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Translational Vision Science &... Sep 2023To evaluate the pharmacology and toxicology of SAF312, a transient receptor potential vanilloid 1 (TRPV1) antagonist.
PURPOSE
To evaluate the pharmacology and toxicology of SAF312, a transient receptor potential vanilloid 1 (TRPV1) antagonist.
METHODS
TRPV1 expression in human ocular tissues was evaluated with immunohistochemistry. Inhibition of calcium influx in Chinese hamster ovary (CHO) cells expressing human TRPV1 (hTRPV1) and selectivity of SAF312 were assessed by a fluorescent imaging plate reader assay. Ocular tissue and plasma pharmacokinetics (PK) were assessed following a single topical ocular dose of SAF312 (0.5%, 1.0%, 1.5%, 2.5%) in rabbits. Safety and tolerability of SAF312 were evaluated in rabbits and dogs. Effects of SAF312 on corneal wound healing after photorefractive keratectomy (PRK) surgery were assessed in rabbits.
RESULTS
TRPV1 expression was noted in human cornea and conjunctiva. SAF312 inhibited calcium influx in CHO-hTRPV1 cells induced by pH 5.5 (2-[N-morpholino] ethanesulfonic acid), N-arachidonoylethanolamine, capsaicin, and N-arachidonoyl dopamine, with IC50 values of 5, 10, 12, and 27 nM, respectively, and inhibition appeared noncompetitive. SAF312 demonstrated high selectivity for TRPV1 (>149-fold) over other TRP channels. PK analysis showed highest concentrations of SAF312 in cornea and conjunctiva. SAF312 was found to be safe and well tolerated in rabbits and dogs up to the highest feasible concentration of 2.5%. No delay in wound healing after PRK was observed.
CONCLUSIONS
SAF312 is a potent, selective, and noncompetitive antagonist of hTRPV1 with an acceptable preclinical safety profile for use in future clinical trials.
TRANSLATIONAL RELEVANCE
SAF312, which was safe and well tolerated without causing delay in wound healing after PRK in rabbits, may be a potential therapeutic agent for ocular surface pain.
Topics: Animals; Cricetinae; Dogs; Humans; Rabbits; Calcium; CHO Cells; Conjunctiva; Cricetulus; TRPV Cation Channels
PubMed: 37672251
DOI: 10.1167/tvst.12.9.5 -
Biology Direct Aug 2023Antipsychotic drugs are the mainstay of treatment for schizophrenia and provide adjunct therapies for other prevalent psychiatric conditions, including bipolar disorder...
Antipsychotic drugs are the mainstay of treatment for schizophrenia and provide adjunct therapies for other prevalent psychiatric conditions, including bipolar disorder and major depressive disorder. However, they also induce debilitating extrapyramidal syndromes (EPS), such as Parkinsonism, in a significant minority of patients. The majority of antipsychotic drugs function as dopamine receptor antagonists in the brain while the most recent 'third'-generation, such as aripiprazole, act as partial agonists. Despite showing good clinical efficacy, these newer agents are still associated with EPS in ~ 5 to 15% of patients. However, it is not fully understood how these movement disorders develop. Here, we combine clinically-relevant drug concentrations with mutliscale model systems to show that aripiprazole and its primary active metabolite induce mitochondrial toxicity inducing robust declines in cellular ATP and viability. Aripiprazole, brexpiprazole and cariprazine were shown to directly inhibit respiratory complex I through its ubiquinone-binding channel. Importantly, all three drugs induced mitochondrial toxicity in primary embryonic mouse neurons, with greater bioenergetic inhibition in ventral midbrain neurons than forebrain neurons. Finally, chronic feeding with aripiprazole resulted in structural damage to mitochondria in the brain and thoracic muscle of adult Drosophila melanogaster consistent with locomotor dysfunction. Taken together, we show that antipsychotic drugs acting as partial dopamine receptor agonists exhibit off-target mitochondrial liabilities targeting complex I.
Topics: Animals; Mice; Aripiprazole; Antipsychotic Agents; Depressive Disorder, Major; Drosophila melanogaster; Electron Transport
PubMed: 37528429
DOI: 10.1186/s13062-023-00375-9 -
Pharmacological Research Aug 2023Schizophrenia (SCZ) is a severe psychiatric disorder characterized by positive symptoms, negative symptoms, and cognitive deficits. Current antipsychotic treatment in...
Schizophrenia (SCZ) is a severe psychiatric disorder characterized by positive symptoms, negative symptoms, and cognitive deficits. Current antipsychotic treatment in SCZ improves positive symptoms but has major side effects and little impact on negative symptoms and cognitive impairment. The pathoetiology of SCZ remains unclear, but is known to involve small GTPase signaling. Rho kinase, an effector of small GTPase Rho, is highly expressed in the brain and plays a major role in neurite elongation and neuronal architecture. This study used a touchscreen-based visual discrimination (VD) task to investigate the effects of Rho kinase inhibitors on cognitive impairment in a methamphetamine (METH)-treated male mouse model of SCZ. Systemic injection of the Rho kinase inhibitor fasudil dose-dependently ameliorated METH-induced VD impairment. Fasudil also significantly suppressed the increase in the number of c-Fos-positive cells in the infralimbic medial prefrontal cortex (infralimbic mPFC) and dorsomedial striatum (DMS) following METH treatment. Bilateral microinjections of Y-27632, another Rho kinase inhibitor, into the infralimbic mPFC or DMS significantly ameliorated METH-induced VD impairment. Two proteins downstream of Rho kinase, myosin phosphatase-targeting subunit 1 (MYPT1; Thr696) and myosin light chain kinase 2 (MLC2; Thr18/Ser19), exhibited increased phosphorylation in the infralimbic mPFC and DMS, respectively, after METH treatment, and fasudil inhibited these increases. Oral administration of haloperidol and fasudil ameliorated METH-induced VD impairment, while clozapine had little effect. Oral administration of haloperidol and clozapine suppressed METH-induced hyperactivity, but fasudil had no effect. These results suggest that METH activates Rho kinase in the infralimbic mPFC and DMS, which leads to cognitive impairment in male mice. Rho kinase inhibitors ameliorate METH-induced cognitive impairment, perhaps via the cortico-striatal circuit.
Topics: Animals; Male; Mice; Clozapine; Cognitive Dysfunction; Haloperidol; Methamphetamine; Monomeric GTP-Binding Proteins; rho-Associated Kinases; Schizophrenia; Protein Kinase Inhibitors
PubMed: 37390993
DOI: 10.1016/j.phrs.2023.106838 -
Journal of Affective Disorders Oct 2023Antipsychotic medications are increasingly used for difficult-to-treat depression in young people. However, the evidence-base for this is unclear. Our aim was to assess... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Antipsychotic medications are increasingly used for difficult-to-treat depression in young people. However, the evidence-base for this is unclear. Our aim was to assess the evidence for the efficacy of atypical antipsychotics in treating unipolar and bipolar depression in adolescents and young adults.
METHOD
We conducted a comprehensive systematic review and meta-analysis of randomized-control-trial studies (RCTs) of antipsychotic medications for 10- to 25-year-olds with unipolar and bipolar depression. The primary outcome of interest was change in depressive symptoms from baseline to trial endpoint.
RESULTS
No studies were identified that evaluated the use of antipsychotics in the treatment of unipolar depression. However, we identified four studies, of quetiapine, lurasidone and olanzapine/fluoxetine combination, comprising a total of 866 randomized patients, that evaluated treatment of bipolar depression. All studies used the Children's Depression Rating Scale-Revised (CDRS-R). Our meta-analysis revealed the weighted mean difference (WMD) was -4.58 (95 % CI, -6.59 to -2.57) between antipsychotic and placebo-treated groups. Response and remission rates were also significantly in favor of antipsychotic treatment.
LIMITATIONS
There were few studies, several did not address risk-of-bias domains and there was a lack of non-industry sponsored studies.
CONCLUSION
There is an absence of evidence for the use of antipsychotic medications in treatment of youth unipolar depression, and no recommendations can be made. There is some evidence for the efficacy of antipsychotics, specifically lurasidone and olanzapine/fluoxetine combination, in the treatment of young people with bipolar depression. However, this evidence is limited and more studies investigating the use of these medications in young people are needed.
Topics: Child; Adolescent; Young Adult; Humans; Antipsychotic Agents; Bipolar Disorder; Fluoxetine; Olanzapine; Lurasidone Hydrochloride
PubMed: 37467794
DOI: 10.1016/j.jad.2023.07.082 -
NPJ Parkinson's Disease Oct 2023It remains unclear which adjunctive drug for Parkinson's disease (PD) in combination with levodopa is more effective, tolerable, and safe. We aimed to compare the...
It remains unclear which adjunctive drug for Parkinson's disease (PD) in combination with levodopa is more effective, tolerable, and safe. We aimed to compare the efficacy, tolerability, and safety among anti-PD drugs from several classes in patients with fluctuating PD who received levodopa through network meta-analysis (NMA). Twelve anti-PD drugs belonging to 4 different drug classes (dopamine agonists, monoamine oxidase type B inhibitors, catechol-O-methyl transferase inhibitors, and an adenosine A2A receptor antagonist) were selected. We systematically searched PubMed, Embase, and the Cochrane Library for eligible randomized controlled trials (RCTs) comparing placebo with anti-PD drug or among anti-PD drugs in patients with PD who experienced motor fluctuations or wearing-off and received levodopa. We included 54 RCTs in the analysis. The NMA was performed under a frequentist framework using a random-effects model. The efficacy outcome was change in daily off-time, and the tolerability outcome was discontinuation due to all causes. Safety outcomes included discontinuation due to adverse events (AEs) and the incidence of AEs, dyskinesia, hallucination, and orthostatic hypotension. According to the surface under the cumulative ranking curve (SUCRA) in the NMA, ropinirole transdermal patch (SUCRA, 0.861) ranked the highest in efficacy, followed by pramipexole (0.762), ropinirole extended release (ER) (0.750), and safinamide (0.691). In terms of tolerability, ropinirole (0.954) ranked the highest, followed by pramipexole (0.857), safinamide (0.717), and ropinirole ER (0.708). Each anti-PD drug had different SUCRA ranking profiles for the safety outcomes. These findings suggest that ropinirole, pramipexole, and safinamide are well-balanced anti-PD drugs that satisfy both efficacy and tolerability outcomes.
PubMed: 37853009
DOI: 10.1038/s41531-023-00589-8 -
JCI Insight Aug 2023Attention-deficit hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder that affects approximately 5.3% of children and approximately 2.5% of...
Attention-deficit hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder that affects approximately 5.3% of children and approximately 2.5% of adults. There is an intimate relationship between ADHD and sleep disturbance. Specifically, individuals carry a mutation in the core circadian gene CRY1 (c. 1657 + 3A > C), which results in the deletion of exon 11 expression in the CRY1 protein (CRY1Δ11), causing them to exhibit typical ADHD symptoms. However, the underlying mechanism is still elusive. In this study, we demonstrate that Cry1Δ11 (c. 1717 + 3A > C) mice showed ADHD-like symptoms, including hyperactivity, impulsivity, and deficits in learning and memory. A hyperactive cAMP signaling pathway was found in the nucleus accumbens (NAc) of Cry1Δ11 mice. We further demonstrated that upregulated c-Fos was mainly localized in dopamine D1 receptor-expressing medium spiny neurons (DRD1-MSNs) in the NAc. Neuronal excitability of DRD1-MSNs in the NAc of Cry1Δ11 mice was significantly higher than that of WT controls. Mechanistically, the CRY1Δ11 protein, in contrast to the WT CRY1 protein, failed to interact with the Gαs protein and inhibit DRD1 signaling. Finally, the DRD1 antagonist SCH23390 normalized most ADHD-like symptoms in Cry1Δ11 mice. Thus, our results reveal hyperactive DRD1 signaling as an underlying mechanism and therapeutic target for ADHD induced by the highly prevalent CRY1Δ11 mutation.
Topics: Animals; Mice; Attention Deficit Disorder with Hyperactivity; Receptors, Dopamine D1; Signal Transduction; Exons; Mutation
PubMed: 37606043
DOI: 10.1172/jci.insight.170434 -
EMBO Reports Oct 2023A11 dopaminergic neurons regulate somatosensory transduction by projecting from the diencephalon to the spinal cord, but the function of this descending projection in...
A11 dopaminergic neurons regulate somatosensory transduction by projecting from the diencephalon to the spinal cord, but the function of this descending projection in itch remained elusive. Here, we report that dopaminergic projection neurons from the A11 nucleus to the spinal dorsal horn (dopaminergic ) are activated by pruritogens. Inhibition of these neurons alleviates itch-induced scratching behaviors. Furthermore, chemogenetic inhibition of spinal dopamine receptor D1-expressing (DRD1 ) neurons decreases acute or chronic itch-induced scratching. Mechanistically, spinal DRD1 neurons are excitatory and mostly co-localize with gastrin-releasing peptide (GRP), an endogenous neuropeptide for itch. In addition, DRD1 neurons form synapses with GRP receptor-expressing (GRPR ) neurons and activate these neurons via AMPA receptor (AMPAR). Finally, spontaneous itch and enhanced acute itch induced by activating spinal DRD1 neurons are relieved by antagonists against AMPAR and GRPR. Thus, the descending dopaminergic pathway facilitates spinal itch transmission via activating DRD1 neurons and releasing glutamate and GRP, which directly augments GRPR signaling. Interruption of this descending pathway may be used to treat chronic itch.
Topics: Humans; Receptors, Bombesin; Gastrin-Releasing Peptide; Spinal Cord; Glutamic Acid; Dopamine; Pruritus; Dopaminergic Neurons; Receptors, AMPA
PubMed: 37522391
DOI: 10.15252/embr.202256098 -
Current Opinion in Pharmacology Oct 2023Gastroparesis is a neuromuscular disorder of the upper gastrointestinal tract. Patients typically complain about early satiety, postprandial fullness, nausea and... (Review)
Review
Gastroparesis is a neuromuscular disorder of the upper gastrointestinal tract. Patients typically complain about early satiety, postprandial fullness, nausea and vomiting. Etiology is multifactorial. Treatment strategies include nutritional support, pharmacologic agents or surgery for refractory cases. Metoclopramide is the first and only FDA approved pharmacologic agent for (diabetic) Gastroparesis. A couple of compounds are currently in clinical testing. Some beacons of hope have failed recently, however. Here we present an update on possible future treatment options.
Topics: Humans; Gastroparesis; Metoclopramide
PubMed: 37639905
DOI: 10.1016/j.coph.2023.102395 -
Phytomedicine : International Journal... Dec 2023Because of the complex pathogenesis of neuropathic pain (NP), the therapeutic efficacy of existing drugs is not satisfactory. Accumulating studies have indicated that...
BACKGROUND
Because of the complex pathogenesis of neuropathic pain (NP), the therapeutic efficacy of existing drugs is not satisfactory. Accumulating studies have indicated that neuroinflammation may play a key role in NP onset and progression. Levo-tetrahydropalmatine (l-THP) has been extensively used for relieving chronic pain for decades. However, its potential mechanisms against NP have not yet been fully elucidated.
PURPOSE
Exploring and elucidating the therapeutic effect and pharmacological mechanism of l-THP in treating NP.
METHODS
RNA-seq and bioinformatics analyses were carried out to identify effective target profiling of I-THP in chronic constrictive injury (CCI) rats. The I-THP related hub targets and signaling pathways were obtained via bioinformatics analysis, then subjected to in-depth analyses through experiments in vivo. A gain-of-function study further confirmed the role of Clec7a in l-THP-mediated pain relief. Finally, the interaction between l-THP and Clec7a was verified through molecular docking and surface plasmon resonance (SPR).
RESULTS
l-THP treatment effectively alleviated mechanical and thermal allodynia in NP model rats. Functionally, the I-THP effective targets were mainly enriched in inflammatory response-related pathways. Furthermore, Clec7a-MAPK/NF-κB-NLRP3 inflammasome axis was selected as one of the potential pathways of l-THP against NP. Mechanically, l-THP markedly reduced CCI-induced Clec7a overexpression, significantly inhibited the Clec7a-triggered phosphorylation of MAPK and NF-κB-p65, and decreased the expression of pyroptosis-related protein NLRP3 and Caspase-1-p20. The analgesic effect of l-THP on NP was partly eliminated when transfecting the overexpression vector virus pLVSOClec7a. Importantly, molecular docking and SPR data revealed that l-THP directly binds with the Clec7a protein.
CONCLUSION
This study is the first to indicate that l-THP may exert an analgesic effect through inhibiting neuroinflammation via the Clec7a-MAPK/NF-κB-NLRP3 inflammasome axis, supporting the clinical utility of l-THP in NP therapy.
Topics: Rats; Animals; NF-kappa B; Inflammasomes; NLR Family, Pyrin Domain-Containing 3 Protein; Neuroinflammatory Diseases; Molecular Docking Simulation; Analgesics; Neuralgia
PubMed: 37741158
DOI: 10.1016/j.phymed.2023.155075 -
Annals of Medicine and Surgery (2012) Feb 2024Cardiovascular disease (CVD) is the most common cause of morbidity and mortality worldwide. Bromocriptine is a partial antagonist for D1 dopamine receptors while also... (Review)
Review
Cardiovascular disease (CVD) is the most common cause of morbidity and mortality worldwide. Bromocriptine is a partial antagonist for D1 dopamine receptors while also serving as a selective agonist on D2 dopamine receptors as a dopamine receptor agonist. Apart from prolactin inhibiting action, bromocriptine has some beneficial effects on the blood pressure, plasma norepinephrine levels and vascular resistance. Dopamine D2 receptor activation of bromocriptine is associated with the antihypertensive effect, which lowers blood pressure via inhibiting sympathetic nerve activity and Na/K ATPase activity. Plasma levels of the pro-inflammatory cytokines such as interleukin (IL)-1B and IL-18, chemokine CCL2/ MCP-1/, and the pro-inflammatory hormone prolactin, all of which are elevated and linked to accelerated cardiometabolic illness, were decreased because of bromocriptine therapy. The most common side effects of Bromocriptine use are dizziness, nausea, headache, vomiting and hypotension. Bromocriptine is mainly contraindicated in patients with syncope with hypotension, psychosis, and type I diabetes mellitus. The authors suggest that developing therapies directed to increase D2 receptor expression and function by drugs like Bromocriptine can provide practical and novelistic approaches to prevent and manage myocardial and renal injury in the cardiovascular disease patients.
PubMed: 38333315
DOI: 10.1097/MS9.0000000000001642