Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dopamine (DA) causes a dose-dependent increase in the frequency of motor neuron bursts [virtual ventilation (fR)] produced by deafferented crab ventilatory pattern generators (CPGv). Domperidone, a D2-specific DA antagonist, by itself reversibly depresses fR and also blocks the stimulatory effects of DA. Serotonin (5HT) has no direct effects on this CPGv. Nicotine also causes dramatic dose-dependent increases in the frequency of motor bursts from the CPGv. The action is triphasic, beginning with an initial reversal of burst pattern typical of reversed-mode ventilation, followed by a 2- to 3-min period of depression and then a long period of elevated burst rate. Acetylcholine chloride (ACh) alone is ineffective, but in the presence of eserine is moderately stimulatory. The inhibitory effects of nicotine are only partially blocked by curare. The excitatory action of nicotine is blocked by prior perfusion of domperidone, but not by SKF-83566.HCl, a D1-specific DA antagonist. SKF-83566 had no effects on the ongoing pattern of firing. These observations support the hypothesis that dopaminergic pathways are involved in the maintenance of the CPGv rhythm and that the acceleratory effects of nicotine may involve release of DA either directly or via stimulation of atypical ACh receptors at intraganglionic sites.
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PMID:Dopamine and nicotine, but not serotonin, modulate the crustacean ventilatory pattern generator. 143 39

A bolus injection of almitrine bismesylate (0.5 mg.kg-1 i.v.) in anaesthetised artificially ventilated cats caused a significantly greater increase in carotid chemosensory discharge in animals with sectioned ipsilateral ganglioglomerular sympathetic nerves in comparison with a group in which these nerves were intact. Plasma levels of almitrine were similar in both groups. Responses to hypoxia and hypercapnia post-almitrine were also bigger if the ganglioglomerular nerves were cut. Domperidone (10-50 micrograms.kg-1 i.a), a dopamine D2 receptor antagonist, greatly increaed the responsiveness of chemoreceptors to almitrine in ganglioglomerular nerve-intact preparations. Almitrine-induced chemosensory activity was unaffected by illuminating the carotid bifurcation with light from a fibre optic lamp, regardless of whether or not the ganglioglomerular nerves were cut. It is concluded that almitrine may directly or indirectly activate an efferent pathway in the ganglioglomerular nerves to cause depression of chemoreceptor activity, possibly by releasing dopamine to act at D2 dopamine receptors in the carotid body.
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PMID:Ganglioglomerular nerves influence responsiveness of cat carotid body chemoreceptors to almitrine. 252 5

Dopamine levels in rat carotid bodies and the effects of intravenous dopamine injections on respiration in adult rats anaesthetized with pentobarbitone have been studied in animals which were treated with capsaicin neonatally. Levels of dopamine were five fold higher in the carotid bodies of capsaicin-treated rats as compared with vehicle-treated controls, but there was no significant difference between capsaicin-treated and vehicle-treated rats in their ID50 values for dopamine-induced respiratory depression. Domperidone, a dopamine D2-receptor antagonist, substantially reduced the respiratory depression caused by dopamine, both in capsaicin-treated and in control animals, suggesting that a D2-receptor was involved in the response. Cutting the carotid sinus nerves greatly reduced the ventilatory-depressant effect of dopamine, showing that sensory receptors, most probably arterial chemoreceptors, were responsible for most of the response. Substantially less reflex hyperventilation was evoked in capsaicin-treated rats by the peripheral chemoreceptor stimulants hypoxia and sodium cyanide, in comparison with the controls, and domperidone did not increase the responsiveness. About 80% of the reflex ventilatory change originated from carotid body chemoreceptors. The hypoventilation caused by breathing 100% O2 was not significantly different in capsaicin-treated rats when compared with controls. Domperidone substantially reduced this response in capsaicin-treated rats, but not in vehicle-treated animals. Dopamine-induced respiratory depression in capsaicin-treated rats was slightly enhanced, rather than reduced, by oxygen breathing; domperidone remained an effective antagonist of dopamine-induced ventilatory depression. Most of the reduction in respiration caused by dopamine in rats anaesthetized with pentobarbitone can be attributed to actions on a dopamine D2-receptor located in the carotid body. However, despite the increased levels of dopamine found in the carotid bodies, the reduced peripheral chemosensitivity observed in anaesthetized capsaicin-treated rats does not appear to result from a change in sensitivity to dopamine.
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PMID:Changes in carotid body amine levels and effects of dopamine on respiration in rats treated neonatally with capsaicin. 651 43

Duloxetine, (+)-N-methyl-3-(1-naphthalenyloxy)-2-thiophenepropanamine, is an inhibitor of the serotonin and norepinephrine neuronal transporters (Wong et al., 1993). In mice, duloxetine antagonized the depletion of brain serotonin by p-chloroamphetamine (ED50 = 2.5 mg/kg, i.p.) and the depletion of heart norepinephrine by 6-hydroxydopamine (ED50 = 1.1 mg/kg, i.p.). Brain concentrations of 5-hydroxyindoleacetic acid were decreased by duloxetine at 2 hr after doses of 1, 3 and 10 mg/kg and at 1 to 8 hr (but not 24 hr) after a 10 mg/kg i.p. dose of duloxetine. Duloxetine antagonized norepinephrine depletion in frontal cortex, but not dopamine depletion in striatum, after treatment of mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. In rats, duloxetine decreased brain 5-hydroxyindoleacetic acid dose-dependently for up to 8 hr and decreased serotonin turnover measured by the accumulation of 5-hydroxytryptophan in rat hypothalamus after decarboxylase inhibition. In rats, duloxetine antagonized the depletion of brain serotonin by p-chloramphetamine and the depletion of norepinephrine and epinephrine in hypothalamus after i.c.v. injection of 6-hydroxydopamine. In vitro, duloxetine had little effect on either type A (serotonin as substrate) or type B (phenylethylamine as substrate) monoamine oxidase, IC50 concentrations being above 10(-5) M. These data extend evidence that duloxetine inhibits serotonin and norepinephrine transporters in vivo, actions that may lead to therapeutic efficacy in mental depression.
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PMID:Effects of duloxetine, an antidepressant drug candidate, on concentrations of monoamines and their metabolites in rats and mice. 751 56

Previously we showed that prolonged exposure to severe hypoxia produces decreased peripheral chemoreceptor responsiveness to hypoxia and attenuates central nervous system (CNS) chemosensory translation, which together may contribute to the decreased hypoxic ventilatory response (HVR) in chronic hypoxia. In this study, we sought to determine whether the central or peripheral activity of endogenous dopamine modulates this decreased HVR. We examined the effects of peripheral and central dopamine receptor blockade on HVR and carotid sinus nerve (CNS) response to hypoxia in controls and in cats exposed to a simulated altitude of 5500 m for 3 weeks. Domperidone increased CSN response to hypoxia in hypoxic cats to levels similar to those observed in controls. HVR was also augmented by domperidone in hypoxic cats, but remained below that of controls. As a result, the CNS chemosensory translation remained reduced in hypoxic animals. We further treated animals with haloperidol. However, this combined treatment with domperidone and haloperidol led to no further increase in CSN or ventilatory responses to hypoxia, or in CNS chemosensory translation in hypoxic cats. Thus, decreased HVR in hypoxic cats is mediated both by depression of hypoxic sensitivity of the carotid body, which is largely dopaminergic, and by decreased CNS chemosensory translation which must involve non-dopaminergic mechanisms.
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PMID:Decreased carotid body hypoxic sensitivity in chronic hypoxia: role of dopamine. 852 21

Duloxetine is a dual serotonin (5-HT)/norepinephrine (NE) re-uptake blocker with antidepressant potential. In the present in vivo electrophysiological study, the changes in the function of the rat 5-HT and NE systems after 2- and 21-day administration of duloxetine (20 mg/kg/day) were assessed in the dorsal hippocampus and the dorsal raphe nucleus (DRN). The firing rate of DRN neurons was decreased after 2 days of duloxetine, but returned to the control level after 21-day administration. This recovery of firing rate was presumably due to the desensitization of the DRN somatodendritic 5-HT1A autoreceptors found after long-term duloxetine administration. Overall serotonergic tone was assessed by examining the ability of the 5-HT1A antagonist WAY 100635 to alter hippocampal firing. WAY 100635 increased hippocampal firing rates in 21-day treated rats to a greater extent than in 2-day treated or control rats, suggesting that long-term administration induced an increase in endogenous levels of 5-HT in postsynaptic regions. This increase in 5-HT levels was accompanied by selective changes in the 5-HT and NE systems induced by long-term duloxetine administration, i.e., the desensitization of the alpha-2 adrenergic heteroreceptor on 5-HT terminals and the continued blockade of the 5-HT transporters. In contrast, the sensitivity of the alpha-2 adrenergic and terminal 5-HT1B autoreceptors, as well as that of the postsynaptic 5-HT1A receptor after 21-day treatment was unchanged. Therefore, this study demonstrates that duloxetine increases serotonergic tone in a limbic forebrain structure and may therefore be effective in the treatment of depression.
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PMID:Electrophysiological characterization of the effect of long-term duloxetine administration on the rat serotonergic and noradrenergic systems. 958 May 77

Lilly is developing duloxetine, a 5-HT and norepinephrine uptake inhibitor as a potential treatment for depression and urinary incontinence. In Japan, it is being jointly developed with Shionogi [187401]. Phase III trials for depression and phase II trials for urinary incontinence are underway in Japan [296442,328887]. Lilly expects to file for depression in 2002 and phase III trials for urinary incontinence are planned to start enrollment by the end of 2000 [358429,370526,373870]. Duloxetine has a half-life of 10 to 15 h in humans, and parameters reach a steady-state after 3 days of daily administration. In a 6-week, open-label study duloxetine was safe and well tolerated in 79 clinically depressed patients. Clinical response occurred in 78% of patients, and remission occurred in 60%. Insomnia and nausea occurred with an incidence of 20% [300881]. Duloxetine may offer advantages over existing antidepressants, such as Lilly's fluoxetine, because of faster recovery and fewer side effects [190226]. In June 2000, Morgan Stanley Dean Witter predicted duloxetine would reach the market in 2002 with annual sales in this year of US $50 million, rising to $200 million in 2005 [373870]. In February 1999, Deutsche Bank predicted Lilly's sales at US $200 million in 2002 rising to $400 million in 2003 [316821]. In May 2000, Deutsche Bank had made further predictions, stating that filing for duloxetine is expected in the fourth quarter of 2001, and peak sales are expected to exceed US $500 million. Also in February 1999, Lehman Brothers predicted the first major launch date (US and ex-US) to be 2002, with the year of peak sales to be 2008 [319225]. In August 1999, this prediction changed, and the expected launch date became 2001, with an 80% probability of reaching the market and sales peaking at US $150 million in 2012 [349228].
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PMID:Duloxetine Eli Lilly & Co. 1124 87

Duloxetine is a serotonin (5-HT) and norepinephrine (NE) uptake inhibitor in pre-registration for depression. In vivo studies demonstrate that duloxetine inhibits 5-HT and NE transporters and this may induce an antidepressant effect [159168]. In humans, duloxetine has a low affinity for most 5-HT subtypes and for muscarinic, histamine H1, alpha1-adrenergic, alpha2-adrenergic and dopamine D2 receptors [444103]. Thus, it is not surprising that the meta-analysis of four recent clinical studies suggests duloxetine is a potent and well-tolerated antidepressant [429723]. By December 2001, Lilly had filed an NDA for depression. The launch of duloxetine is planned for the second half of 2002 [434250], [436220]. In April 2002, filing for stress urinary incontinence was anticipated for later in 2002 [456894]. Analysts at Banc of America predicted in April 2002, that the drug will be launched in the first quarter of 2003. The company projects US $400 million in revenue in 2003 and anticipates duloxetine to reach peak sales of over US $1 billion [450920]. Analysts at Morgan Stanley, projected US $25 million in sales in the fourth quarter 2002, rising to US $900 million in 2006 [450937]. At the same time, Credit Suisse First Boston anticipated launch for late 2002, with US $220 million in duloxetine revenues in 2003 and US $457 million in 2004 [450936].
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PMID:Duloxetine Eli Lilly. 1221 18

Existing therapies for major depressive disorder (MDD) have either limited efficacy and/or poor tolerability. The present study examined the effects of duloxetine, a potent and balanced dual reuptake inhibitor of serotonin (5-HT) and norepinephrine (NE), in patients with MDD. Adult patients (N = 267) with MDD were randomly assigned to receive duloxetine (60 mg/day) or placebo in this 9-week, multi-center, double-blind, parallel-group clinical trial. Efficacy was evaluated using the 17-item Hamilton Depression Rating Scale (HAMD(17)), Visual Analog Scales (VAS) for pain, Clinical Global Impression of Severity (CGI-S), Patient's Global Impression of Improvement (PGI-I), and Quality of Life in Depression Scale (QLDS). Safety was evaluated by assessing discontinuation rates, adverse event rates, vital signs, and laboratory tests. Duloxetine (60 mg QD) significantly reduced the HAMD(17) total score compared with placebo at the end of 9-week therapy. Estimated probabilities of response and remission were 65 and 43%, respectively, for duloxetine compared with 42 and 28% for placebo. Duloxetine also reduced overall pain, back pain, shoulder pain and time in pain while awake significantly more than placebo. Global measures of improvement, including PGI-I and QLDS, were significantly improved by duloxetine compared with placebo. Discontinuations due to adverse events were more frequent for duloxetine-treated patients (12.5%) than for placebo-treated patients (4.3%). Nausea, dry mouth, dizziness, and constipation were more frequent for duloxetine than placebo. There was no significant incidence of hypertension, nor any other safety issues. Duloxetine 60 mg administered once daily appears to be a safe and effective treatment for MDD.
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PMID:Duloxetine 60 mg once daily dosing versus placebo in the acute treatment of major depression. 1239 7

Dysregulation within central monoaminergic systems is believed to underlie the pathology of depression. Drugs that selectively inhibit the reuptake of central monoamines have been used clinically to alleviate symptoms of depressive illnesses. Duloxetine, a novel compound currently under investigation for the treatment of depression, binds selectively with high affinity to both norepinephrine (NE) and serotonin (5-HT) transporters and lacks affinity for monoamine receptors within the central nervous system. It has been suggested that dual inhibition of monoamine reuptake processes may offer advantages over other antidepressants currently in use. In preclinical studies, duloxetine mimics many physiologic effects of antidepressants. Consistent with other antidepressants, duloxetine, by acute administration, elevates extracellular monoamine levels, while by chronic administration it does not alter basal monoamine levels. Like the selective serotonin reuptake inhibitor, fluoxetine, by microiontophoretic application, duloxetine inhibits neuronal cell firing. However, in comparison with fluoxetine, duloxetine is a more potent serotonin reuptake inhibitor. Furthermore, in behavioral experiments, duloxetine attenuates immobility in forced swim tests in animal models of depression to a greater extent than several other commonly used antidepressants. In a six-week open label uncontrolled study, duloxetine was evaluated in patients with a history of depression. Duloxetine was effective in treating depression as determined by marked reduction in Hamilton Depression Rating scores. Adverse effects reported during duloxetine treatment were minor and similar to those of other antidepressants. In an eight-week multicenter, double-blind, placebo-controlled study in patients with a major depressive disorder, duloxetine was effective as an antidepressant, particularly in patients with greater symptom severity. Only limited data are available regarding the pharmacokinetic profile of duloxetine in humans, although a half-life of 10 to 15 h has been reported. Studies conducted in healthy human subjects confirm the preclinical profile of duloxetine as an inhibitor of 5-HT and NE reuptake. Taken together, existing data suggest that duloxetine is a novel and effective antidepressant.
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PMID:Duloxetine pharmacology: profile of a dual monoamine modulator. 1248 Nov 92


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