Noradrenergic modulatoins of odor learning and odor representation in the rat

How experience alters neuronal ensemble dynamics and how locus coeruleus-mediated norepinephrine release facilitates memory formation in the brain are the topics of this thesis. Here we employed a visualization technique, cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH), to assess activation patterns of neuronal ensembles in the olfactory bulb (OB) and anterior piriform cortex (aPC) to repeated odor inputs. Two associative learning models were used, early odor preference learning in rat pups and adult rat go-no-go odor discrimination learning. With catFISH of an immediate early gene, Arc, we showed that odor representation in the OB and aPC was sparse (~5-10%) and widely distributed. Odor associative learning enhanced the stability of the rewarded odor representation in the OB and aPC. The stable component, indexed by the overlap between the two ensembles activated by the rewarded odor at two time points, increased from ~25% to ~50% (p = 0.004-1.43E⁻4; Chapter 3 and 4). Adult odor discrimination learning promoted pattern separation between rewarded and unrewarded odor representations in the aPC. The overlap between rewarded and unrewarded odor representations reduced from ~25% to ~14% (p = 2.28E⁻⁵). However, learning an odor mixture as a rewarded odor increased the overlap of the component odor representations in the aPC from ~23% to ~44% (p = 0.010; Chapter 4). Blocking both α- and β-adrenoreceptors in the aPC prevented highly similar odor discrimination learning in adult rats, and reduced OB mitral and granule ensemble stability to the rewarded odor. Similar treatment in the OB only slowed odor discrimination learning. However, OB adrenoceptor blockade disrupted pattern separation and ensemble stability in the aPC when the rats demonstrated deficiency in discrimination (Chapter 5). In another project, the role of α₂-adrenoreceptors in the OB during early odor preference learning was studied. OB α2-adrenoceptor activation was necessary for odor learning in rat pups. α₂-adrenoceptor activation was additive with β-adrenoceptor mediated signalling to promote learning (Chapter 2). Together, these experiments suggest that odor representations are highly adaptive at the early stages of odor processing. The OB and aPC work in concert to support odor learning and top-down adrenergic input exerts a powerful modulation on both learning and odor representation.

Temperature-related differences in the calcium transient between Atlantic cod (Gadus morhua) and steelhead trout (Oncorhynchus mykiss) cardiomyocytes

The Atlantic cod, Gadus morhua, differs from many teleosts in that its heart does not respond to adrenergic stimulation, and is more capable of maintaining function during acute temperature changes. To examine if differences in intracellular calcium mobilization are associated with these atypical responses, confocal microscopy was used to study the calcium handling of cardiac cells from Atlantic cod vs. steelhead trout at their acclimation temperature (10ºC), or subjected to acute temperature changes (to 4 and 16ºC), while being stimulated across a range of frequencies (10 – 110 min⁻¹). In addition, cells were tested with and without tonic (10 nM) levels of adrenaline at 10ºC, and pharmacological blockers were used to study the relative contributions of the L-type Ca²⁺ channel, sarcoplasmic reticulum and Na+/Ca²⁺ exchanger to the Ca²⁺ transient. Consistent with previous in vitro and in situ studies, there were few significant effects of adrenaline on the Ca²⁺ transient of cod cardiomyocytes, yet adrenaline had significant positive inotropic effects on trout cardiomyocytes. At 10ºC, peak Ca²⁺ (F/F₀) only differed between the two species at low stimulation frequencies (10, 30 min-1), with trout F/F₀ 25-35% higher. In contrast, the time to peak Ca²⁺ and the time to half relaxation were both shorter (by 10 – 35% across frequencies) in cod. Acute temperature changes caused a shift in the Ca²⁺ - frequency relationship in both species, with F/F₀ values higher for trout at low frequencies (< 70 min⁻¹) at 4ºC, whereas this parameter was greater at all frequencies except 10 min⁻¹ in cod at 16ºC. Unfortunately, these experiments did not highlight clear species differences in the relative contributions of the L-type Ca²⁺ channels, sarcoplasmic reticulum and Na+/Ca²⁺ exchange to the Ca²⁺ transient.

Childhood asthma exacerbations and the Arg16 β2-receptor polymorphism : a meta-analysis stratified by treatment

Peer reviewed

Origem do plexo lombossacral e seus nervos em quatis (Nasua nasua, LINNAEUS, 1766)

The objective of this research is to study the origin of the lumbosacral plexus and its nerves in coatis (Nasua nasua). Six adult specimens, three males and three females, were used in this research. The animals were donated by IBAMA / GO or were collected when found dead by the edges of highways in Southeast Goiás. The specimens were fixed in aqueous 10% formaldehyde solution and preserved in the same solution. The observations reveal that the lumbosacral plexus of the coati has a structure with few intercommunications between its components. There are no typical handle formations, but the roots or its branches converge to form the nerves that are driven to the pelvic limb. The components of the Lumbosacral Plexus are ventral branches of L4 to S3. The Lumbosacral plexus generates several short nerves destined to pelvic structures and, at the same time, three long nerves: femoral, obturator and sciatic, all destined to the hind limb.

Données nouvelles sur les innervations cholinergiques de l'hippocampe et du néostriatum et sur leur ultrastructure au cours du développement

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Pharmacological enhancement of naltrexone treatment for opioid dependence: a review.

PURPOSE: Opioid dependence (OD) is a serious and growing clinical condition with increasing social costs that requires expanding treatment beyond opioid agonist substitution. The opioid antagonist naltrexone has displayed a remarkable association of theoretical effectiveness and poor clinical utility in treating OD due to noncompliant behavior and low acceptability among patients, only partly modified by psychosocial interventions. We reviewed pharmacological studies, including naltrexone depot formulations and combination treatments. METHOD: We searched PubMed for clinical studies on the use of naltrexone implants and slow-release injections in OD, and investigations using adjunct medications to improve naltrexone maintenance therapy of OD. We discussed the results in view of their application to the clinical practice. RESULTS: Significant reduction in opioid use and improved retention in treatment have been found in several studies using depot naltrexone formulations, some of which are controlled clinical trials. Pilot investigations have gathered initial positive results on the use of naltrexone in combination with serotonin reuptake inhibitors, α-2 adrenergic, opioid, and γ-aminobutyric acid agonist medications. CONCLUSION: Current evidence suggests that more research on effectiveness and safety is needed in support of depot naltrexone treatment for OD. Further research comparing slow-release with oral naltrexone and opioid agonist medications will help characterize the role of opioid antagonist-mediated treatment of OD. Preliminary investigations on naltrexone combination treatments suggest the opportunity to continue study of new mixed receptor activities for the treatment of OD and other drug addictions.

Extended-release ranolazine: critical evaluation of its use in stable angina.

Coronary heart disease is the major cause of morbidity and mortality throughout the world, and is responsible for approximately one of every six deaths in the US. Angina pectoris is a clinical syndrome characterized by discomfort, typically in the chest, neck, chin, or left arm, induced by physical exertion, emotional stress, or cold, and relieved by rest or nitroglycerin. The main goals of treatment of stable angina pectoris are to improve quality of life by reducing the severity and/or frequency of symptoms, to increase functional capacity, and to improve prognosis. Ranolazine is a recently developed antianginal with unique methods of action. In this paper, we review the pharmacology of ranolazine, clinical trials supporting its approval for clinical use, and studies of its quality of life benefits. We conclude that ranolazine has been shown to be a reasonable and safe option for patients who have refractory ischemic symptoms despite the use of standard medications (for example, nitrates, beta-adrenergic receptor antagonists, and calcium channel antagonists) for treatment of anginal symptoms, and also provides a modestly improved quality of life.

The impact of maternal inflammation and maternal stress in the regulation of neurodevelopment and physiological function

The mechanisms governing fetal development follow a tightly regulated pattern of progression such that interference at any one particular stage is likely to have consequences for all other stages of development in the physiological system that has been affected thereafter. These disturbances can take the form of many different events but two of the most common and widely implicated in causing detrimental effects to the developing fetus are maternal immune activation (MIA) and maternal stress. MIA has been shown to cause an increase in circulating proinflammatory cytokines in both the maternal and fetal circulation. This increase in proinflammatory mediators in the fetus is thought to occur by fetal production rather than through exchange between the maternal-fetal interface. In the case of maternal stress it is increased levels of stress related hormones such as cortisol/corticosterone which is thought to elicit the detrimental effects on fetal development. In the case of both maternal infection and stress the timing and nature of the insult generally dictates the severity and type of effects seen in affected offspring. We investigated the effect of a proinflammatory environment on neural precursor cells of which exposure resulted in a significant decrease in the normal rate of proliferation of NPCs in culture but did not have any effect on cell survival. These effects were seen to be age dependent. Using a restraint stress model we investigated the effects of prenatal stress on the development of a number of different physiological systems in the same cohort of animals. PNS animals exhibited a number of aberrant changes in cardiovascular function with altered responses to stress and hypertension, modifications in respiratory responses to hypercapnic and hypoxic challenges and discrepancies in gastrointestinal innervation. Taken together these findings suggest that both maternal infection and maternal stress are detrimental to the normal development of the fetus.

Données nouvelles sur les innervations cholinergiques de l'hippocampe et du néostriatum et sur leur ultrastructure au cours du développement

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Gut hormone GPCRs: structure, function, drug discovery

Crystallization and determination of the high resolution three-dimensional structure of the β2-adrenergic receptor in 2007 was followed by structure elucidation of a number of other receptors, including those for neurotensin and glucagon. These major advances foster the understanding of structure-activity relationship of these receptors and structure-based rational design of new ligands having more predictable activity. At present, structure determination of gut hormone receptors in complex with their ligands (natural, synthetic) and interacting signalling proteins, for example, G-proteins, arrestins, represents a challenge which promises to revolutionize gut hormone endocrinonology.

The ins of the striatum: Utilizing chemogenetics to define the contribution of cortical and thalamic afferents during addiction behaviors

Thesis (Ph.D.)--University of Washington, 2016-08

What kind of surgery for cervical carcinoma?

The incidence and mortality of cervical cancer have changed over the past 50 years in developed countries, but this kind of tumor still remains a significant clinical problem because it is the second most common cause of morbidity and mortality from cancer among women. After histological confirmation of invasive cervical cancer, the extent of disease was determined using clinical criteria to assign a stage. This assessment is important because, while for the other gynecologic cancers clinical information obtained by surgery and histopathological examination is implemented and concurs to define the staging of the disease, the cervical cancer tumor stage is given after the primary diagnosis. In this review we discuss how the surgical approach to cervical cancer has been evolved, in order to modulate the radicality of the intervention itself and thus to preserve the pelvic innervation. This step has been achieved by deepening knowledge of functional pelvic anatomy and modulating the radicality of hysterectomy according to well defined surgical landmarks.

Effects of unilateral visual deprivation on the developing avian brain

The effect of varying states of visual deprivation on the development of the optic lobes and cerebral hemispheres has been studied in the chick where the visual pathways are totally crossed over. Unilateral eye extirpation of the new hatched chick resulted in arrested development of the contralateral but not ipsilateral lobe, as measured by weight, protein content and acetylcholinesterase activity. Similar effects but of smaller magnitude were observed in the cerebral hemispheres. Histologic and enzymic evidence revealed the absence of significant degeneration in the optic lobe contralateral to an eye removed 17 days previously. These results were observed in the optic lobes of operated animals maintained either in light of in darkness between 3 and 17 days after hatch. However, in the inpaired cerebral hemispheres, differences could only be detected in birds kept the light. The effects of unilateral eyelid suturing on the development of chick brain regions were also examined. In this group, all asymmetrical differences observed within paired brain regions were totally light dependent and confined to the cerebral hemispheres. The hemisphere contralateral to the sutured eye weighed less and had less acetylcholinesterase activity than its paired hemisphere. The cerebral hemispheres of monocularly treated birds manifested effects of similar magnitude whether the treatment was enucleation or suturing. This suggests that the complete development of the associative centers in avian cerebral hemispheres is dependent on both intact innervation and on the information content of the visual input. © 1969.

Studies on the synthesis of novel PP2A inhibitors and a GPCR detergent

Chapter 1 While targeting kinases in oncology research has been explored extensively, targeting protein phosphatases is currently in its infancy. However, a number of pharmaceutical companies are currently looking to expand their research efforts in this area. PP2A has been shown to down-regulate ERK5, a mitogen-activated protein kinase (MAPK) that has been shown to be important in driving the invasive phenotype of prostate cancer. Fostriecin and its related structural analogues PD 113,270 and 113,271 have been shown to inhibit a mitotic entry checkpoint in cell growth through the potent and selective inhibition of protein phosphatases PP1, PP2A, and PP4 (IC50 of 45 μM, 1.5 nM, and 3 nM respectively). Fostriecin is one of the most selective protein phosphatase inhibitors disclosed to date with a 104 fold selectivity for PP2A/PP4 versus PP1. Unfortunately, fostriecin and its analogues are very unstable, and this instability has effectively prevented them from being used as effective therapeutic leads. The microcystins and nodularins on the other hand, exhibit significant inhibitory activity against PP1 and PP2A (IC50 = 26 pM and 1.8 nM respectively), but their high toxicity has prevented any therapeutic application. Truncation of the ADDA chain from these polypeptides completely attenuates PP inhibitory activity. Simpler analogues incorporating the N-acylated ADDA chain and D-Ala retain moderate activity against PP1 and PP2A (IC50 = 1.0 μM and 0.17 μM respectively). The generation of a new series of fostriecin analogues to further expand its structure-activity relationship is envisaged with a view to creating new more stable PP2A inhibitors. It was hoped that by incorporating some of the more stable structural features of ADDA into fostriecin that stability and activity could be reconciled. With that in mind a series of PP2A inhibitors were synthesised and biologically evaluated. Chapter 2 GPCRs are an important area of research and are the targets of a quarter of the drugs on the market (2005). As a result, GPCRs continue to be at the forefront of research in both small and large drug companies. However one of the difficulties in studying this diverse class of membrane proteins is their tendency to denature in aqueous solution. As a result there is a pressing need to develop new detergents to solubilise, stabilise and crystallise GPCRs in their native form for further study. Cholesterol analogues have been shown to be important for stabilising membrane proteins and preventing their thermal inactivation. In addition the β2-adrenergic receptor, a GPCR membrane protein, has been crystallised in the active state with two cholesterol molecules bound between the I, II, III and IV helices of the protein. This appears to represent a distinct cholesterol binding pocket on the membrane protein that is speculated to be conserved across up to 44% of the rhodopsin class of GPCRs. CHOBIMALT is a cholesterol-based detergent that has been shown to exhibit promising GPCR-stabilising properties. When benchmarked against other cholesterol based detergents it was found to be superior to all others tested except for cholesteryl hemisuccinate.1 CHOBIMALT has an aggregation number of roughly 200 and forms 210 ± 30 kDa micelles, which are significantly larger than those of most detergents used for biological systems which is likely due to the packing constraints associated with CHOBMALT’s large polar headgroup.2 As a result, CHOBIMALT is used mostly as an additive to other commercially available detergents in order to decrease micelle size. A branched dimaltoside motif is common in recently synthesised detergents by Chae and co-workers. These detergents have shown promising detergent properties, for example the maltose neopentyl glycol (MNG) detergent synthesised by Chae. This branched dimaltoside detergent was shown to be able to solubilise and stabilise the very labile light harvesting complex I (LHI) from Rhodopsin capsulatus in its active form for 20 days with little loss of protein conformation.3 A cholesterol-based detergent was envisaged that combines the cholesterol framework of CHOBIMALT but replaces its linear tetrasaccharide with a branched dimaltoside. This detergent would then be investigated to assess its ability to solubilise, stabilise and crystallise GPCR proteins. This cholesterol-based detergent (shown below) was eventually synthesised in 9 linear steps from cholesterol.

Effects of feeding carnitine and ractopamine on rainbow trout (Oncorhynchus mykiss, Walbaum 1972)

L-carnitine is required for the transfer of long-chain fatty acids from the cytosol to the mitochondrial matrix for 13-oxidation of them and ractopamine, beta adrenergic agonists, have potential stimulating lipolysis and altering rates of protein degradation and synthesis. Present study was carried out to improve lipid body oxidation and protein-sparing action of fish through addition of L-carnitine and ractopamine to diet of rainbow trout, Oncorhynchus mykiss, Walbaum 1972. An eight-week feeding trial was carried out to evaluate the effects of supplementation of tree levels of L-carnitine tartrate (0, 1 and 2 g/kg) and two levels of ractopamine hydrochloride (0 and 10 ppm) on growth performance, fillet muscle fatty acid compositions and blood biochemical parameters in 288 juvenile rainbow trout (130 g) at 3X2 factorial experimental design. Ractopamine and 1 g/kg carnitine improved the specific growth rate, feed conversion ratio, protein efficiency ratio and weight gain at the end of experiment. The protein and lipid contents of fillet muscle were affected by the inclusion of 10 mg/kg ractopamine in the diet, increasing crude protein and reducing crude fat (P<0.05) of fish fillet muscle. The highest protein and lowest fat contents of fish fillet were observed in diet that contains 2 g/kg carnitine plus ractopamine. Ractopamine and carnitine increased levels of albumin, total protein and globulin in fish blood serum, but carnitine increased triacylglycerol and cholesterol. Fatty acids compositions of fish fillet were also affected by ractopamine and carnitine. All fatty acids except for eicosapentaenoic acid and docosahexaenoic acid, were increased by dietary supplementation of ractopamine. Total saturated fatty acids were not affected by carnitine. Supplementation (P>0.05). However, total n-3 poly unsaturated fatty acids were reduced by carnitine supplementation. A significant interaction was observed between ractopamine and carnitine supplementation regarding the saturated (P<0.01) and n-3 poly unsaturated fatty acid (P<0.001) of fish fillet. This study shows that supplementation of 1 g/kg carnitine and 10 ppm ractopamine could improve performance of juvenile rainbow trout and their combination in diet results in protein increment, fat reduction and change in profile of fatty acids in fillet muscle.