Search

Adenosine is a putative sleep factor with effects mainly mediated by the A1 receptor. Recent studies have implicated the hypothalamic orexin/hypocretin-containing neurons in the control of sleep–wakefulness. To help determine if adenosine might play a role in the control of orexin neurons, immunohistochemistry was used to characterize the distribution of adenosine A1 receptor protein on the orexinergic neurons. About 30% of orexin-containing neurons were labeled. The data supports the presence of adenosine A1 receptors on orexinergic neurons and suggests a possible substrate for a functional role of adenosine in the regulation of orexinergic activity. [Copyright &y& Elsevier]

Recent experiments suggest that brainstem GABAergic neurons may control rapid-eye-movement (REM) sleep. However, understanding their pharmacology/physiology has been hindered by difficulty in identification. Here we report that mice expressing green fluorescent protein (GFP) under the control of the GAD67 promoter (GAD67-GFP knock-in mice) exhibit numerous GFP-positive neurons in the central gray and reticular formation, allowing on-line identification in vitro. Small (10–15 µm) or medium-sized (15–25 µm) GFP-positive perikarya surrounded larger serotonergic, noradrenergic, cholinergic and reticular neurons, and > 96% of neurons were double-labeled for GFP and GABA, confirming that GFP-positive neurons are GABAergic. Whole-cell recordings in brainstem regions important for promoting REM sleep [subcoeruleus (SubC) or pontine nucleus oralis (PnO) regions] revealed that GFP-positive neurons were spontaneously active at 3–12 Hz, fired tonically, and possessed a medium-sized depolarizing sag during hyperpolarizing steps. Many neurons also exhibited a small, low-threshold calcium spike. GFP-positive neurons were tested with pharmacological agents known to promote (carbachol) or inhibit (orexin A) REM sleep. SubC GFP-positive neurons were excited by the cholinergic agonist carbachol, whereas those in the PnO were either inhibited or excited. GFP-positive neurons in both areas were excited by orexins/hypocretins. These data are congruent with the hypothesis that carbachol-inhibited GABAergic PnO neurons project to, and inhibit, REM-on SubC reticular neurons during waking, whereas carbachol-excited SubC and PnO GABAergic neurons are involved in silencing locus coeruleus and dorsal raphe aminergic neurons during REM sleep. Orexinergic suppression of REM during waking is probably mediated in part via excitation of acetylcholine-inhibited GABAergic neurons. [ABSTRACT FROM AUTHOR]

Short interfering RNAs (siRNA) targeting prepro-orexin mRNA were microinjected into the rat perifornical hypothalamus. Prepro-orexin siRNA-treated rats had a significant (59%) reduction in prepro-orexin mRNA compared to scrambled siRNA-treated rats 2 days postinjection, whereas prodynorphin mRNA was unaffected. The number of orexin-A-positive neurons on the siRNA-treated side decreased significantly (23%) as compared to the contralateral control (scrambled siRNA-treated) side. Neither the colocalized dynorphin nor the neighbouring melanin-concentrating hormone neurons were affected. The number of orexin-A-positive neurons on the siRNA-treated side did not differ from the number on the control side 4 or 6 days postinjection. Behaviourally, there was a persistent (∼ 60%) increase in the amount of time spent in rapid eye movement (REM) sleep during the dark (active) period for 4 nights postinjection, in rats treated with prepro-orexin siRNA bilaterally. This increase occurred mainly because of an increased number of REM episodes and decrease in REM-to-REM interval. Cataplexy-like episodes were also observed in some of these animals. Wakefulness and NREM sleep were unaffected. The siRNA-induced increase in REM sleep during the dark cycle reverted to control values on the 5th day postinjection. In contrast, the scrambled siRNA-treated animals only had a transient increase in REM sleep for the first postinjection night. Our results indicate that siRNA can be usefully employed in behavioural studies to complement other loss-of-function approaches. Moreover, these data suggest that the orexin system plays a role in the diurnal gating of REM sleep. [ABSTRACT FROM AUTHOR]

The basal forebrain (BF) is involved in arousal, attention, and reward processing but the role of individual BF neuronal subtypes is still being uncovered. Glutamatergic neurons are the least well-understood of the three main BF neurotransmitter phenotypes. Here we analyzed the distribution, size, calcium-binding protein content and projections of the major group of BF glutamatergic neurons expressing the vesicular glutamate transporter subtype 2 (vGluT2) and tested the functional effect of activating them. Mice expressing Cre recombinase under the control of the vGluT2 promoter were crossed with a reporter strain expressing the red fluorescent protein, tdTomato, to generate vGluT2-cre-tdTomato mice. Immunohistochemical staining for choline acetyltransferase and a cross with mice expressing green fluorescent protein selectively in GABAergic neurons confirmed that cholinergic, GABAergic and vGluT2+ neurons represent distinct BF subpopulations. Subsets of BF vGluT2+ neurons expressed the calcium-binding proteins calbindin or calretinin, suggesting that multiple subtypes of BF vGluT2+ neurons exist. Anterograde tracing using adeno-associated viral vectors expressing channelrhodopsin2-enhanced yellow fluorescent fusion proteins revealed major projections of BF vGluT2+ neurons to neighboring BF cholinergic and parvalbumin neurons, as well as to extra-BF areas involved in the control of arousal or aversive/rewarding behavior such as the lateral habenula and ventral tegmental area. Optogenetic activation of BF vGluT2+ neurons elicited a striking avoidance of the area where stimulation was given, whereas stimulation of BF parvalbumin or cholinergic neurons did not. Together with previous optogenetic findings suggesting an arousal-promoting role, our findings suggest that BF vGluT2 neurons play a dual role in promoting wakefulness and avoidance behavior. [ABSTRACT FROM AUTHOR]

The basal forebrain (BF) plays an important role in the control of cortical activation and attention. Understanding the modulation of BF neuronal activity is a prerequisite to treat disorders of cortical activation involving BF dysfunction, such as Alzheimer's disease. Here we reveal the interaction between cholinergic neurons and cortically projecting BF GABAergic neurons using immunohistochemistry and whole-cell recordings in vitro. In GAD67-GFP knock-in mice, BF cholinergic (choline acetyltransferase-positive) neurons were intermingled with GABAergic (GFP+) neurons. Immunohistochemistry for the vesicular acetylcholine transporter showed that cholinergic fibers apposed putative cortically projecting GABAergic neurons containing parvalbumin (PV). In coronal BF slices from GAD67-GFP knock-in or PV-td Tomato mice, pharmacological activation of cholinergic receptors with bath application of carbachol increased the firing rate of large (>20 μm diameter) BF GFP+ and PV (tdTomato) neurons, which exhibited the intrinsic membrane properties of cortically projecting neurons. The excitatory effect of carbachol was blocked by antagonists of M1 and M3 muscarinic receptors in two subpopulations of BF GABAergic neurons [large hyperpolarization-activated cation current (Ih ) and small Ih, respectively]. Ion substitution experiments and reversal potential measurements suggested that the carbachol-induced inward current was mediated mainly by sodium-permeable cation channels. Carbachol also increased the frequency of spontaneous excitatory and inhibitory synaptic currents. Furthermore, optogenetic stimulation of cholinergic neurons/fibers caused a mecamylamine- and atropine-sensitive inward current in putative GABAergic neurons. Thus, cortically projecting, BF GABAergic/PV neurons are excited by neighboring BF and/or brainstem cholinergic neurons. Loss of cholinergic neurons in Alzheimer's disease may impair cortical activation, in part, through disfacilitation of BF cortically projecting GABAergic/PV neurons. [ABSTRACT FROM AUTHOR]

The basal forebrain (BF) strongly regulates cortical activation, sleep homeostasis, and attention. Many BF neurons involved in these processes are GABAergic, including a subpopulation of projection neurons containing the calcium-binding protein, parvalbumin (PV). However, technical difficulties in identification have prevented a precise mapping of the distribution of GABAergic and GABA/PV+ neurons in the mouse or a determination of their intrinsic membrane properties. Here we used mice expressing fluorescent proteins in GABAergic (GAD67-GFP knock-in mice) or PV+ neurons (PV-Tomato mice) to study these neurons. Immunohistochemical staining for GABA in GAD67-GFP mice confirmed that GFP selectively labeled BF GABAergic neurons. GFP+ neurons and fibers were distributed throughout the BF, with the highest density in the magnocellular preoptic area (MCPO). Immunohistochemistry for PV indicated that the majority of PV+ neurons in the BF were large (>20 μm) or medium-sized (15-20 μm) GFP+ neurons. Most medium and large-sized BF GFP+ neurons, including those retrogradely labeled from the neocortex, were fast-firing and spontaneously active in vitro. They exhibited prominent hyperpolarization-activated inward currents and subthreshold 'spikelets,' suggestive of electrical coupling. PV+ neurons recorded in PV-Tomato mice had similar properties but had significantly narrower action potentials and a higher maximal firing frequency. Another population of smaller GFP+ neurons had properties similar to striatal projection neurons. The fast firing and electrical coupling of BF GABA/PV+ neurons, together with their projections to cortical interneurons and the thalamic reticular nucleus, suggest a strong and synchronous control of the neocortical fast rhythms typical of wakefulness and REM sleep. J. Comp. Neurol., 521:1225-1250, 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives: The National Cardiovascular Data Registry (NCDR) developed the Data Quality Program to meet the objectives of ensuring the completeness, consistency, and accuracy of data submitted to the observational clinical registries. The Data Quality Program consists of 3 main components: 1) a data quality report; 2) a set of internal quality assurance protocols; and 3) a yearly data audit program. Background: Since its inception in 1997, the NCDR has been the basis for the development of performance and quality metrics, site-level quality improvement programs, and peer-reviewed health outcomes research. Methods: Before inclusion in the registry, data are filtered through the registry-specific algorithms that require predetermined levels of completeness and consistency for submitted data fields as part of the data quality report. Internal quality assurance protocols enforce data standards before reporting. Within each registry, 300 to 625 records are audited annually in 25 randomly identified sites (i.e., 12 to 25 records per audited site). Results: In the 2010 audits, the participant average raw accuracy of data abstraction for the CathPCI Registry, ICD Registry, and ACTION Registry-GWTG were, respectively, 93.1% (range, 89.4% minimum, 97.4% maximum), 91.2% (range, 83.7% minimum, 95.7% maximum), and 89.7.% (range, 85% minimum, 95% maximum). Conclusions: The 2010 audits provided evidence that many fields in the NCDR accurately represent the data from the medical charts. The American College of Cardiology Foundation is undertaking a series of initiatives aimed at creating a quality assurance rapid learning system, which, when complete, will monitor, evaluate, and improve data quality. [ABSTRACT FROM AUTHOR]

The locus coeruleus (LC) regulates sleep/wakefulness and is densely innervated by orexinergic neurons in the lateral hypothalamus. Here we used small interfering RNAs (siRNAs) to test the role of LC orexin type 1 receptor (OxR1) in sleep-wake control. In sleep studies, bilateral OxR1 siRNA injections led to an increase of time spent in rapid eye movement (REM) sleep, which was selective for the dark (active) period, peaked at approximately 30% of control during the second dark period after injection and then disappeared after 4 days. Cataplexy-like episodes were not observed. The percentage time spent in wakefulness and non-REM (NREM) sleep and the power spectral profile of NREM and REM sleep were unaffected. Control animals, injected with scrambled siRNA, had no sleep changes after injection. Quantification of the knockdown revealed that unilateral microinjection of siRNAs targeting OxR1 into the rat LC on two consecutive days induced a 45.5% reduction of OxR1 mRNA in the LC 2 days following the injections when compared with the contralateral side receiving injections of control (scrambled) siRNAs. This reduction disappeared 4 days after injection. Similarly, unilateral injection of OxR1 siRNA into the LC revealed a marked (33.5%) reduction of OxR1 staining 2 days following injections. In contrast, both the mRNA level and immunohistochemical staining for tyrosine hydroxylase were unaffected. The results indicate that a modest knockdown of OxR1 is sufficient to induce observable sleep changes. Moreover, orexin neurons, by acting on OxR1 in the LC, play a role in the diurnal gating of REM sleep. [ABSTRACT FROM AUTHOR]

Context: Quality of care of patients with acute myocardial infarction (AMI) has received intense attention. However, it is unknown if a structured initiative for improving care of patients with AMI can be effectively implemented at a wide variety of hospitals. Objective: To measure the effects of a quality improvement project on adherence to evidence-based therapies for patients with AMI. Design and Setting: The Guidelines Applied in Practice (GAP) quality improvement project, which consisted of baseline measurement, implementation of improvement strategies, and remeasurement, in 10 acute-care hospitals in southeast Michigan. Patients: A random sample of Medicare and non-Medicare patients at baseline (July 1998–June 1999; n = 735) and following intervention (September 1–December 15, 2000; n = 914) admitted at the 10 study centers for treatment of confirmed AMI. A random sample of Medicare patients at baseline (January–December 1998; n = 513) and at remeasurement (March–August 2001; n = 388) admitted to 11 hospitals that volunteered, but were not selected, served as a control group. Intervention: The GAP project consisted of a kickoff presentation; creation of customized, guideline-oriented tools designed to facilitate adherence to key quality indicators; identification and assignment of local physician and nurse opinion leaders; grand rounds site visits; and premeasurement and postmeasurement of quality indicators. Main Outcome Measures: Differences in adherence to quality indicators (use of aspirin, β-blockers, and angiotensin-converting enzyme [ACE] inhibitors at discharge; time to reperfusion; smoking cessation and diet counseling; and cholesterol assessment and treatment) in ideal patients, compared between baseline and postintervention samples and among Medicare patients in GAP hospitals and the control group. Results: Increases in adherence to key treatments were seen in the administration of aspirin (81% vs 87%; P =... [ABSTRACT FROM AUTHOR]