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British Journal of Pharmacology May 2024We extend the characterization of the TRPM8 antagonist VBJ103 with tests of selectivity, specificity and distribution, therapeutic efficacy of systemic administration...
BACKGROUND AND PURPOSE
We extend the characterization of the TRPM8 antagonist VBJ103 with tests of selectivity, specificity and distribution, therapeutic efficacy of systemic administration against oxaliplatin-induced cold hyperalgesia and the impact of systemic administration on core body temperature (CBT).
EXPERIMENTAL APPROACH
Selectivity at human TRPA1 and TRPV1 as well as in vitro safety profiling was determined. Effects of systemic administration of VBJ103 were evaluated in a model of oxaliplatin-induced cold hyperalgesia. Both peripheral and centrally mediated effects of VBJ103 on CBT were assessed with radiotelemetry.
KEY RESULTS
VBJ103 had no antagonist activity at TRPV1 and TRPA1, but low potency TRPA1 activation. The only safety liability detected was partial inhibition of the dopamine transporter (DAT). VBJ103 delivered subcutaneously dose-dependently attenuated cold hypersensitivity in oxaliplatin-treated mice at 3, 10 and 30 mg·kg (n = 7, P < 0.05). VBJ103 (30 mg·kg) antinociception was influenced by neither the TRPA1 antagonist HC-030031 nor the DAT antagonist GBR12909. Subcutaneous administration of VBJ103 (3, 10 and 30 mg·kg, but not 100 or 300 mg·kg, n = 7) decreased CBT (2°C). Intraperitoneal (i.p.) administration of VBJ103 (3, 10 and 30 mg·kg) dose-dependently decreased CBT to an extent larger than that detected with subcutaneous administration. Intracerebroventricular (i.c.v.) administration (306 nmol/1 μL; n = 5) did not alter CBT.
CONCLUSIONS AND IMPLICATIONS
We achieve therapeutic efficacy with subcutaneous administration of a novel TRPM8 antagonist that attenuates deleterious influences on CBT, a side effect that has largely prevented the translation of TRPM8 as a target.
PubMed: 38794851
DOI: 10.1111/bph.16429 -
Pharmaceuticals (Basel, Switzerland) May 2024The relapse rate of substance abusers is high, and addiction rehabilitation adjunct drugs need to be developed urgently. There have been numerous reports on blocking the... (Review)
Review
The relapse rate of substance abusers is high, and addiction rehabilitation adjunct drugs need to be developed urgently. There have been numerous reports on blocking the formation of substance addiction, but studies on drugs that can alleviate withdrawal symptoms are very limited. Both the dopamine transporter (DAT) hypothesis and D3 dopamine receptor (D3R) hypothesis are proposed. DAT activators reduce the extracellular dopamine level, and D3R antagonists reduce the neuron's sensitivity to dopamine, both of which may exacerbate the withdrawal symptoms subsequently. The D3R partial agonist SK608 has biased signaling properties via the G-protein-dependent pathway but did not induce D3R desensitization and, thus, may be a promising drug for the withdrawal symptoms. Drugs for serotoninergic neurons or GABAergic neurons and anti-inflammatory drugs may have auxiliary effects to addiction treatments. Drugs that promote structural synaptic plasticity are also discussed.
PubMed: 38794185
DOI: 10.3390/ph17050615 -
International Journal of Molecular... May 2024Parkinson's disease (PD) is a progressive disorder characterized by the apoptosis of dopaminergic neurons in the basal ganglia. This study explored the potential effects...
Parkinson's disease (PD) is a progressive disorder characterized by the apoptosis of dopaminergic neurons in the basal ganglia. This study explored the potential effects of aminophylline, a non-selective adenosine A and A receptor antagonist, on catalepsy and gait in a haloperidol-induced PD model. Sixty adult male Swiss mice were surgically implanted with guide cannulas that targeted the basal ganglia. After seven days, the mice received intraperitoneal injections of either haloperidol (experimental group, PD-induced model) or saline solution (control group, non-PD-induced model), followed by intracerebral infusions of aminophylline. The assessments included catalepsy testing on the bar and gait analysis using the Open Field Maze. A two-way repeated-measures analysis of variance (ANOVA), followed by Tukey's post hoc tests, was employed to evaluate the impact of groups (experimental × control), aminophylline (60 nM × 120 nM × saline/placebo), and interactions. Significance was set at 5%. The results revealed that the systemic administration of haloperidol in the experimental group increased catalepsy and dysfunction of gait that paralleled the observations in PD. Co-treatment with aminophylline at 60 nM and 120 nM reversed catalepsy in the experimental group but did not restore the normal gait pattern of the animals. In the non-PD induced group, which did not present any signs of catalepsy or motor dysfunctions, the intracerebral dose of aminophylline did not exert any interference on reaction time for catalepsy but increased walking distance in the Open Field Maze. Considering the results, this study highlights important adenosine interactions in the basal ganglia of animals with and without signs comparable to those of PD. These findings offer valuable insights into the neurobiology of PD and emphasize the importance of exploring novel therapeutic strategies to improve patient's catalepsy and gait.
Topics: Animals; Catalepsy; Mice; Male; Aminophylline; Disease Models, Animal; Gait; Haloperidol; Parkinson Disease
PubMed: 38791229
DOI: 10.3390/ijms25105191 -
International Journal of Molecular... May 2024Astrocytes actively participate in neurotransmitter homeostasis by bidirectional communication with neuronal cells, a concept named the tripartite synapse, yet their...
Astrocytes actively participate in neurotransmitter homeostasis by bidirectional communication with neuronal cells, a concept named the tripartite synapse, yet their role in dopamine (DA) homeostasis remains understudied. In the present study, we investigated the kinetic and molecular mechanisms of DA transport in cultured striatal astrocytes of adult rats. Kinetic uptake experiments were performed using radiolabeled [H]-DA, whereas mRNA expression of the dopamine, norepinephrine, organic cation and plasma membrane monoamine transporters (DAT, NET, OCTs and PMAT) and DA receptors D1 and D2 was determined by qPCR. Additionally, astrocyte cultures were subjected to a 24 h treatment with the DA receptor agonist apomorphine, the DA receptor antagonist haloperidol and the DA precursor L-DOPA. [H]-DA uptake exhibited temperature, concentration and sodium dependence, with potent inhibition by desipramine, nortriptyline and decynium-22, suggesting the involvement of multiple transporters. qPCR revealed prominent mRNA expression of the NET, the PMAT and OCT1, alongside lower levels of mRNA for OCT2, OCT3 and the DAT. Notably, apomorphine significantly altered NET, PMAT and D1 mRNA expression, while haloperidol and L-DOPA had a modest impact. Our findings demonstrate that striatal astrocytes aid in DA clearance by multiple transporters, which are influenced by dopaminergic drugs. Our study enhances the understanding of regional DA uptake, paving the way for targeted therapeutic interventions in dopaminergic disorders.
Topics: Animals; Astrocytes; Dopamine; Rats; Corpus Striatum; Haloperidol; Kinetics; Dopamine Plasma Membrane Transport Proteins; Apomorphine; Cells, Cultured; Male; Receptors, Dopamine D1; Biological Transport; Levodopa
PubMed: 38791173
DOI: 10.3390/ijms25105135 -
GeroScience May 2024Dietary restriction (DR) and hypoxia (low oxygen) extend lifespan in Caenorhabditis elegans through the induction of a convergent downstream longevity gene, fmo-2....
Dietary restriction (DR) and hypoxia (low oxygen) extend lifespan in Caenorhabditis elegans through the induction of a convergent downstream longevity gene, fmo-2. Flavin-containing monooxygenases (FMOs) are highly conserved xenobiotic-metabolizing enzymes with a clear role in promoting longevity in nematodes and a plausible similar role in mammals. This makes them an attractive potential target of small molecule drugs to stimulate the health-promoting effects of longevity pathways. Here, we utilize an fmo-2 fluorescent transcriptional reporter in C. elegans to screen a set of 80 compounds previously shown to improve stress resistance in mouse fibroblasts. Our data show that 19 compounds significantly induce fmo-2, and 10 of the compounds induce fmo-2 more than twofold. Interestingly, 9 of the 10 high fmo-2 inducers also extend lifespan in C. elegans. Two of these drugs, mitochondrial respiration chain complex inhibitors, interact with the hypoxia pathway to induce fmo-2, whereas two dopamine receptor type 2 (DRD2) antagonists interact with the DR pathway to induce fmo-2, indicating that dopamine signaling is involved in DR-mediated fmo-2 induction. Together, our data identify nine drugs that each (1) increase stress resistance in mouse fibroblasts, (2) induce fmo-2 in C. elegans, and (3) extend nematode lifespan, some through known longevity pathways. These results define fmo-2 induction as a viable approach to identifying and understanding mechanisms of putative longevity compounds.
PubMed: 38787463
DOI: 10.1007/s11357-024-01207-y -
Addiction Biology May 2024Addictive properties of propofol have been demonstrated in both humans and animals. The nucleus accumbens (NAc) shell (NAsh) in the brain, along with the interactions...
Addictive properties of propofol have been demonstrated in both humans and animals. The nucleus accumbens (NAc) shell (NAsh) in the brain, along with the interactions between N-methyl-D-aspartate receptor (NMDAR) and the dopamine D1 receptor (D1R), as well as their downstream ERK/CREB signalling pathway in the NAc, are integral in regulating reward-seeking behaviour. Nevertheless, it remains unclear whether NMDARs and the NMDAR-D1R/ERK/CREB signalling pathway in the NAsh are involved in mediating propofol addiction. To investigate it, we conducted experiments with adult male Sprague-Dawley rats to establish a model of propofol self-administration behaviour. Subsequently, we microinjected D-AP5 (a competitive antagonist of NMDARs, 1.0-4.0 μg/0.3 μL/site) or vehicle into bilateral NAsh in rats that had previously self-administered propofol to examine the impact of NMDARs within the NAsh on propofol self-administration behaviour. Additionally, we examined the protein expressions of NR2A and NR2B subunits, and the D1R/ERK/CREB signalling pathways within the NAc. The results revealed that propofol administration behaviour was enhanced by D-AP5 pretreatment in NAsh, accompanied by elevated expressions of phosphorylation of NR2A (Tyr1246) and NR2B (Tyr1472) subunits. There were statistically significant increases in the expressions of D1Rs, as well as in the phosphorylated ERK1/2 (p-ERK1/2) and CREB (p-CREB). This evidence substantiates a pivotal role of NMDARs in the NAsh, with a particular emphasis on the NR2A and NR2B subunits, in mediating propofol self-administration behaviour. Furthermore, it suggests that this central reward processing mechanism may operate through the NMDAR-D1R/ERK/CREB signal transduction pathway.
Topics: Animals; Nucleus Accumbens; Propofol; Receptors, N-Methyl-D-Aspartate; Male; Rats, Sprague-Dawley; Receptors, Dopamine D1; Self Administration; Rats; Signal Transduction; Cyclic AMP Response Element-Binding Protein; MAP Kinase Signaling System
PubMed: 38782631
DOI: 10.1111/adb.13401 -
BMJ Case Reports May 2024We report the case of a man in his mid-80s with diabetes mellitus who presented to the emergency department with a 1-day history of right-sided choreiform movements and...
We report the case of a man in his mid-80s with diabetes mellitus who presented to the emergency department with a 1-day history of right-sided choreiform movements and falls. Laboratory tests revealed blood glucose of 597 mg/dL. Non-contrast CT imaging of his head demonstrated a faint hyperdensity involving the left lentiform nucleus and brain MRI showed a hyperintensity in the left basal ganglia on T1-weighted images. These lesions are typical of diabetic striatopathy. Symptoms of hemichorea/hemiballismus did not resolve with glycaemic control and several pharmacological agents were tried with eventual improvement with risperidone. He was discharged to a rehabilitation facility and had mild persistent arm chorea at 6-month follow-up.
Topics: Humans; Male; Chorea; Dyskinesias; Aged, 80 and over; Risperidone; Magnetic Resonance Imaging; Antipsychotic Agents; Diabetes Complications; Diabetes Mellitus, Type 2; Tomography, X-Ray Computed
PubMed: 38782432
DOI: 10.1136/bcr-2023-259046 -
PloS One 2024Corydalis yanhusuo W.T. Wang is a traditional herb. Benzylisoquinoline alkaloids (BIAs) are the main pharmacological active ingredients that play an important role in...
Corydalis yanhusuo W.T. Wang is a traditional herb. Benzylisoquinoline alkaloids (BIAs) are the main pharmacological active ingredients that play an important role in sedation, relieving pain, promoting blood circulation, and inhibiting cancer cells. However, there are few studies on the biosynthetic pathway of benzylisoquinoline alkaloids in Corydalis yanhusuo, especially on some specific components, such as tetrahydropalmatine. We carried out widely targeted metabolome and transcriptomic analyses to construct the biosynthetic pathway of benzylisoquinoline alkaloids and identified candidate genes. In this study, 702 metabolites were detected, including 216 alkaloids. Protoberberine-type and aporphine-type alkaloids are the main chemical components in C. yanhusuo bulbs. Key genes for benzylisoquinoline alkaloids biosynthesis, including 6-OMT, CNMT, NMCH, BBE, SOMT1, CFS, SPS, STOX, MSH, TNMT and P6H, were successfully identified. There was no significant difference in the content of benzylisoquinoline alkaloids and the expression level of genes between the two suborgans (mother-bulb and son-bulb). The expression levels of BIA genes in the expansion stage (MB-A and SB-A) were significantly higher than those in the maturity stage (MB-C and SB-C), and the content of benzylisoquinoline alkaloids was consistent with the pattern of gene regulation. Five complete single genes were likely to encode the functional enzyme of CoOMT, which participated in tetrahydropalmatine biosynthesis in C. yanhusuo bulbs. These studies provide a strong theoretical basis for the subsequent development of metabolic engineering of benzylisoquinoline alkaloids (especially tetrahydropalmatine) of C. yanhusuo.
Topics: Corydalis; Metabolomics; Plant Roots; Alkaloids; Transcriptome; Benzylisoquinolines; Gene Expression Regulation, Plant; Biosynthetic Pathways; Gene Expression Profiling; Berberine Alkaloids; Metabolome
PubMed: 38781178
DOI: 10.1371/journal.pone.0304258 -
Epidemiology and Psychiatric Sciences May 2024Accumulating studies have assessed mortality risk associated with mood-stabilizers, the mainstay treatment for bipolar disorder (BD). However, existing data were mostly...
AIMS
Accumulating studies have assessed mortality risk associated with mood-stabilizers, the mainstay treatment for bipolar disorder (BD). However, existing data were mostly restricted to suicide risk, focused on lithium and valproate and rarely adequately adjusted for potential confounders. This study aimed to assess comparative mortality risk with all, natural and unnatural causes between lithium, valproate and three frequently prescribed second-generation antipsychotics (SGA), with adjustment for important confounders.
METHODS
This population-based cohort study identified 8137 patients with first-diagnosed BD, who had exposed to lithium ( = 1028), valproate ( = 3580), olanzapine ( = 797), quetiapine ( = 1975) or risperidone ( = 757) between 2002 and 2018. Data were retrieved from territory-wide medical-record database of public healthcare services in Hong Kong. Propensity-score (PS)-weighting method was applied to optimize control for potential confounders including pre-existing chronic physical diseases, substance/alcohol use disorders and other psychotropic medications. PS-weighted Cox proportional-hazards regression was conducted to assess risk of all-, natural- and unnatural-cause mortality related to each mood-stabilizer, compared to lithium. Three sets of sensitivity analyses were conducted by restricting to patients with (i) length of cumulative exposure to specified mood-stabilizer ≥90 days and its medication possession ratio (MPR) ≥90%, (ii) MPR of specified mood-stabilizer ≥80% and MPR of other studied mood-stabilizers <20% and (iii) monotherapy.
RESULTS
Incidence rates of all-cause mortality per 1000 person-years were 5.9 (95% confidence interval [CI]: 4.5-7.6), 8.4 (7.4-9.5), 11.1 (8.3-14.9), 7.4 (6.0-9.2) and 12.0 (9.3-15.6) for lithium-, valproate-, olanzapine-, quetiapine- and risperidone-treated groups, respectively. BD patients treated with olanzapine (PS-weighted hazard ratio = 2.07 [95% CI: 1.33-3.22]) and risperidone (1.66 [1.08-2.55]) had significantly higher all-cause mortality rate than lithium-treated group. Olanzapine was associated with increased risk of natural-cause mortality (3.04 [1.54-6.00]) and risperidone was related to elevated risk of unnatural-cause mortality (3.33 [1.62-6.86]), relative to lithium. The association between olanzapine and increased natural-cause mortality rate was consistently affirmed in sensitivity analyses. Relationship between risperidone and elevated unnatural-cause mortality became non-significant in sensitivity analyses restricted to low MPR in other mood-stabilizers and monotherapy. Valproate- and lithium-treated groups did not show significant differences in all-, natural- or unnatural-cause mortality risk.
CONCLUSION
Our data showed that olanzapine and risperidone were associated with higher mortality risk than lithium, and further supported the clinical guidelines recommending lithium as the first-line mood-stabilizer for BD. Future research is required to further clarify comparative mortality risk associated with individual SGA agents to facilitate risk-benefit evaluation of alternative mood-stabilizers to minimize avoidable premature mortality in BD.
Topics: Humans; Bipolar Disorder; Antipsychotic Agents; Female; Male; Adult; Middle Aged; Valproic Acid; Propensity Score; Antimanic Agents; Cohort Studies; Quetiapine Fumarate; Olanzapine; Hong Kong; Risperidone; Lithium; Cause of Death
PubMed: 38779809
DOI: 10.1017/S2045796024000337 -
Behavioural Brain Research Jul 2024Both dopamine (DA) and serotonin (5-HT) play key roles in numerous functions including motor control, stress response and learning. So far, there is scarce or...
Both dopamine (DA) and serotonin (5-HT) play key roles in numerous functions including motor control, stress response and learning. So far, there is scarce or conflicting evidence about the effects of 5-HT1A and 5-HT2A receptor (R) agonists and antagonists on recognition memory in the rat. This also holds for their effect on cerebral DA as well as 5-HT release. In the present study, we assessed the effects of the 5-HTR agonist 8-OH-DPAT and antagonist WAY100,635 and the 5-HTR agonist DOI and antagonist altanserin (ALT) on rat behaviors. Moreover, we investigated their impact on monoamine efflux by measuring monoamine transporter binding in various regions of the rat brain. After injection of either 8-OH-DPAT (3 mg/kg), WAY100,635 (0.4 mg/kg), DOI (0.1 mg/kg), ALT (1 mg/kg) or the respective vehicle (saline, DMSO), rats underwent an object and place recognition memory test in the open field. Upon the assessment of object exploration, motor/exploratory parameters and feces excretion, rats were administered the monoamine transporter radioligand N-o-fluoropropyl-2b-carbomethoxy-3b-(4-[I]iodophenyl)-nortropane ([I]-FP-CIT; 8.9 ± 2.6 MBq) into the tail vein. Regional radioactivity accumulations in the rat brain were determined post mortem. Compared vehicle, administration of 8-OH-DPAT impaired memory for place, decreased rearing behavior, and increased ambulation as well as head-shoulder movements. DOI administration led to a reduction in rearing behavior but an increase in head-shoulder motility relative to vehicle. Feces excretion was diminished after ALT relative to vehicle. Dopamine transporter (DAT) binding was increased in the caudateputamen (CP), but decreased in the nucleus accumbens (NAC) after 8-OH-DPAT relative to vehicle. Moreover, DAT binding was decreased in the NAC after ALT relative to vehicle. Findings indicate that 5-HTR inhibition and 5-HTR activation may impair memory for place. Furthermore, results imply associations not only between recognition memory, motor/exploratory behavior and emotionality but also between the respective parameters and the levels of available DA in CP and NAC.
Topics: Animals; Dopamine Plasma Membrane Transport Proteins; Male; Recognition, Psychology; Exploratory Behavior; Rats; Receptor, Serotonin, 5-HT1A; Receptor, Serotonin, 5-HT2A; Motor Activity; Brain; Emotions; Serotonin 5-HT1 Receptor Agonists; Serotonin 5-HT2 Receptor Agonists; Rats, Wistar
PubMed: 38777263
DOI: 10.1016/j.bbr.2024.115051