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Objective: Electronic medical records (EMR) may increase the safety and efficiency of healthcare. Anesthesia care is a significant component of the perioperative period, yet little is known about the adoption of anesthesia information management systems (AIMS) by US anesthesiologists, particularly in non-academic settings. Herein, we report the results of a survey of US anesthesiologists regarding adoption of AIMS and anesthesiologist-perceived advantages and barriers to AIMS adoption.Methods: Using the e-mail database of the American Society of Anesthesiologists, we solicited randomly selected US anesthesiologists to participate in a survey of their AIMS adoption, perceived advantages and barriers to AIMS. Two and then 3 weeks after the initial mailing, a follow-up e-mail was sent to each anesthesiologist. The study was closed 4 weeks after the initial mailing.Results: Five thousand anesthesiologists were solicited; 615 (12.3%) responses were received. Twenty-four percent of respondents had installed an AIMS, while 13% were either installing a system now or had selected one, and an additional 13% were actively searching. Larger anesthesiology groups with large case loads, urban settings, and government affiliated or academic institutions were more likely to have adopted AIMS. Initial cost was the most frequently cited AIMS barrier. The most commonly cited benefit was more accurate clinical documentation (79%), while unanticipated need for ongoing information technology support (49%) and difficult integration of AIMS with an existing EMR (61%) were the most commonly cited problems. There were no barriers cited significantly more often by non-adopters than adopters.Conclusions: At least 50% of our survey respondents were currently using, installing, planning to install, or searching for an AIMS. However, the strength of any conclusion is undermined by a low survey response rate and potential bias as respondents using or searching for an AIMS may be more likely to participate. Nonetheless, challenges exist for anesthesiologists considering AIMS adoption including cost. Furthermore, important questions remain regarding payment for anesthesia services and the relationship of AIMS and "meaningful use" as defined by the Centers for Medicare & Medicaid Services. [ABSTRACT FROM AUTHOR]

We audited the analgesic, anti-emetic and anti-spasmodic drug usage of patients undergoing high-dose-rate brachytherapy for prostate cancer at the Royal Prince Alfred Hospital. With institutional ethics committee approval, we retrospectively reviewed the records of the first 45 patients undergoing high-dose-rate prostate brachytherapy from January 2003 to July 2005. We collected data regarding the dose of intra- and postoperative analgesics and the anti-emetic and anti-spasmodic drugs administered for the duration of the patients' hospital stay. We converted oral oxycodone doses to parenteral morphine equivalents for the purposes of this study, dividing the oxycodone dose by three. The median age of the patients was 69 (range 55 to 80) years. All had general anaesthesia for the catheter insertion procedure. Twenty-five patients (56%) received intraoperative morphine from 5 to 12 mg (mean 9 mg). Forty-three patients (96%) received regular postoperative paracetamol (1 g qid). Thirty-six patients (80%) required additional postoperative opioid administration with an overall mean (all 45 patients included) of 14.5 mg of parenteral morphine equivalents over the entire postoperative course. Thirty-nine patients received intraoperative hyoscine butylbromide to reduce bladder spasm. Fourteen patients were administered antiemetics. These findings indicate that analgesic requirements during the period in which the prostate brachytherapy catheters remained in place were minimal in most cases. Simple analgesic regimens (regular oral paracetamol, antispasmodics as required for bladder spasm and oral/subcutaneous opioids as required) appear to have been adequate for our patients. [ABSTRACT FROM AUTHOR]

Abstract Background Prognostic assessment tools to identify subgroups of patients at risk of persistent low back pain who may benefit from targeted treatments have been developed and validated in primary care. The IMPaCT Back study is investigating the effects of introducing and supporting a subgrouping for targeted treatment system in primary care. Methods/Design A prospective, population-based, quality improvement study in one Primary Care Trust in England with a before and after design. Phases 1 and 3 collect data on current practice, attitudes and behaviour of health care practitioners, patients' outcomes and health care costs. Phase 2 introduces and supports the subgrouping for targeted treatment system, via a multi-component, quality improvement intervention that includes educational courses and outreach visits led by opinion leaders, audit/feedback, mentoring and organisational support to embed the subgrouping tools within IT and clinical management systems. We aim to recruit 1000 low back pain patients aged 18 years and over consulting 7 GP practices within one Primary Care Trust in England, UK. The study includes GPs in participating practices and physiotherapists in associated services. The primary objective is to determine the effect of the subgrouping for targeted treatment system on back pain related disability and catastrophising at 2 and 6 months, comparing data from phase 1 with phase 3. Key secondary objectives are to determine the impact on: a) GPs' and physiotherapists' attitudes and behaviour regarding low back pain; b) The process of care that patients receive; c) The cost-effectiveness and sustainability of the new clinical system. Discussion This paper details the rationale, design, methods, planned analysis and operational aspects of the IMPaCT Back study. We aim to determine whether the new subgrouping for targeted treatment system is implemented and sustained in primary care, and evaluate its impact on clinical decision-making, patient outcomes and costs. Study registration International Standard Randomised Controlled Trial Number Register ISRCTN55174281

The majority of viruses classified as pandemic threats are enveloped viruses which enter the cell through receptor-mediated endocytosis and take advantage of endosomal acidification to activate their fusion machinery. Here we report that the endosomal fusion of low pH-requiring viruses is highly dependent on TRPM7, a widely expressed TRP channel that is located on the plasma membrane and in intracellular vesicles. Using several viral infection systems expressing the envelope glycoproteins of various viruses, we find that loss of TRPM7 protects cells from infection by Lassa, LCMV, Ebola, Influenza, MERS, SARS-CoV-1, and SARS-CoV-2. TRPM7 ion channel activity is intrinsically necessary to acidify virus-laden endosomes but is expendable for several other endosomal acidification pathways. We propose a model wherein TRPM7 ion channel activity provides a countercurrent of cations from endosomal lumen to cytosol necessary to sustain the pumping of protons into these virus-laden endosomes. This study demonstrates the possibility of developing a broad-spectrum, TRPM7-targeting antiviral drug to subvert the endosomal fusion of low pH-dependent enveloped viruses., (© 2024. The Author(s).)

Optic neuritis (ON) is a debilitating condition that through various mechanisms, including inflammation or demyelination of the optic nerve, can result in partial or total permanent vision loss if left untreated. Accurate diagnosis and promptly initiated treatment are imperative related to the potential of permanent loss of vision if left untreated, which can lead to a significant reduction in the quality of life in affected patients. ON is subtyped as "typical" or "atypical" based on underlying causative etiology. The etiology of ON can be differentiated when appropriate diagnostic testing is performed. Using history taking, neuroimaging, and visual testing to localize the underlying pathology of ON in a time-sensitive manner is critical in mitigating these unsatisfactory outcomes. Herein, we examine the differences in presentation, pathophysiology, and treatments of typical ON causes, like multiple sclerosis (MS), and atypical causes such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) ON. The present investigation places focus on both neuroimaging and visual imaging in the differentiation of ON. Additionally, this review presents physicians with a better understanding of different presentations, treatments, and prognoses of ON., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Spillers et al.)

Insulin secretion depends on the Ca 2+ -regulated fusion of granules with the plasma membrane. A recent model of Ca 2+ -triggered exocytosis in secretory cells proposes that lipids in the plasma membrane couple the calcium sensor Syt1 to the membrane fusion machinery (Kiessling et al. , 2018). Specifically, Ca 2+ -mediated binding of Syt1's C2 domains to the cell membrane shifts the membrane-anchored SNARE syntaxin-1a to a more fusogenic conformation, straightening its juxtamembrane linker. To test this model in live cells and extend it to insulin secretion, we enriched INS1 cells with a panel of lipids with different acyl chain compositions. Fluorescence lifetime measurements demonstrate that cells with more disordered membranes show an increase in fusion efficiency, and vice versa. Experiments with granules purified from INS1 cells and recombinant SNARE proteins reconstituted in supported membranes confirmed that lipid acyl chain composition determines SNARE conformation and that lipid disordering correlates with increased fusion. Addition of Syt1's C2AB domains significantly decreased lipid order in target membranes and increased SNARE-mediated fusion probability. Strikingly, Syt's action on both fusion and lipid order could be partially bypassed by artificially increasing unsaturated phosphatidylserines in the target membrane. Thus, plasma membrane lipids actively participate in coupling Ca 2+ /synaptotagmin-sensing to the SNARE fusion machinery in cells.

TRPM7, a TRP channel with ion conductance and kinase activities, has emerged as an attractive drug target for immunomodulation. Reverse genetics and cell biological studies have already established a key role for TRPM7 in the inflammatory activation of macrophages. Advancing TRPM7 as a viable molecular target for immunomodulation requires selective TRPM7 inhibitors with in vivo tolerability and efficacy. Such inhibitors have the potential to interdict inflammatory cascades mediated by systemic and tissue-specialized macrophages. FTY720, an FDA-approved drug for multiple sclerosis inhibits TRPM7. However, FTY720 is a prodrug and its metabolite, FTY720-phosphate, is a potent agonist of sphingosine-1-phosphate (S1P) receptors. In this study, we test non-phosphorylatable FTY720 analogs, which are inert against S1PRs and well tolerated in vivo, for activity against TRPM7 and tissue bioavailability. Using patch clamp electrophysiology, we show that VPC01091.4 and AAL-149 block TRPM7 current at low micromolar concentrations. In culture, they act directly on macrophages to blunt LPS-induced inflammatory cytokine expression, though this likely occurrs through multiple molecular targets. We found that VPC01091.4 has significant and rapid accumulation in the brain and lungs, along with direct anti-inflammatory action on alveolar macrophages and microglia. Finally, using a mouse model of endotoxemia, we show VPC01091.4 to be an efficacious anti-inflammatory agent that arrests systemic inflammation in vivo. Together, these findings identify novel small molecule inhibitors that allow TRPM7 channel inhibition independent of S1P receptor targeting which demonstrate potent, polymodal anti-inflammatory activities ex vivo and in vivo., (© 2023 Busey et al.)

Variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) challenge currently available coronavirus disease 2019 vaccines and monoclonal antibody therapies through epitope change on the receptor binding domain of the viral spike glycoprotein. Hence, there is a specific urgent need for alternative antivirals that target processes less likely to be affected by mutation, such as the membrane fusion step of viral entry into the host cell. One such antiviral class includes peptide inhibitors, which block formation of the so-called heptad repeat 1 and 2 (HR1HR2) six-helix bundle of the SARS-CoV-2 spike (S) protein and thus interfere with viral membrane fusion. We performed structural studies of the HR1HR2 bundle, revealing an extended, well-folded N-terminal region of HR2 that interacts with the HR1 triple helix. Based on this structure, we designed an extended HR2 peptide that achieves single-digit nanomolar inhibition of SARS-CoV-2 in cell-based and virus-based assays without the need for modifications such as lipidation or chemical stapling. The peptide also strongly inhibits all major SARS-CoV-2 variants to date. This extended peptide is ∼100-fold more potent than all previously published short, unmodified HR2 peptides, and it has a very long inhibition lifetime after washout in virus infection assays, suggesting that it targets a prehairpin intermediate of the SARS-CoV-2 S protein. Together, these results suggest that regions outside the HR2 helical region may offer new opportunities for potent peptide-derived therapeutics for SARS-CoV-2 and its variants, and even more distantly related viruses, and provide further support for the prehairpin intermediate of the S protein.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cell entry starts with membrane attachment and ends with spike (S) protein-catalyzed membrane fusion depending on two cleavage steps, namely, one usually by furin in producing cells and the second by TMPRSS2 on target cells. Endosomal cathepsins can carry out both. Using real-time three-dimensional single-virion tracking, we show that fusion and genome penetration require virion exposure to an acidic milieu of pH 6.2 to 6.8, even when furin and TMPRSS2 cleavages have occurred. We detect the sequential steps of S1-fragment dissociation, fusion, and content release from the cell surface in TMPRRS2-overexpressing cells only when exposed to acidic pH. We define a key role of an acidic environment for successful infection, found in endosomal compartments and at the surface of TMPRSS2-expressing cells in the acidic milieu of the nasal cavity.

Efficient clearance of apoptotic cells by phagocytosis, also known as efferocytosis, is fundamental to developmental biology, organ physiology, and immunology. Macrophages use multiple mechanisms to detect and engulf apoptotic cells, but the signaling pathways that regulate the digestion of the apoptotic cell cargo, such as the dynamic Ca 2+ signals, are poorly understood. Using an siRNA screen, we identify TRPM7 as a Ca 2+ -conducting ion channel essential for phagosome maturation during efferocytosis. Trpm7-targeted macrophages fail to fully acidify or digest their phagosomal cargo in the absence of TRPM7. Through perforated patch electrophysiology, we demonstrate that TRPM7 mediates a pH-activated cationic current necessary to sustain phagosomal acidification. Using mice expressing a genetically-encoded Ca 2+ sensor, we observe that phagosome maturation requires peri-phagosomal Ca 2+ -signals dependent on TRPM7. Overall, we reveal TRPM7 as a central regulator of phagosome maturation during macrophage efferocytosis., (© 2022. The Author(s).)

Background: A gender-based compensation gap among physicians is well documented. Even after adjusting for age, experience, work hours, productivity, and academic rank, the gender gap remained and widened over the course of a physician's career. This study aimed to examine if a significant gender pay gap still existed for anesthesiologists in the United States., Methods: In 2018, we surveyed 28,812 physician members of the American Society of Anesthesiologists to assess the association of compensation with gender and to identify possible causes of wage disparities. Gender was the primary variable examined in the model, and compensation by gender was the primary outcome. Compensation was defined as the amount reported as direct compensation on a W-2, 1099, or K-1, plus all voluntary salary reductions (eg, 401[k], health insurance). The survey directed respondents to include salary, bonuses, incentive payments, research stipends, honoraria, and distribution of profits to employees. Respondents had the option of providing a point estimate of their compensation or selecting a range in $50,000 increments. Potential confounding variables that could affect compensation were identified based on a scoping literature review and the consensus expertise of the authors. We fitted a generalized ordinal logistic regression with 7 ranges of compensation. For the sensitivity analyses, we used linear regressions of log-transformed compensation based on respondent point estimates and imputed values., Results: The final analytic sample consisted of 2081 observations (response rate, 7.2%). This sample represented a higher percentage of women and younger physicians compared to the demographic makeup of anesthesiologists in the United States. The adjusted odds ratio associated with gender equal to woman was an estimated 0.44 (95% confidence interval, 0.37-0.53), indicating that for a given compensation range, women had a 56% lower odds than men of being in a higher compensation range. Sensitivity analyses found the relative percentage difference in compensation for women compared to men ranged from -8.3 to -8.9. In the sensitivity analysis based on the subset of respondents (n = 1036) who provided a point estimate of compensation, the relative percentage difference (-8.3%; 95% confidence interval, -4.7 to -11.7) reflected a $32,617 lower compensation for women than men, holding other covariates at their means., Conclusions: Compensation for anesthesiologists showed a significant pay gap that was associated with gender even after adjusting for potential confounding factors, including age, hours worked, geographic practice region, practice type, position, and job selection criteria., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 International Anesthesia Research Society.)

Activation of Pannexin 1 (PANX1) ion channels causes release of intercellular signaling molecules in a variety of (patho)physiological contexts. PANX1 can be activated by G protein-coupled receptors (GPCRs), including α1-adrenergic receptors (α1-ARs), but how receptor engagement leads to channel opening remains unclear. Here, we show that GPCR-mediated PANX1 activation can occur via channel deacetylation. We find that α1-AR-mediated activation of PANX1 channels requires Gαq but is independent of phospholipase C or intracellular calcium. Instead, α1-AR-mediated PANX1 activation involves RhoA, mammalian diaphanous (mDia)-related formin, and a cytosolic lysine deacetylase activated by mDia - histone deacetylase 6. HDAC6 associates with PANX1 and activates PANX1 channels, even in excised membrane patches, suggesting direct deacetylation of PANX1. Substitution of basally-acetylated intracellular lysine residues identified on PANX1 by mass spectrometry either prevents HDAC6-mediated activation (K140/409Q) or renders the channels constitutively active (K140R). These data define a non-canonical RhoA-mDia-HDAC6 signaling pathway for GαqPCR activation of PANX1 channels and uncover lysine acetylation-deacetylation as an ion channel silencing-activation mechanism., (© 2021. The Author(s).)

Phagocytes reallocate metabolic resources to kill engulfed pathogens, but the intracellular signals that rapidly switch the immunometabolic program necessary to fuel microbial killing are not understood. We report that macrophages use a fast two-step Ca 2+ relay to meet the bioenergetic demands of phagosomal killing. Upon detection of a fungal pathogen, macrophages rapidly elevate cytosolic Ca 2+ (phase 1), and by concurrently activating the mitochondrial Ca 2+ (mCa 2+ ) uniporter (MCU), they trigger a rapid influx of Ca 2+ into the mitochondria (phase 2). mCa 2+ signaling reprograms mitochondrial metabolism, at least in part, through the activation of pyruvate dehydrogenase (PDH). Deprived of mCa 2+ signaling, Mcu -/- macrophages are deficient in phagosomal reactive oxygen species (ROS) production and defective at killing fungi. Mice lacking MCU in their myeloid cells are highly susceptible to disseminated candidiasis. In essence, this study reveals an elegant design principle that MCU-dependent Ca 2+ signaling is an electrometabolic switch to fuel phagosome killing., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Insulin secretion from β-cells is reduced at the onset of type-1 and during type-2 diabetes. Although inflammation and metabolic dysfunction of β-cells elicit secretory defects associated with type-1 or type-2 diabetes, accompanying changes to insulin granules have not been established. To address this, we performed detailed functional analyses of insulin granules purified from cells subjected to model treatments that mimic type-1 and type-2 diabetic conditions and discovered striking shifts in calcium affinities and fusion characteristics. We show that this behavior is correlated with two subpopulations of insulin granules whose relative abundance is differentially shifted depending on diabetic model condition. The two types of granules have different release characteristics, distinct lipid and protein compositions, and package different secretory contents alongside insulin. This complexity of β-cell secretory physiology establishes a direct link between granule subpopulation and type of diabetes and leads to a revised model of secretory changes in the diabetogenic process., Competing Interests: AK, VK, CD, NS, CU, ME, AW, JP, SH, WT, PS, IK, MH, BL, AK, BD, NL, AA, JC, LT No competing interests declared, (© 2020, Kreutzberger et al.)

Highly selective, positive allosteric modulators (PAMs) of the M 1 subtype of muscarinic acetylcholine receptor have emerged as an exciting new approach to potentially improve cognitive function in patients suffering from Alzheimer's disease and schizophrenia. Discovery programs have produced a structurally diverse range of M 1 receptor PAMs with distinct pharmacological properties, including different extents of agonist activity and differences in signal bias. This includes biased M 1 receptor PAMs that can potentiate coupling of the receptor to activation of phospholipase C (PLC) but not phospholipase D (PLD). However, little is known about the role of PLD in M 1 receptor signaling in native systems, and it is not clear whether biased M 1 PAMs display differences in modulating M 1 -mediated responses in native tissue. Using PLD inhibitors and PLD knockout mice, we showed that PLD was necessary for the induction of M 1 -dependent long-term depression (LTD) in the prefrontal cortex (PFC). Furthermore, biased M 1 PAMs that did not couple to PLD not only failed to potentiate orthosteric agonist-induced LTD but also blocked M 1 -dependent LTD in the PFC. In contrast, biased and nonbiased M 1 PAMs acted similarly in potentiating M 1 -dependent electrophysiological responses that were PLD independent. These findings demonstrate that PLD plays a critical role in the ability of M 1 PAMs to modulate certain central nervous system (CNS) functions and that biased M 1 PAMs function differently in brain regions implicated in cognition., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Highly selective positive allosteric modulators (PAMs) of the M 1 subtype of muscarinic acetylcholine receptor have emerged as an exciting new approach for improving cognitive function in patients suffering from Alzheimer's disease and schizophrenia. However, excessive activation of M 1 is known to induce seizure activity and have actions in the prefrontal cortex (PFC) that could impair cognitive function. We now report a series of pharmacological, electrophysiological, and behavioral studies in which we find that recently reported M 1 PAMs, PF-06764427 and MK-7622, have robust agonist activity in cell lines and agonist effects in the mouse PFC, and have the potential to overactivate the M 1 receptor and disrupt PFC function. In contrast, structurally distinct M 1 PAMs (VU0453595 and VU0550164) are devoid of agonist activity in cell lines and maintain activity dependence of M 1 activation in the PFC. Consistent with the previously reported effect of PF-06764427, the ago-PAM MK-7622 induces severe behavioral convulsions in mice. In contrast, VU0453595 does not induce behavioral convulsions at doses well above those required for maximal efficacy in enhancing cognitive function. Furthermore, in contrast to the robust efficacy of VU0453595, the ago-PAM MK-7622 failed to improve novel object recognition, a rodent assay of cognitive function. These findings suggest that in vivo cognition-enhancing efficacy of M 1 PAMs can be observed with PAMs lacking intrinsic agonist activity and that intrinsic agonist activity of M 1 PAMs may contribute to adverse effects and reduced efficacy in improving cognitive function.

In pancreatic β-cells, insulin granule membranes are enriched in cholesterol and are both recycled and newly generated. Cholesterol's role in supporting granule membrane formation and function is poorly understood. ATP binding cassette transporters ABCG1 and ABCA1 regulate intracellular cholesterol and are important for insulin secretion. RNAi inter-ference-induced depletion in cultured pancreatic β-cells shows that ABCG1 is needed to stabilize newly made insulin granules against lysosomal degradation; ABCA1 is also involved but to a lesser extent. Both transporters are also required for optimum glucose-stimulated insulin secretion, likely via complementary roles. Exogenous cholesterol addition rescues knockdown-induced granule loss (ABCG1) and reduced secretion (both transporters). Another cholesterol transport protein, oxysterol binding protein (OSBP), appears to act proximally as a source of endogenous cholesterol for granule formation. Its knockdown caused similar defective stability of young granules and glucose-stimulated insulin secretion, neither of which were rescued with exogenous cholesterol. Dual knockdowns of OSBP and ABC transporters support their serial function in supplying and concentrating cholesterol for granule formation. OSBP knockdown also decreased proinsulin synthesis consistent with a proximal endoplasmic reticulum defect. Thus, membrane cholesterol distribution contributes to insulin homeostasis at production, packaging, and export levels through the actions of OSBP and ABCs G1 and A1.

The US federal government has enacted legislation for a federal incentive program for health care providers and hospitals to implement electronic health records. The primary goal of the Meaningful Use (MU) program is to drive adoption of electronic health records nationwide and set the stage to monitor and guide efforts to improve population health and outcomes. The MU program provides incentives for the adoption and use of electronic health record technology and, in some cases, penalties for hospitals or providers not using the technology. The MU program is administrated by the Department of Health and Human Services and is divided into 3 stages that include specific reporting and compliance metrics. The rationale is that increased use of electronic health records will improve the process of delivering care at the individual level by improving the communication and allow for tracking population health and quality improvement metrics at a national level in the long run. The goal of this narrative review is to describe the MU program as it applies to anesthesiologists in the United States. This narrative review will discuss how anesthesiologists can meet the eligible provider reporting criteria of MU by applying anesthesia information management systems (AIMS) in various contexts in the United States. Subsequently, AIMS will be described in the context of MU criteria. This narrative literature review also will evaluate the evidence supporting the electronic health record technology in the operating room, including AIMS, independent of certification requirements for the electronic health record technology under MU in the United States.

This review outlines pharmacologic treatments for the behavioral symptoms associated with autism spectrum disorders (ASDs) in children, adolescents, and adults. Symptom domains include repetitive and stereotyped behaviors, irritability and aggression, hyperactivity and inattention, and social impairment. Medications covered include serotonin reuptake inhibitors (SRIs), mirtazapine, antipsychotics, psychostimulants, atomoxetine, α-2 agonists, D-cycloserine, and memantine. Overall, SRIs are less efficacious and more poorly tolerated in children with ASDs than in adults. Antipsychotics are the most efficacious drugs for the treatment of irritability in ASDs, and may be useful in the treatment of other symptoms. Psychostimulants demonstrate some benefit for the treatment of hyperactivity and inattention in individuals with ASDs, but are less efficacious and associated with more adverse effects compared with individuals with ADHD. D-cycloserine and memantine appear helpful in the treatment of social impairment, although further research is needed.

Introduction: Autistic disorder, Asperger's disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS) are pervasive developmental disorders (PDDs) frequently associated with behavioral symptoms that may require pharmacotherapy to manage., Areas Covered: Behavioral symptoms in children with autism include interfering repetitive behaviors, irritability, and hyperactivity and inattention, among others. The psychotropic medications examined in this review include: serotonin reuptake inhibitors, typical and atypical antipsychotics, medications used to treat attention-deficit/hyperactivity disorder, naltrexone, buspirone, divalproex sodium, lamotrigine, levetiracetam, memantine, mirtazapine, riluzole, pioglitazone, and topiramate., Expert Opinion: For the treatment of interfering repetitive behaviors, serotonin reuptake inhibitors demonstrate less efficacy and are more poorly tolerated in children with autism compared to adults. Antipsychotics are the most efficacious drugs for the treatment of irritability in children with autism and other PDDs. For the treatment of hyperactivity and inattention, psychostimulants demonstrate some benefit. However, they are overall less efficacious and cause more side effects in children with PDDs compared to typically developing children with attention-deficit/hyperactivity disorder. Results from double-blind, placebo-controlled trials of these agents and others for the treatment of the behavioral symptom domains described above will be discussed in this review.

Surfactant replacement is an effective therapy for neonatal respiratory distress syndrome. Full recovery from respiratory distress syndrome requires development of endogenous surfactant synthesis and metabolism. The influence of exogenous surfactant on the development of surfactant synthesis in premature lungs is not known. We hypothesized that different exogenous surfactants have different effects on the development of endogenous surfactant production in the premature lung. We treated organ cultures of d 25 fetal rabbit lung for 3 d with 100 mg/kg body weight of natural rabbit surfactant, Survanta, and Exosurf and measured their effects on the development of surfactant synthesis. Additional experiments tested how these surfactants and Curosurf affected surfactant protein (SP) SP-A, SP-B, and SP-C mRNA expression. Surfactant synthesis was measured as the incorporation of 3H-choline and 14C-glycerol into disaturated phosphatidylcholine recovered from lamellar bodies. Randomized-block ANOVA showed significant differences among treatments for incorporation of both labels (p < 0.01), with natural rabbit surfactant less than control, Survanta greater than control, and Exosurf unchanged. Additional experiments with natural rabbit surfactant alone showed no significant effects in doses up to 1000 mg/kg. Survanta stimulated disaturated phosphatidylcholine synthesis (173 +/- 41% of control; p = 0.01), increased total lamellar body disaturated phosphatidylcholine by 22% (p < 0.05), and increased 14C-disat-PC specific activity by 35% (p < 0.05). The response to Survanta was dose-dependent up to 1000 mg/kg. Survanta did not affect surfactant release. No surfactant altered the expression of mRNA for SP-A, SP-B, or SP-C. We conclude that surfactant replacement therapy can enhance the maturation of surfactant synthesis, but this potential benefit differs with different surfactant preparations.

The Drosophila eyes absent (eya) gene has a role in regulating cell death and/or differentiation and is expressed throughout development. We evaluated the transcripts and proteins encoded by one of the human homologues of Drosophila eya coined Eyes Absent 2 (EYA2). Interestingly, EYA2 was expressed in several neuroblastoma cell lines as four distinct transcripts having alternative 5'-ends, whereas only one EYA2 transcript was expressed in the normal human eye. Due to different translation start sites on the four unique transcripts, two isoforms of EYA2 protein (one previously identified and one novel) could be generated in neuroblastoma cells, but the sole EYA2 transcript expressed in the eye can only encode the novel isoform. Immunoblot analyses suggest that EYA2 may also be post-translationally modified. Finally, the alternative EYA2 transcripts have dissimilar numbers of upstream open reading frames in their 5'-untranslated regions. Therefore, in addition to encoding alternative isoforms of EYA2, regulation of EYA2 expression appears to involve both transcriptional and translational components.

Objective: To determine effects of increased dietary protein and decreased dietary carbohydrate on hematologic variables, body composition, and racing performance in Greyhounds., Animals: 8 adult Greyhounds., Procedure: Dogs were fed a high-protein (HP; 37% metabolizable-energy [ME] protein, 33% ME fat, 30% ME carbohydrate) or moderate-protein (MP; 24% ME protein, 33% ME fat, 43% ME carbohydrate) extruded diet for 11 weeks. Dogs subsequently were fed the other diet for 11 weeks (crossover design). Dogs raced a distance of 500 m twice weekly. Rectal temperature, hematologic variables before and after racing, plasma volume, total body water, body weight, average weekly food intake, and race times were measured at the end of each diet period., Results: When dogs were fed the MP diet, compared with the HP diet, values (mean +/- SD) differed significantly for race time (32.43 +/- 0.48 vs 32.61 +/- 0.50 seconds), body weight (32.8 +/- 2.5 vs 32.2 +/- 2.9 kg), Hct before (56 +/- 4 vs 54 +/- 6%) and after (67 +/- 3 vs 64 +/- 8%) racing, and glucose (131 +/- 16 vs 151 +/- 27 mg/dl) and triglyceride (128 +/- 17 vs 104 +/- 28 mg/dl) concentrations after racing., Conclusions and Clinical Relevance: Greyhounds were 0.18 seconds slower (equivalent to 0.08 m/s or 2.6 m) over a distance of 500 m when fed a diet with increased protein and decreased carbohydrate. Improved performance attributed to feeding meat to racing Greyhounds apparently is not attributable to increased dietary protein and decreased dietary carbohydrate.

This study represents the first time that both the mobile phase composition and the temperature are simultaneously controlled to examine silica-bonded octadecylsilyl (C18) ligands spectroscopically at typical liquid chromatographic (LC) mobile phase flow-rates and back-pressures. Raman spectroscopy is used to characterize the behavior of the C18 bonded ligands equilibrated at temperatures from 45 to 2 degrees C in neat, single-component, mobile phase solvents including: water, acetonitrile, methanol, and chloroform. In addition, the effect of stationary phase ligand bonding density is examined by using two different monomeric reversed-phase liquid chromatographic (RPLC) stationary phases, a 2.34 and a 3.52 micromol m(-2) Microporasil C18 stationary phase, under identical conditions. The direct, on-column, spectroscopic analysis used in this study allows direct evaluation of the temperature-dependent behavior of the bonded C18 ligands. The temperature-dependent ordering of the stationary phase ligands is examined to determine if the ligands undergo a phase transition from a less-ordered "liquid-like" state at higher temperatures to a more-ordered "solid-like" state at lower temperatures. A discrete phase transition was not observed, but rather a continual ordering as temperature was lowered.

Raman spectroscopy is used to examine the effect of mobile phase composition on the orientation of octadecyl-bonded silica-based reversed-phase liquid chromatographic (RPLC) stationary phase ligands. The effect of ligand bonding density is also investigated. The present experimental set-up utilizes a direct, noninvasive, on-column approach to examine the solvent dependent conformational behavior of the bonded ligands under flow-rate and back pressure conditions similar to those used during conventional RPLC measurements. Neat, single-component, mobile phase solvents including water, acetonitrile, methanol and chloroform are used to investigate the hypothesized collapsing and extension of stationary phase ligands with changes in mobile phase composition. No evidence of phase collapse was observed upon changing the mobile phase composition from an organic to an aqueous content. Also, Raman spectroscopic measurements allowed the differentiation between associated and free acetonitrile solvent.

The substance P receptor neurokinin-1 is expressed by a subset of neurons in the rat spinal cord. We have combined immunostaining for Fos, a marker of noxious peripheral stimulation, and neurokinin-1 to examine whether nociceptive signals from particular peripheral tissues (skin, muscle or knee joint) or activity generated by nerve injury or formalin-induced inflammation are preferentially modulated by substance P. Our results indicate that superficial and deep spinal neurokinin-1-positive neurons process nociceptive information in markedly different ways. In lamina I, the number of double-labelled neurons was positively correlated with the intensity of the stimulus (defined by the total Fos count) and was not directly related to any particular peripheral target. However, in the deeper layers of the spinal cord (V-X), there was no such correlation, and stimulation of joint nociceptors and formalin-induced inflammation produced the greatest proportion of Fos/neurokinin-1 co-localization, suggesting a particular role for substance P in the mediation of joint pain and inflammatory hyperalgesia. Thus, lamina I neurokinin-1 receptor-bearing neurons appear to be involved in intensity discriminative aspects of pain, whereas the deep neurokinin-1 cells are involved in spatial localization or the detection of particular nociceptive submodalities.

The current study investigated the effect of erbium filtration on an anteroposterior abdominal image. The radiation dose reductions achievable and the cost effectiveness of this filter were also evaluated. An assessment of the radiation dose delivered employing either the standard total filtration (3 mm Al equivalent) or 0.1 mm of erbium filtration added to the standard filtration was undertaken on 21 patients. Image quality was assessed using the Commission of European Communities (CEC) criteria. Significant reductions of 64.6 % in entrance surface (p = 0.0001) and 23.4 % in effective dose (p = 0.0099) were recorded with erbium filtration. Image quality was maintained and the cost per man saved was pound 128. More widespread use of this dose reducing filter is advocated.

Lamina I neurons of the spinal cord convey specific nociceptive activity to the brain. A subpopulation of lamina I cells bears substance P receptors (neurokinin-1) and recent studies have shown that these neurons encode for the intensity of noxious peripheral stimulation. Here, we report that cool thermal stimuli, applied to the hindpaw of anaesthetized rats, induce Fos expression in lamina I neurokinin-1 neurons that is graded with respect to the intensity of the thermal stimulus. Thus, as the temperature of the stimulus was reduced, both the total number of neurokinin-l-positive neurons expressing Fos and the proportion of Fos nuclei present within neurokinin-1 cells showed a significant increase. These data show that lamina I neurokinin-1 cells encode the intensity of noxious cooling of the skin. In laminae III and IV, although there was no correlation between neurokinin-1 cell activation and stimulus intensity, the total Fos count in these layers was inversely related to the depth of cooling. Thus, neurons in laminae III and IV may also play a role in thermoreception.

Sensory neurons in neonatal rat lumbar dorsal root ganglia die after sciatic nerve axotomy, and previous studies have estimated the total cell loss to be 40-95%. We have used the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) technique, combined with immunohistochemistry, to investigate the contribution of apoptosis to the cell loss that occurs after unilaterally transecting the sciatic nerve of new-born rats. TUNEL-positive cells were detected 1 day post-lesion, and their number peaked 3 days after the injury. Combining TUNEL labelling with immunohistochemistry, for neuron-specific neurofilament 150 kDa, or glial-specific S-100beta, enabled us to identify dying neurons and dying glia. One day after axotomy, most of the TUNEL-positive cells (58%) were neurons, whereas 3 days post-injury, only a small number of dying cells (6%) were neuronal. This lower incidence was due to a decrease in neuronal death and an increase in glial death. The glia in the dorsal root ganglia therefore die subsequent to the neurons. The apoptotic nature of the cell death was confirmed by electron microscopy, with fine structural features of apoptotic cell death, e.g. chromatin compaction and membrane blebbing, being observed in both glia and neurons. Our results confirm that extensive apoptosis occurs in the neonatal lumbar dorsal root ganglia after sciatic nerve section, and show that neurons and glial cells die with different time-courses. The results suggest a neuron-glia trophic interdependence in the dorsal root ganglia.

The peptide neurotransmitter substance P modulates sensitivity to pain by activating the neurokinin-1 (NK-1) receptor, which is expressed by discrete populations of neurons throughout the central nervous system. Substance P is synthesized by small-diameter sensory 'pain' fibres, and release of the peptide into the dorsal horn of the spinal cord following intense peripheral stimulation promotes central hyperexcitability and increased sensitivity to pain. However, despite the availability of specific NK-1 antagonists, the function of substance P in the perception of pain remains unclear. Here we investigate the effect of disrupting the gene encoding the NK-1 receptor in mice. We found that the mutant mice were healthy and fertile, but the characteristic amplification ('wind up') and intensity coding of nociceptive reflexes was absent. Although substance P did not mediate the signalling of acute pain or hyperalgesia, it was essential for the full development of stress-induced analgesia and for an aggressive response to territorial challenge, demonstrating that the peptide plays an unexpected role in the adaptive response to stress.

This study investigated the neurodevelopmental basis of schizophrenia by examining an early transient population of serotonin-1A (5-HT1A) receptors using quantitative [3H]8-OH-DPAT autoradiography on sections of frozen postmortem cerebellum. Production of an ontogenetic map showed that human neonatal cerebellum acquired dense 5-HT1A receptors, most of which were eliminated by early childhood. Autoradiographic measurements on cerebellar vermis from 16 control adult subjects confirmed sparse 5-HT1A receptor binding. The data show a persistence of some vermal 5-HT1A receptors in brains from 19 adults with chronic schizophrenia in whom there may have been a slowed or arrested postnatal regression of vermal 5-HT1A receptors. Alternatively, some 5-HT1A receptors may have been re-expressed prior to, or subsequent to, the onset of the disease symptoms. The findings are not obviously explained by drug treatment and there are no data to explain how neuroleptics might promote expression of cerebellar 5-HT1A receptors. We propose that the study has identified a neurotransmitter receptor population which, in schizophrenia, undergoes misdirected reshaping during brain development. The findings support neurodevelopmental hypotheses of the disease.

Human rhinovirus (HRV) accounts for a significant portion of common-cold illness, with the peak incidence being in the early fall. Three hundred forty-six adults who had self-diagnosed colds of 48 h or less were enrolled in a study during September and October 1994 to determine the frequency and clinical course of HRV infections. Nasal wash specimens for viral culture and reverse transcription-PCR (RT-PCR) for HRV RNA and human coronavirus OC43 and 229E RNA detection were collected on enrollment, and participants recorded their symptoms twice daily for 14 days. Middle ear pressure (MEP) was measured with a digital tympanometer on days 1 and 7. Picornaviruses (224 HRV and 7 enterovirus isolates) were detected by culture in 67% (231 of 346) of the subjects. Among 114 samples negative by culture, HRV was detected by RT-PCR in 52 (46%) for an overall picornavirus infection rate of 82% (283 of 346 subjects). Among the remaining 62 negative samples, human coronavirus RNA was detected by RT-PCR in 5 patients, so that 288 (83%) of patients had documented viral infection. The first symptom noticed most often was sore throat (40%) in HRV culture- or PCR-positive patients and stuffy nose in HRV-negative patients (27%). No differences in symptom scores over time or in the presence of individual symptoms were noted between groups. The median duration of the cold episodes was 11 days in HRV culture-positive patients, 9.5 days in HRV RT-PCR-positive patients, and 11.5 days in HRV-negative patients. On enrollment, abnormal MEPs (< or = -100 or > or = +100 mm of H2O) were found for 21% of HRV culture-positive patients, 14% of HRV RT-PCR-positive patients, and 10% of HRV-negative patients. No important differences in the clinical course of HRV culture-positive, HRV culture-negative and RT-PCR-positive, or HRV-negative colds were found. These results represent the highest frequency of virologically confirmed natural colds to date and document the importance of rhinoviruses as the cause of colds during fall months.

Amphiphysin (Amph) is a src homology 3 domain-containing protein that has been implicated in synaptic vesicle endocytosis as a result of its interaction with dynamin. In a screen for novel members of the amphiphysin family, we identified Amph2, an isoform 49% identical to the previously characterized Amph1 protein. The subcellular distribution of this isoform parallels Amph1, both being enriched in nerve terminals. Like Amph1, a role in endocytosis at the nerve terminal is supported by the rapid dephosphorylation of Amph2 on depolarization. Importantly, the two isoforms can be coimmunoprecipitated from the brain as an equimolar complex, suggesting that the two isoforms act in concert. As determined by cross-linking of brain extracts, the Amph1-Amph2 complex is a 220- to 250-kDa heterodimer. COS cells transfected with either Amph1 or Amph2 show greatly reduced transferrin uptake, but coexpression of the two proteins rescues this defect, supporting a role for the heterodimer in clathrin-mediated endocytosis. Although the src homology 3 domains of both isoforms interact with dynamin, the heterodimer can associate with multiple dynamin molecules in vitro and activates dynamin's GTPase activity. We propose that it is an amphiphysin heterodimer that drives the recruitment of dynamin to clathrin-coated pits in endocytosing nerve terminals.

The activated form (p65) of nuclear factor kappa B (NF-kappa B) was found to be expressed in a sub-population (32%) of mixed diameter rat sensory neurons in L4 and L5 dorsal root ganglia, indicating that this transcription factor is involved in intracellular signalling in sensory neurons under physiological conditions. Four hours after crushing the sciatic nerve, ipsilateral p65 staining was abolished in a subgroup (60-70%) of these neurons. The contralateral side was unaffected by the injury and loss of NF-kappa B activity was not observed following sham surgery. Within 24 h of sciatic injury, ipsilateral p65 staining had recovered to control levels. We suggest that the decline in p65 after nerve injury was due to failure of retrograde axonal transport of trophic factor(s). Since neurotrophins and cytokines promote the survival of non-neuronal cells by activation of NF-kappa B, we believe that p65 may be critical for the resistance to apoptosis shown by adult sensory neurons.

This study represents the first Raman spectroscopic characterization of conventional chemically-bonded liquid chromatographic (LC) stationary phases under typical flow-rate and pressure conditions. Raman spectra were obtained for amino propyl (NH2), cyano propyl (CN), phenyl (Ph), octadecyl (C18), octyl (C8), and methyl (C1) chemically-bonded silica-based stationary phases in 100% aqueous mobile phases. The present experimental set-up has allowed Raman spectra of various stationary phase ligands, present in sub-monolayer coverages on the siliceous supports, to be obtained. This study: (1) demonstrates that conventional Raman spectroscopic techniques can be used to study LC stationary phases; (2) presents the experimental set-up, conditions, and approaches utilized to obtain Raman spectra of conventional stationary phases; (3) examines the spectroscopic differences observed for a variety of different types of bonded ligands that are typically used in reversed-phase (RPLC) and normal-phase (NPLC) liquid chromatographic separations; and (4) considers other future studies that are possible with this experimental approach, including mobile phase composition and temperature studies.

The induction of homosynaptic long-term depression and depotentiation of previously established long-term potentiation was investigated in the CA1 hippocampal region of anaesthetized and awake adult rats following prolonged ipsilateral low-frequency stimulation of the Schaffer collateral/ commissural pathway. Prolonged low-frequency stimulation at 1-10 Hz failed to induce long-term depression of field excitatory postsynaptic potentials in the anaesthetized or awake adult rat. However, prolonged low-frequency stimulation at 5 and 10 Hz, although not at 1 or 2 Hz, did induce depotentiation of previously established long-term potentiation in anaesthetized animals. Thus, in the anaesthetized animals, 900 pulses at 10 Hz induced a depotentiation of 68%, 59% and 66% when given 10, 30 and 40 min following long-term potentiation induction. Depotentiation could also be induced at much longer times following the induction of long-term potentiation. Thus, in anaesthetized rats, depotentiation measuring 34% was induced by 10-Hz stimulation 4 h following long-term potentiation induction, and depotentiation measuring 60% was induced in two sets of experiments 24 h after long-term potentiation induction in awake animals. The results of the present study show that homosynaptic long-term depression was not induced in the adult hippocampus in vivo using stimulation protocols which are effective in hippocampal slices. However, erasure of long-term potentiation by the process of depotentiation has been shown to occur in the adult hippocampus in vivo, both at short times and at prolonged times after the induction of long-term potentiation.

The aim of the study was to use immunohistochemistry to identify, in the hippocampal region of human brain. the distribution of neuronal and endothelial isoforms of the enzyme nitric oxide synthase. Numerous pyramidal neurons and small, presumed GABAergic interneurons throughout the pyramidal cell layer of CA1-CA3 exhibited neuronal nitric oxide synthase-like immunoreactivity. Comparable immunopositive cells were seen in the granule cell and polymorphic layers of the dentate gyrus and in the stratum oriens. A dense plexus of immunopositive fibres was seen in the granule cell layer of the dentate gyrus. In contrast, endothelial nitric oxide synthase-like immunoreactivity was localized specifically, and with a pronounced punctate distribution, to the cell bodies of CA1 pyramidal neurons. The endothelial isoform was also present in blood vessels and in cells which resembled astroglia. These latter cells had a similar appearance and distribution to astroglia identified by their positive reaction to glial fibrillary acidic protein. The most frequently used method for identifying nitric oxide synthase-containing cells in brain, the NADPH-diaphorase reaction, was also applied to hippocampal sections. Only occasional NADPH-diaphorase-positive cells were seen in the hippocampus where, in contrast to their nitric oxide synthase-like immunoreactivity, the pyramidal cells did not stain for NADPH-diaphorase. Similarly, only occasional NADPH-diaphorase-reactive varicose axons were found in the hippocampus in these experiments. This study is the first to identify mostly separate populations of cells containing neuronal and endothelial nitric oxide synthase isoforms in human hippocampus. The data show that NADPH-diaphorase histochemistry, which is frequently used to show the presence of nitric oxide synthase, greatly underestimates the potential for hippocampal cells to produce nitric oxide. The fact that human hippocampus has a great many nitric oxide synthase-containing cells implies that nitric oxide has a role in human hippocampal functions although, at the present time, these actions are not clear. Whether those stimuli known to produce nitric oxide, such as activation of glutamate N-methyl-D-aspartate receptors, cause both enzyme isoforms in CA1 pyramidal cells to produce nitric oxide remains to be determined.

Brains from patients with schizophrenia have been reported to contain deficient and dysplastic forebrain neurons containing nitric oxide synthase (NOS). As part of a study of NOS in schizophrenia, we decided to investigate the cerebellum, which has particularly high levels of NOS. We used an autoradiographic method to measure the density and distribution of NOS. Sections of frozen cerebellum removed at autopsy were labelled with the selective NOS inhibitor [3H]L-NG-nitro-arginine. NOS levels were visualized in sagittal sections of vermis from 16 control subjects and 21 schizophrenia patients, and measurements were taken from the three groups of developmentally-distinct lobules I-V, VI-VII and VIII-X. The highest NOS density was in the Purkinje/molecular layer of cerebellar cortex, although there was some NOS in the granule cell layer. There were no differences in Purkinje/molecular or granule cell layer NOS levels between the two groups of subjects. The mild structural faults in cerebellar vermis observed in some patients with schizophrenia probably do not involve reductions in NOS-containing cells.

A method was developed for magnetic resonance imaging (MRI) of human autopsy brains stored long-term at -70 degrees C. Scanning brains at temperatures between -70 and -8 degrees C gave minimal MRI signals consistent with protons having limited freedom of movement at low temperature. Raising brain temperature improved the signal such that scanning at -1 degree C generated images with good in-plane resolution, grey/white matter contrast, and fine detail of cortical sulcal/gyral patterns. To validate the method, volume and area measurements were made using computerized image analysis on stored digital images of 14 brains from adult subjects of both genders and various ages. The data confirmed that brain volume was inversely correlated with age, and female subjects had smaller brains. This is a valuable new method for acquiring morphometric data from previously unscanned pathologic brains that are to be used for neurochemical and molecular investigations.

The organization of catecholamine-containing axons in the cat lateral cervical nucleus was examined by immunocytochemical methods using a specific tyrosine hydroxylase antiserum. Light microscopic examination revealed numerous tyrosine hydroxylase-immunoreactive axons and varicosities throughout this nucleus, and some of these structures were found in contact with neuronal cell bodies. Correlated ultrastructural analysis showed that these varicosities were synaptic boutons which formed symmetric synaptic junctions with dendrites and somata. This evidence suggests that catecholamines exert a postsynaptic action upon neurons within the lateral cervical nucleus.

The organization of neuropeptide Y-containing profiles in the dorsal horn of cat lumbosacral spinal cord was examined in an immunocytochemical study employing a specific antiserum against neuropeptide Y. Light-microscopic inspection revealed heavy concentrations of immunoreactive axons and varicosities within the superficial layers of the dorsal horn (laminae I and II) and only low to moderate numbers of positive terminals in the deeper layers (laminae III-VI). Neuropeptide-Y immunoreactivity in the superficial laminae occurred primarily as single punctate terminals, although in sagittal sections long rostrocaudally orientated fibres were also found. Immunoreactive fibres in the deeper layers were usually long and beaded. Two-hundred and eight neuropeptide Y-immunoreactive profiles throughout laminae I-VI were examined through serial sections with the electron microscope, and the overwhelming majority (n = 194) was confirmed to be axon terminals, most of which (95%) formed synaptic junctions. These terminals were packed with small irregularly shaped agranular vesicles, together with a number of large dense-core vesicles. Immunoreactivity was homogeneously scattered throughout the cytoplasm, and was also associated with the dense-core vesicles. A few neuropeptide Y-containing profiles (n = 14) were difficult to classify but they could have been vesicle-containing dendrites. The postsynaptic targets of neuropeptide Y-positive terminals were similar throughout each dorsal horn lamina. Most frequently, neuropeptide Y-positive boutons formed axodendritic and axosomatic synaptic junctions (range = 64% of synapses in laminae V/VI to 83% in lamina III). A smaller proportion of synapses were found upon other axon terminals and in laminae I-III the postsynaptic axon terminals were sometimes the central boutons of glomeruli. A number of terminals, especially those in lamina II, formed multiple synapses which often comprised a triadic arrangement. These findings suggest that neuropeptide Y regulates spinal sensory transmission through both a postsynaptic action upon dorsal horn neurons and a presynaptic action upon primary afferent terminals.

Lumbosacral (L6-S1) spinal cord neurons in the cat were retrogradely labelled after uptake of horseradish peroxidase by their severed axons in the upper cervical (C3-C4) dorsolateral funiculus. Sections of L6-S1 containing labelled neurons were then processed immunocytochemically using antibodies against dopamine-beta-hydroxylase or tyrosine hydroxylase, two enzymes responsible for the synthesis of catecholamines. Two hundred and ninety eight retrogradely-labelled cells within laminae III-V of the dorsal horn were examined under high power (x 1000) with the light microscope. In Triton X-100-treated material, only 13% of these cells had catecholamine-containing varicosities closely apposed to their somata and proximal dendrites, which suggests that in comparison with the postsynaptic dorsal column pathway, spinocervical tract neurons are only sparsely innervated by descending catecholaminergic axons.

Previous ultrastructural studies have shown that catecholamine-containing nerve terminals in the spinal dorsal horn form synaptic junctions with dendrites and somata, but the identity of the neurons giving rise to these structures is largely unknown. In this study we have investigated the possibility that spinomedullary neurons, which project through the dorsal columns to the dorsal column nuclei, are synaptic targets for descending catecholaminergic axons. Neurons with axons ascending the dorsal columns were retrogradely labelled after uptake of horseradish peroxidase by their severed axons in the thoracic (T10-T12) or cervical (C2-C3) dorsal columns. After the retrogradely labelled neurons were visualized, the tissue was immunocytochemically stained with antisera raised against tyrosine hydroxylase or dopamine-beta-hydroxylase. Three hundred forty-three retrogradely labelled neurons within laminae III-V of the lumbosacral dorsal horn were examined under high power with the light microscope. In Triton X-100 treated material, over 60% of cells were found to have dopamine-beta-hydroxylase-immunoreactive varicosities closely apposed to their somata and proximal dendrites. The number of contacts per cell varied from 1 to 22, with a mean number of 4.5. Fewer cells (34%) received contacts from axons immunoreactive for tyrosine hydroxylase as a consequence of the weaker immunoreaction produced by this antiserum. Correlated light and electron microscopic analysis confirmed that many of these contacts were regions of synaptic specialization and that immunostained boutons contained pleomorphic (round to oval) agranular vesicles together with several dense core vesicles. These observations suggest that catecholamines regulate sensory transmission through this spinomedullary pathway by a direct postsynaptic action upon its cells of origin. Such an action would be predicted to suppress transmission generally through this pathway.

The ultrastructural organization of nerve terminals containing neuropeptide Y-immunoreactivity was studied in the substantia gelatinosa of the cat spinal dorsal horn. Seventy immunoreactive boutons were examined through serial sections and 67 of them were found to form between one and five synaptic junctions with dendrites (59.5% of synapses), somata (3% of synapses) and other axon terminals (37.5% of synapses). The postsynaptic axon terminals were often the central boutons of glomeruli. These findings suggest that neuropeptide Y regulates spinal sensory transmission through both a postsynaptic action upon dorsal horn neurons and a presynaptic action upon primary afferent terminals.