amplitude. In whole-cell recordings, KML29 increased resting membrane potential but reduced the after depolarization, bursting rate, membrane time constant and slow after hyperpolarization. Intra-vmPFC administration of KML29 (200ng/0.5µL/hemisphere) prior to inescapable stress (IS) exposure (25, 5s tail shocks) prevented stress induced anxiety as measured by juvenile social exploration 24 h after stressor exposure. Conversely, systemic administration of KML29 (40 mg/kg, i.p.) 2 h before IS exacerbated stress induced anxiety. MAGL inhibition in the vmPFC may promote resilience by augmenting the output of neurons that project to brainstem and limbic structures that mediate stress responses.

Ion channels, ion channel receptors, and visceral hypersensitivity in irritable bowel syndrome.

Ion channels are expressed throughout the gastrointestinal system and regulate nearly every aspect of digestion, including fluid secretion and absorption, motility, and visceral sensitivity. It is therefore not surprising that in the setting of functional bowel disorders, such as irritable bowel syndrome (IBS), ion channels are often altered in terms of expression level and function and are a target of pharmacological intervention. This is particularly true of their role in driving abdominal pain through visceral hypersensitivity (VH), which is the main reason IBS patients seek medical care. In the study by Scanzi et al., in the current issue of this journal, they provide evidence that the T-type voltage-gated calcium channel (Cav ) Cav 3.2 is upregulated in human IBS patients, and is necessary for the induction of an IBS-like disease state in mice. In this mini-review, we will discuss the contribution of specific ion channels to VH in IBS, both in human patients and rodent models. We will also discuss how Cav 3.2 may play a role as an integrator of multiple environmental stimuli contributing toward VH.

Vaginal hypersensitivity and hypothalamic-pituitary-adrenal axis dysfunction as a result of neonatal maternal separation in female mice.

Early life stress can permanently alter functioning of the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the stress response and influences the perception of pain. Chronic pelvic pain patients commonly report having experienced childhood neglect or abuse, which increases the likelihood of presenting with comorbid chronic pain and/or mood disorders. Animal models of neonatal stress commonly display enhanced anxiety-like behaviors, colorectal hypersensitivity, and disruption of proper neuro-immune interactions in adulthood. Here, we tested the hypothesis that early life stress impacts vaginal sensitivity by exposing mice to neonatal maternal separation (NMS) for 3h/day during the first two (NMS14) or three (NMS21) postnatal weeks. As adults, female mice underwent vaginal balloon distension (VBD), which was also considered an acute stress. Before or after VBD, mice were assessed for anxiety-like behavior, hindpaw sensitivity, and changes in gene and protein expression related to HPA axis function and regulation. NMS21 mice displayed significantly increased vaginal sensitivity compared to naïve mice, as well as significantly reduced anxiety-like behavior at baseline, which was heightened following VBD. NMS21 mice exhibited significant thermal and mechanical hindpaw hypersensitivity at baseline and following VBD. NMS14 mice displayed no change in anxiety-like behavior and only exhibited significantly increased hindpaw mechanical and thermal sensitivity following VBD. Centrally, a significant decrease in negative regulation of the HPA axis was observed in the hypothalamus and hippocampus of NMS21 mice. Peripherally, NMS and VBD affected the expression of inflammatory mediators in the vagina and bladder. Corticotropin-releasing factor (CRF) receptor and transient receptor potential (TRP) channel protein expression was also significantly, and differentially, affected in vagina, bladder, and colon by both NMS and VBD. Together these data indicate that NMS affects both central and peripheral aspects of the HPA axis, which may drive changes in vaginal sensitivity and the development of comorbid chronic pain and mood disorders.

5-hydroxytryptamine 2C receptors in the dorsal striatum mediate stress-induced interference with negatively reinforced instrumental escape behavior.

Uncontrollable stress can interfere with instrumental learning and induce anxiety in humans and rodents. While evidence supports a role for serotonin (5-HT) and serotonin 2C receptors (5-HT(2C)R) in the behavioral consequences of uncontrollable stress, the specific sites of action are unknown. These experiments sought to delineate the role of 5-HT and 5-HT(2C)R in the dorsal striatum (DS) and the lateral/basolateral amygdala (BLA) in the expression of stress-induced instrumental escape deficits and exaggerated fear, as these structures are critical to instrumental learning and fear behaviors. Using in vivo microdialysis, we first demonstrated that prior uncontrollable, but not controllable, stress sensitizes extracellular 5-HT in the dorsal striatum, a result that parallels prior work in the BLA. Additionally, rats were implanted with bi-lateral cannula in either the DS or the BLA and exposed to uncontrollable tail shock stress. One day later, rats were injected with 5-HT(2C)R antagonist (SB242084) and fear and instrumental learning behaviors were assessed in a shuttle box. Separately, groups of non-stressed rats received an intra-DS or an intra-BLA injection of the 5-HT(2C)R agonist (CP809101) and behavior was observed. Intra-DS injections of the 5-HT(2C)R antagonist prior to fear/escape tests completely blocked the stress-induced interference with instrumental escape learning; a partial block was observed when injections were in the BLA. Antagonist administration in either region did not influence stress-induced fear behavior. In the absence of prior stress, intra-DS administration of the 5-HT(2C)R agonist was sufficient to interfere with escape behavior without enhancing fear, while intra-BLA administration of the 5-HT(2C)R agonist increased fear behavior but had no effect on escape learning. Results reveal a novel role of the 5-HT(2C)R in the DS in the expression of instrumental escape deficits produced by uncontrollable stress and demonstrate that the involvement of 5-HT(2C)R activation in stress-induced behaviors is regionally specific.

Controllable versus uncontrollable stressors bi-directionally modulate conditioned but not innate fear.

Fear conditioning and fear extinction play key roles in the development and treatment of anxiety-related disorders, yet there is little information concerning experiential variables that modulate these processes. Here we examined the impact of exposure to a stressor in a different environment on subsequent fear conditioning and extinction, and whether the degree of behavioral control that the subject has over the stressor is of importance. Rats received a session of either escapable (controllable) tail shock (ES), yoked inescapable (uncontrollable) tail shock (IS), or control treatment (home cage, HC) 7 days before fear conditioning in which a tone and foot shock were paired. Conditioning was measured 24 h later. In a second experiment rats received ES, IS or HC 24 h after contextual fear conditioning. Extinction then occurred every day beginning 7 days later until a criterion was reached. Spontaneous recovery of fear was assessed 14 days after extinction. IS potentiated fear conditioning when given before fear conditioning, and potentiated fear responding during extinction when given after conditioning. Importantly, ES potently interfered with later fear conditioning, decreased fear responding during fear extinction, and prevented spontaneous recovery of fear. Additionally, we examined if the activation of the ventral medial prefrontal cortex (mPFCv) by ES is critical for the protective effects of ES on later fear conditioning. Inactivation of the mPFCv with muscimol at the time of the initial experience with control prevented ES-induced reductions in later contextual and auditory fear conditioning. Finally, we explored if the protective effects of ES extended to an unconditioned fear stimulus, ferret odor. Unlike conditioned fear, prior ES increased the fear response to ferret odor to the same degree as did IS.

Neurotrophic modulation of myelinated cutaneous innervation and mechanical sensory loss in diabetic mice.

Human diabetic patients often lose touch and vibratory sensations, but to date, most studies on diabetes-induced sensory nerve degeneration have focused on epidermal C-fibers. Here, we explored the effects of diabetes on cutaneous myelinated fibers in relation to the behavioral responses to tactile stimuli from diabetic mice. Weekly behavioral testing began prior to streptozotocin (STZ) administration and continued until 8 weeks, at which time myelinated fiber innervation was examined in the footpad by immunohistochemistry using antiserum to neurofilament heavy chain (NF-H) and myelin basic protein (MBP). Diabetic mice developed reduced behavioral responses to non-noxious (monofilaments) and noxious (pinprick) stimuli. In addition, diabetic mice displayed a 50% reduction in NF-H-positive myelinated innervation of the dermal footpad compared with non-diabetic mice. To test whether two neurotrophins nerve growth factor (NGF) and/or neurotrophin-3 (NT-3) known to support myelinated cutaneous fibers could influence myelinated innervation, diabetic mice were treated intrathecally for 2 weeks with NGF, NT-3, NGF and NT-3. Neurotrophin-treated mice were then compared with diabetic mice treated with insulin for 2 weeks. NGF and insulin treatment both increased paw withdrawal to mechanical stimulation in diabetic mice, whereas NT-3 or a combination of NGF and NT-3 failed to alter paw withdrawal responses. Surprisingly, all treatments significantly increased myelinated innervation compared with control-treated diabetic mice, demonstrating that myelinated cutaneous fibers damaged by hyperglycemia respond to intrathecal administration of neurotrophins. Moreover, NT-3 treatment increased epidermal Merkel cell numbers associated with nerve fibers, consistent with increased numbers of NT-3-responsive slowly adapting A-fibers. These studies suggest that myelinated fiber loss may contribute as significantly as unmyelinated epidermal loss in diabetic neuropathy, and the contradiction between neurotrophin-induced increases in dermal innervation and behavior emphasizes the need for multiple approaches to accurately assess sensory improvements in diabetic neuropathy.

Transient receptor potential vanilloid 1-immunopositive neurons in the mouse are more prevalent within colon afferents compared to skin and muscle afferents.

Previous studies in our laboratories found that isolectin B(4)(IB(4))-positive polymodal nociceptors in the mouse do not express transient receptor potential vanilloid 1 (TRPV1), nor does deletion of TRPV1 compromise the ability of these afferents to detect thermal stimuli. Considering that IB(4)-positive afferents account for over 70% of cutaneous nociceptors and that 30-50% of all mouse primary afferents express TRPV1, it is highly likely that many TRPV1-positive fibers project to non-cutaneous structures. To investigate this issue, Alexa Fluor-conjugated wheat germ agglutinin (WGA) or IB(4) was injected into the nerves innervating quadriceps muscle (femoral) or hindlimb skin (saphenous) of male C57Bl/6 mice. Similarly, Alexa Fluor-conjugated cholera toxin-beta was injected subserosally into the distal colon. Spinal ganglia at the appropriate level (L2-3 for saphenous and femoral nerves; L6 for colon) were processed for TRPV1, calcitonin gene-related peptide (CGRP), neurofilament heavy chain (NHF) and IB(4) visualization and examined on a confocal microscope. Colon afferents contained the highest percentage of both TRPV1- and CGRP-positive neurons, followed by femoral (WGA) and saphenous afferents (WGA and IB(4)). In contrast, NHF staining was more prevalent among femoral afferents, followed by saphenous (WGA) and colon afferents. IB(4) binding was observed in very few colon or saphenous (WGA) afferents, with no femoral afferents binding or transporting IB(4). Considering that the largest percentages of TRPV1-positive neurons observed in this study were within visceral and muscle afferent populations (neurons that typically are not subject to noxious temperatures), these results suggest that TRPV1 may not function primarily as a temperature sensor but rather as a detector of protons, vanilloid compounds or through interactions with other membrane proteins.

Mapping genes for resistance to Leptosphaeria maculans in Brassica juncea.

Blackleg disease of crucifers, caused by the fungus Leptosphaeria maculans, is a major concern to oilseed rape producers worldwide. Brassica species containing the B genome have high levels of resistance to blackleg. Brassica juncea F2 and first-backcross (B1) populations segregating for resistance to a PG2 isolate of L. maculans were created. Segregation for resistance to L. maculans in these populations suggested that resistance was controlled by two independent genes, one dominant and one recessive in nature. A map of the B. juncea genome was constructed using segregation in the F2 population of a combination of restriction fragment length polymorphism (RFLP) and microsatel lite markers. The B. juncea map consisted of 325 loci and was aligned with previous maps of the Brassica A and B genomes. The gene controlling dominant resistance to L. maculans was positioned on linkage group J13 based on segregation for resistance in the F2 population. This position was confirmed in the B1 population in which the resistance gene was definitively mapped in the interval flanked by pN199RV and sB31143F. The provisional location of the recessive gene controlling resistance to L. maculans on linkage group J18 was identified using a subset of informative F2 individuals.

Basic and clinical aspects of visceral sensation: transmission in the CNS.

Pain and discomfort are the leading cause for consultative visits to gastroenterologists. Acute pain should be considered a symptom of an underlying disease, thereby serving a physiologically important function. However, many patients experience chronic pain in the absence of potentially harmful stimuli or disorders, turning pain into the primary problem rather than a symptom. Vagal and spinal afferents both contribute to the sensory component of the gut-brain axis. Current evidence suggests that they convey different elements of the complex sensory experience. Spinal afferents play a key role in the discriminatory dimension, while vagal input primarily affects the strong emotional and autonomic reactions to noxious visceral stimuli. Drugs, surgical and non-pharmacological treatments can target these pathways and provide therapeutic options for patients with chronic visceral pain syndromes.

Do employees use report cards to assess health care provider systems?

OBJECTIVE: To investigate consumers' use of report cards that provide information on service quality and satisfaction at the provider group level. DATA SOURCES: In 1998 we conducted a telephone survey of randomly selected employees in firms aligned with the Buyers Health Care Action Group (BHCAG) in the Minneapolis-St. Paul market. STUDY DESIGN: Univariate probit models were used to determine report card utilization, perceived helpfulness of the report card, and ease of selecting a provider group. The characteristics used in the models included health status, age, gender, education, residency, job tenure, marital status, presence of dependent children, household income, and whether consumers changed provider groups. DATA COLLECTION: Our sample consists of survey responses from 996 single individuals (a response rate of 91 percent) and 913 families (a response rate of 96 percent). The survey was supplemented with data obtained directly from employers aligned with BHCAG. PRINCIPLE FINDINGS: Consumers who changed to a new provider group are more likely to use report card information and find it helpful, consumers employed in large firms are less likely to use the report card, and families who use information from their own health care experiences are less likely to find the report card helpful. In addition, individuals who changed to a new provider group are more likely to find the selection decision difficult. CONCLUSION: The findings show that health care consumers are using satisfaction and service-quality information provided by their employers.

How do urban organized health care delivery systems link with rural providers?

Organized delivery systems are becoming an increasingly important component of urban health care markets and are expanding their influence in rural areas as well. They also are developing new linkages with rural providers. This article, based on the experiences of 20 diverse organizations, identifies and describes the strategies being used by urban systems to redefine linkages with rural hospitals and, particularly, physicians.

Do consumers use information to choose a health-care provider system?

This study examines the use of information by employees in the Buyers Health Care Action Group, a purchasing coalition of large employers in Minneapolis. BHCAG employers contract directly with multiple health-care provider systems and attempt to inform employees about those choices. Shortly after the close of the 1998 open-enrollment period, a survey of 927 BHCAG employees with single-coverage health insurance was conducted. Seventy-six percent of the employees relied on information from their employer when selecting their current care system. Use of information from the employer was positively related to education and years of residence in the Twin Cities. Previous experience with doctors and hospitals in the care system also was a common information source. Older and low-income workers were more likely to use information from advertisements. The survey results suggest that employers can predict which information sources their employees will use.

Outcomes for Medicaid beneficiaries with schizophrenia under a prepaid mental health carve-out.

This study examines the impact of a mental health carve-out program in Utah on mental health status of Medicaid beneficiaries with schizophrenia. Three community mental health centers contracted to provide mental health care for all Medicaid beneficiaries in their service areas under managed care arrangements, while beneficiaries in the remainder of the state remained under traditional Medicaid. A pre-post evaluation was utilized, with a contemporaneous control group of Utah Medicaid beneficiaries with schizophrenia under traditional Medicaid. From 1991 to 1994, the average beneficiary's mental health status improved, but the improvement was less under the carve-out program than under traditional fee-for-service Medicaid. The difference was the greatest for beneficiaries with the worst mental health status at baseline, with effects growing over time. Medicaid beneficiaries with schizophrenia experienced less improvement in mental health status under a carve-out arrangement for mental health care compared to what would have happened under traditional Medicaid.

Performance failure of an evidence-based upper respiratory infection clinical guideline.

BACKGROUND: We evaluated an upper respiratory infection (URI) clinical guideline to determine if it would favorably affect the quality and cost of care in a health maintenance organization. METHODS: Patients with URI symptoms contacting 4 primary care practices before and after guideline implementation were compared to ascertain what proportion of all patients with respiratory symptoms were eligible for treatment in accordance with the URI guideline; what proportion of eligible patients were managed without an office visit; and what proportion of eligible patients were treated with antibiotics, before and after guideline implementation. RESULTS: A total of 3163 patients with respiratory symptoms were identified. Of these, 59% (n = 1880) had disqualifying symptoms or comorbid conditions for URI guideline care, and 28% (n = 1290) received disqualifying diagnoses on the day of first contact, leaving 13% (n = 408) who received a diagnosis of URI and were eligible for care in accordance with the guideline. Among this group of patients, the proportion who received guideline-recommended initial telephone care was 45% preguideline and 47% postguideline (chi2 = 0.40; P = .82). Likelihood of a subsequent office visit increased from pre- to postguideline (chi2 = 17.1; P <.01), although the majority of patients had no further diagnoses other than URI. Antibiotic use for the initial URI diagnosis declined from 24% preguideline to 16% postguideline (chi2 = 3.97; P = .046), but antibiotic use during 21-day follow-up did not change (F = 0.46, P = .66). The mean cost of initial care was $37.80 preguideline and $36.20 postguideline (P >.05). CONCLUSIONS: Only 13% of primary care patients with respiratory symptoms were eligible for URI guideline care. Among eligible patients, use of the guideline failed to decrease clinic visits, decrease antibiotic use during a 21-day period, or reduce cost of care to the health plan.

The financial impact on community mental health centers of capitated contracts with Medicaid: the Utah Prepaid Mental Health Plan.

Under the Utah Prepaid Mental Health Plan, three of the eleven Community Mental Health Centers in Utah signed capitation contracts with the state Medicaid program. The capitated Centers initially accepted the risk for inpatient care, with the risk later being extended to also include outpatient services. This study contrasts the financial experiences of the capitated Centers and five noncontracting Centers. While various patterns of financial management are evident in the data, it appears that the decision to contract had, at worst, a neutral effect on overall financial performance. Managed care programs with different designs may have different results.

HMO consolidations: how national mergers affect local markets.

The health maintenance organization (HMO) industry has undergone a wave of national consolidations in recent years. The most notable among these were between United HealthCare and MetraHealth (1995), PacifiCare Health Systems and FHP International (1996), Aetna Life and Casualty and U.S. Healthcare (1996), and Aetna and Prudential's health care unit (1999). This paper examines HMO consolidation from 1994 to 1997, looking first at concentration at the national level and then at the consequences of national consolidations for local markets. Whereas earlier mergers may have caused only a small increase in the type of local market concentration that may increase prices, later and currently proposed mergers may be motivated by considerations of increasing local market concentration. However, the concentration-increasing effect of national mergers was offset by the concentration-decreasing effect of HMO entry and growth. The analyses suggest that antitrust policy still has a role to play in ensuring that HMO markets remain open to new entry and in evaluating the effect of national mergers on local market concentration.

Unsedated transnasal esophagogastroduodenoscopy: a view of the future.

Unsedated transnasal esophagogastroduodenoscopy (EGD) is a unique approach to viewing the gastrointestinal tract. A significant portion of the expense and complications of conventional EGD is related to the use of conscious sedation. Transnasal EGD can be performed with a topical anesthetic alone and can be safely executed in inpatient and outpatient settings.

Patterns of outpatient use of mental health services for Medicaid beneficiaries under a prepaid mental health carve-out.

This study examines the impact of a mental health carve-out, the Utah Prepaid Mental Health Plan (UPMHP), on use of outpatient mental health services by Medicaid beneficiaries with schizophrenia. Data were collected through interviews with the same group of Medicaid schizophrenic beneficiaries. A pre/post comparison with a contemporaneous control group examined the impact of the program on type of outpatient services used by beneficiaries. The results indicate a greater reliance on medically-oriented outpatient mental health services in treatment of beneficiaries under the UPMHP. Medicaid beneficiaries with schizophrenia in the UPMHP group received relatively fewer day treatment visits, but relatively more medication visits and individual therapy visits over the first 3 1/2 years of the program.