Intracerebroventricular Administration Research Articles

Changes in Astroglial Water Flow in the Pre-amyloid Phase of the STZ Model of AD Dementia.

Alzheimer's disease (AD) is an age-dependent neurodegenerative disease that is typically sporadic and has a high social and economic cost. We utilized the intracerebroventricular administration of streptozotocin (STZ), an established preclinical model for sporadic AD, to investigate hippocampal astroglial changes during the first 4 weeks post-STZ, a period during which amyloid deposition has yet to occur. Astroglial proteins aquaporin 4 (AQP-4) and connexin-43 (Cx-43) were evaluated, as well as claudins, which are tight junction (TJ) proteins in brain barriers, to try to identify changes in the glymphatic system and brain barrier during the pre-amyloid phase. Glial commitment, glucose hypometabolism and cognitive impairment were characterized during this phase. Astroglial involvement was confirmed by an increase in glial fibrillary acidic protein (GFAP); concurrent proteolysis was also observed, possibly mediated by calpain. Levels of AQP-4 and Cx-43 were elevated in the fourth week post-STZ, possibly accelerating the clearance of extracellular proteins, since these proteins actively participate in the glymphatic system. Moreover, although we did not see a functional disruption of the blood-brain barrier (BBB) at this time, claudin 5 (present in the TJ of the BBB) and claudin 2 (present in the TJ of the blood-cerebrospinal fluid barrier) were reduced. Taken together, data support a role for astrocytes in STZ brain damage, and suggest that astroglial dysfunction accompanies or precedes neuronal damage in AD.

Central angiotensin-(1–7) attenuates hypoglycemia in sepsis-like conditions via reducing systemic and hepatic inflammation

Sepsis is understood as the result of initiating systemic inflammation derived from an inadequate host response against pathogens. In its acute phase, sepsis is marked by an exacerbated reaction to infection, tissue damage, organ failure, and metabolic dysfunction. Among these, hypoglycemia, characterized by disorders of the gluconeogenesis pathway, is related to one of the leading causes of mortality in septic patients. Recent research has investigated the involvement of sympathetic efferent neuroimmune pathways during systemic inflammation. These pathways can be stimulated by several centrally administered drugs, including Angiotensin-(1–7) (Ang-(1–7)). Therefore, the present study aims to evaluate the effects of central treatment with Ang-(1–7) on hypoglycemia during endotoxemia. For this, male Wistar Hannover rats underwent stereotaxic surgery for intracerebroventricular (i.c.v.) administration of Ang-(1–7) and cannulation of the jugular vein for lipopolysaccharide (LPS) injection. Our results demonstrate that LPS was capable of inducing hypoglycemia and that prior central treatment with Ang-(1–7) attenuated this effect. Our data also show that Ang-(1–7) reduced plasma concentrations of TNF-α, IL-1β, IL-6, and nitric oxide, in addition to the decrease and increase of hepatic IL-6 and IL-10 respectively, in animals subjected to systemic inflammation by LPS, resulting in the reduction of systemic and hepatic inflammation, thus attenuating the deleterious effects of LPS on phosphoenolpyruvate carboxykinase protein content. In summary, the data suggest that central treatment with Ang-(1–7) attenuates hypoglycemia induced by endotoxemia, probably through anti-inflammatory action, leading to reestablishing hepatic gluconeogenesis.

Enhanced neuronal survival and BDNF elevation via long-term co-activation of galanin 2 (GALR2) and neuropeptide Y1 receptors (NPY1R): potential therapeutic targets for major depressive disorder

ABSTRACT Background Major Depressive Disorder (MDD) is a prevalent and debilitating condition, necessitating novel therapeutic strategies due to the limited efficacy and adverse effects of current treatments. We explored how galanin receptor 2 (GALR2) and Neuropeptide Y1 Receptor (NPYY1R) agonists, working together, can boost brain cell growth and increase antidepressant-like effects in rats. This suggests new ways to treat Major Depressive Disorder (MDD). Research Design and Methods In a controlled laboratory setting, adult naive Sprague-Dawley rats were administered directly into the brain’s ventricles, a method known as intracerebroventricular (ICV) administration, with GALR2 agonist (M1145), NPYY1R agonist, both, or in combination with a GALR2 antagonist (M871). Main outcome measures included long-term neuronal survival, differentiation, and behavioral. Results Co-administration of M1145 and NPYY1R agonist significantly enhanced neuronal survival and maturation in the ventral dentate gyrus, with a notable increase in Brain-Derived Neurotrophic Factor (BDNF) expression. This neurogenic effect was associated with an antidepressant-like effect, an outcome partially reversed by M871. Conclusions GALR2 and NPYY1R agonists jointly promote hippocampal neurogenesis and exert antidepressant-like effects in rats without adverse outcomes, highlighting their therapeutic potential for MDD. The study’s reliance on an animal model and intracerebroventricular delivery warrants further clinical exploration to confirm these promising results.

Analgesic effect of a cholinergic agonist (carbachol) in a sural nerve ligation-induced hypersensitivity mouse model

ABSTRACT Objectives Neuropathic pain is characterized by long-lasting, intractable pain. Sciatic nerve ligation is often used as an animal model of neuropathic pain, and the spared nerve injury (SNI) model, in which the common peroneal nerve (CPN) and tibial nerve (TN) are ligated, is widely used. In the present study, we evaluated the analgesic effect of a cholinergic agonist, carbachol, on a neuropathic pain model prepared by sural nerve (SN) ligation in mice. Methods The SN was tightly ligated as a branch of the sciatic nerve. Mechanical and thermal allodynia, and hyperalgesia were assessed using von Frey filaments and heat from a hot plate. The analgesic effects of intracerebroventricularly-administered morphine and carbachol were compared. Results SN ligation resulted in a significant decrease in pain threshold for mechanical stimulation 1 day after ligation. In response to thermal stimulation, allodynia was observed at 50°C and hyperalgesia at 53 and 56°C 3 days after ligation. Content of thiobarbituric acid reactive substances (TBARS) in the spinal cord increased significantly at 6 and 12 h after ligation. Acetylcholine content of the spinal cord also increased at 5 and 7 days after ligation. Intracerebroventricular administration of carbachol at 7 days after ligation produced a marked analgesic effect against mechanical and thermal stimuli, which was stronger and longer-lasting than morphine at all experimental time points. Conclusion These findings suggest that cholinergic nerves are involved in allodynia and hyperalgesia of the SN ligation neuropathic pain model.

DPP-4 inhibitors sitagliptin and PF-00734,200 mitigate dopaminergic neurodegeneration, neuroinflammation and behavioral impairment in the rat 6-OHDA model of Parkinson's disease.

Epidemiological studies report an elevated risk of Parkinson's disease (PD) in patients with type 2 diabetes mellitus (T2DM) that is mitigated in those prescribed dipeptidyl peptidase 4 (DPP-4) inhibitors. With an objective to characterize clinically translatable doses of DPP-4 inhibitors (gliptins) in a well-characterized PD rodent model, sitagliptin, PF-00734,200 or vehicle were orally administered to rats initiated either 7-days before or 7-days after unilateral medial forebrain bundle 6-hydroxydopamine (6-OHDA) lesioning. Measures of dopaminergic cell viability, dopamine content, neuroinflammation and neurogenesis were evaluated thereafter in ipsi- and contralateral brain. Plasma and brain incretin and DPP-4 activity levels were quantified. Furthermore, brain incretin receptor levels were age-dependently evaluated in rodents, in 6-OHDA challenged animals and human subjects with/without PD. Cellular studies evaluated neurotrophic/neuroprotective actions of combined incretin administration. Pre-treatment with oral sitagliptin or PF-00734,200 reduced methamphetamine (meth)-induced rotation post-lesioning and dopaminergic degeneration in lesioned substantia nigra pars compacta (SNc) and striatum. Direct intracerebroventricular gliptin administration lacked neuroprotective actions, indicating that systemic incretin-mediated mechanisms underpin gliptin-induced favorable brain effects. Post-treatment with a threefold higher oral gliptin dose, likewise, mitigated meth-induced rotation, dopaminergic neurodegeneration and neuroinflammation, and augmented neurogenesis. These gliptin-induced actions associated with 70-80% plasma and 20-30% brain DPP-4 inhibition, and elevated plasma and brain incretin levels. Brain incretin receptor protein levels were age-dependently maintained in rodents, preserved in rats challenged with 6-OHDA, and in humans with PD. Combined GLP-1 and GIP receptor activation in neuronal cultures resulted in neurotrophic/neuroprotective actions superior to single agonists alone. In conclusion, these studies support further evaluation of the repurposing of clinically approved gliptins as a treatment strategy for PD.

TAAR1 as a new target for the treatment of bipolar disorder: Anti-manic and anti-depressant activity of the novel agonist PCC0105004

Background: Bipolar disorder (BD) is a deleterious psychiatric disorder, and the available pharmacotherapies have limited efficacy with significant side effects. Trace amine-associated receptor 1 (TAAR1) is an emerging drug target for neuropsychiatric disorders such as schizophrenia and substance user disorders. However, it is unknown whether TAAR1 is involved in the pathogenesis of BD. This study examined the effects and underlying mechanisms of a novel TAAR1 agonist, PCC0105004, in a rat model of ouabain (OUA)-induced BD.Methods: Intracerebroventricular (ICV) administration of OUA-induced BD model was established. The in vitro cell-based cAMP assay was used to examine TAAR1 agonism of PCC0105004. The receptor specificity of PCC0105004 was determined by an off-target panel assay that included radioligand binding and enzymatic assays. The effects of PCC0105004 on manic-like and depressive-like behaviors were evaluated in the rat BD model. TAAR1-mediated signaling and oxidative stress parameters were biochemically determined in the prefrontal cortex and the hippocampus of rats.Results: Western blotting revealed reduced TAAR1 expression level in the prefrontal cortex but unchanged in the hippocampus in model rats. PCC0105004, a TAAR1 agonist with the agonism EC50 value of 0.06182 μM, attenuated the manic-like behaviors on the 7th day and the depressive-like behaviors on the 14th day at doses that did not affect locomotor activity in the BD rats. Mechanistically, PCC0105004 exerted its behavioral effects via the reduction of ROS damage through the phosphorylation activation of the TAAR1/Akt/GSK3β/BDNF signaling pathway.Conclusion: These results demonstrated the potential antimanic-like and antidepressant-like efficacy of a novel TAAR1 agonist PCC0105004 in rats and revealed its underlying molecular basis, which supports the possibility of TAAR1 agonists as candidate pharmacotherapeutics for BD.

CGRP causes anxiety via HP1γ–KLF11–MAOB pathway and dopamine in the dorsal hippocampus

Calcitonin gene-related peptide (CGRP) is a neuropeptide that causes anxiety behavior; however, the underlying mechanisms remain unclear. We found that CGRP modulates anxiety behavior by epigenetically regulating the HP1γ-KLF-11-MAOB pathway and depleting dopamine in the dorsal hippocampus. Intracerebroventricular administration of CGRP (0.5 nmol) elicited anxiety-like behaviors in open field, hole-board, and plus-maze tests. Additionally, we observed an increase in monoamine oxidase B (MAOB) levels and a concurrent decrease in dopamine levels in the dorsal hippocampus of mice following CGRP administration. Moreover, CGRP increased abundance the transcriptional regulator of MAOB, Krüppel-like factor 11 (KLF11), and increased levels of phosphorylated heterochromatin protein (p-HP1γ), which is involved in gene silencing, by methylating histone H3 in the dorsal hippocampus. Chromatin immunoprecipitation assay showed that HP1γ was recruited to the Klf11 enhancer by CGRP. Furthermore, infusion of CGRP (1 nmol) into the dorsal hippocampus significantly increased MAOB expression as well as anxiety-like behaviors, which were suppressed by the pharmacological inhibition or knockdown of MAOB. Together, these findings suggest that CGRP reduces dopamine levels and induces anxiety-like behavior through epigenetic regulation in the dorsal hippocampus.

A novel role of NK3 receptor signaling in bipolar disorder

Objective: Bipolar disorder (BD) affects more than 1% of the global population with limited therapeutic options. The neurokinin B (NKB)-neurokinin B receptor (NK3R) is involved in a variety of emotional activities. This study explored the role of NK3 receptor signaling in bipolar disorder.Materials and methods: In this study, a model of intracerebroventricular (ICV) administration of OUA-induced BD was used to investigate the possible role of NK3R signaling in BD. The involvement of NK3R in the expression of OUA-induced BD was assessed by genetically knocking down the NK3R-encoding TACR3 gene with shRNA approach in the hippocampus and systemic administration of a NK3R antagonist ESN364,. Biochemical techniques were used to examine the NK3R-associated signaling changes and the oxidative stress parameters in the hippocampus of BD rats.Result: The NK3R expression level was elevated in the hippocampus BD rats. Both TACR3 knockdown in the hippocampus and ESN364 treatment reversed the manic-like and depression-like behaviors in BD rats Inhibition of the NK3R signaling reversed oxidative stress-induced damage via upregulating the BDNF signaling pathway in the hippocampus.Conclusion: These results demonstrated that NK3R signaling plays a key role in the pathogenesis of BD and that pharmacological antagonist of NK3R such as ESN364 could represent a novel therapeutic strategy for the management of BD.

Response of nitrergic system in the brain of rat conditioned to intracranial self-stimulation.

The role of nitrergic system in modulating the action of psychostimulants on reward processing is well established. However, the relevant anatomical underpinnings and scope of the involved interactions with mesolimbic dopaminergic system have not been clarified. Using immunohistochemistry, we track the changes in neuronal nitric oxide synthase (nNOS) containing cell groups in the animals conditioned to intracranial self-stimulation (ICSS) via an electrode implanted in the lateral hypothalamus-medial forebrain bundle (LH-MFB) area. An increase in the nNOS immunoreactivity was noticed in the cells and fibers in the ventral tegmental area (VTA) and nucleus accumbens shell (AcbSh), the primary loci of the reward system. In addition, nNOS was up-regulated in the nucleus accumbens core (AcbC), vertical limb of diagonal band (VDB), locus coeruleus (LC), lateral hypothalamus (LH), superficial gray layer (SuG) of the superior colliculus, and periaqueductal gray (PAG). The brain tissue fragments drawn from these areas showed a change in nNOS mRNA expression, but in opposite direction. Intracerebroventricular (icv) administration of nNOS inhibitor, 7-nitroindazole (7-NI) showed decreased lever press activity in a dose-dependent manner in ICSS task. While an increase in the dopamine (DA) and 3, 4-dihydroxyphenylacetic acid (DOPAC) efflux was noted in the microdialysates collected from the AcbSh of ICSS rats, pre-administration of 7-NI (icv route) attenuated the response. The study identifies nitrergic centers that probably mediate sensory, cognitive, and motor components of the goal-directed behavior.

Investigation of Antibody Pharmacokinetics in the Brain Following Intra-CNS Administration and Development of PBPK Model to Characterize the Data.

Despite the promising potential of direct central nervous system (CNS) antibody administration to enhance brain exposure, there remains a significant gap in understanding the disposition of antibodies following different intra-CNS injection routes. To bridge this knowledge gap, this study quantitatively investigated the brain pharmacokinetics (PK) of antibodies following intra-CNS administration. The microdialysis samples from the striatum (ST), cerebrospinal fluid (CSF) samples through cisterna magna (CM) puncture, plasma, and brain homogenate samples were collected to characterize the pharmacokinetics (PK) profiles of a non-targeting antibody, trastuzumab, following intracerebroventricular (ICV), intracisternal (ICM), and intrastriatal (IST) administration. For a comprehensive analysis, these intra-CNS injection datasets were juxtaposed against our previously acquired intravenous (IV) injection data obtained under analogous experimental conditions. Our findings highlighted that direct CSF injections, either through ICV or ICM, resulted in ~ 5-6-fold higher interstitial fluid (ISF) drug exposure than IV administration. Additionally, the low bioavailability observed following IST administration indicates the existence of a local degradation process for antibody elimination in the brain ISF along with the ISF bulk flow. The study further refined a physiologically based pharmacokinetic (PBPK) model based on new observations by adding the perivascular compartments, oscillated CSF flow, and the nonspecific uptake and degradation of antibodies by brain parenchymal cells. The updated model can well characterize the antibody PK following systemic and intra-CNS administration. Thus, our research offers quantitative insight into antibody brain disposition pathways and paves the way for determining optimal dosing and administration strategies for antibodies targeting CNS disorders.

Improved seizure liability detection by combining rat hippocampal brain slice electrophysiology with in vivo behavior observation following intracerebroventricular drug administration

An adverse effect of drug candidates, seizure is a serious issue in drug development. Improving evaluation systems for seizure liability is crucial for selecting good candidates. Firstly, in vitro electrophysiological measurement by a multielectrode array system in rat hippocampal brain slices was employed to confirm an increase in electrically evoked population spike (PS) area, the occurrence of multiple population spikes (MPSs), and thereby the seizure liability of five positive control chemicals: picrotoxin, 4-aminopyridine, pentylenetetrazole, penicillin G, and chlorpromazine. Aspirin, a negative control, did not affect PS area or generate MPSs. Furthermore, baclofen, an anticonvulsant drug, decreased PS area and inhibited the increase in PS area or occurrence of MPSs induced by picrotoxin. A comparative study of seizure liability among carbapenem antibiotics revealed that tienam > carbenin > omegacin and finibax. Despite leading to a strong decrease in PS area, physostigmine, cisplatin, and paroxetine still produced MPSs. Therefore, the increase in PS area or the occurrence of the MPS are considered significant evaluation parameters for seizure liability.In contrast, the in vitro electrophysiological measurement could not detect the seizure liability of diphenhydramine or fluvoxamine. A follow-up study of in vivo mouse behavioral change induced by intracerebroventricular administration of these drugs clearly detected convulsions. The in vitro electrophysiological study using hippocampal brain slices combined with in vivo behavior observation study of drug candidates administered by intracerebroventricular injection can implement to assess the seizure liability of even small amounts, especially in the early stages of drug development.

Effects of intracerebroventricular administration of calcitonin gene-related peptide (CGRP) on sex hormones and sperm quality in rats: Erratum.

Effects of intracerebroventricular administration of calcitonin gene-related peptide (CGRP) on sex hormones and sperm quality in rats: Erratum.

Intracerebroventricular administration of TRH Agonist, RX-77368 alleviates visceral pain induced by colorectal distension in rats

Thyrotropin-releasing hormone (TRH) acts centrally to exert pleiotropic actions independently from its endocrine function, including antinociceptive effects against somatic pain in rodents. Whether exogenous or endogenous activation of TRH signaling in the brain modulates visceral pain is unknown. Adult male Sprague-Dawley rats received an intracerebroventricular (ICV) injection of the stable TRH analog, RX-77368 (10, 30 and 100 ng/rat) or saline (5 µl) or were semi-restrained and exposed to cold (4°C) for 45 min. The visceromotor response (VMR) to graded phasic colorectal distensions (CRD) was monitored using non-invasive intracolonic pressure manometry. Naloxone (1 mg/kg) was injected subcutaneously 10 min before ICV RX-77368 or saline. Fecal pellet output was monitored for 1 h after ICV injection. RX-77368 ICV (10, 30 and 100 ng/rat) reduced significantly the VMR by 56.7%, 67.1% and 81.1% at 40 mmHg and by 30.3%, 58.9% and 87.4% at 60 mmHg respectively vs ICV saline. Naloxone reduced RX-77368 (30 and 100 ng, ICV) analgesic response by 51% and 28% at 40 mmHg and by 30% and 33% at 60 mmHg respectively, but had no effect per se. The visceral analgesia was mimicked by the acute exposure to cold. At the doses of 30 and 100 ng, ICV RX-77368 induced defecation within 30 min. These data established the antinociceptive action of RX-77368 injected ICV in a model of visceral pain induced by colonic distension through recruitment of both opioid and non-opioid dependent mechanisms.

Insights into Gastrointestinal Redox Dysregulation in a Rat Model of Alzheimer's Disease and the Assessment of the Protective Potential of D-Galactose.

Recent evidence suggests that the gut plays a vital role in the development and progression of Alzheimer's disease (AD) by triggering systemic inflammation and oxidative stress. The well-established rat model of AD, induced by intracerebroventricular administration of streptozotocin (STZ-icv), provides valuable insights into the GI implications of neurodegeneration. Notably, this model leads to pathophysiological changes in the gut, including redox dyshomeostasis, resulting from central neuropathology. Our study aimed to investigate the mechanisms underlying gut redox dyshomeostasis and assess the effects of D-galactose, which is known to benefit gut redox homeostasis and alleviate cognitive deficits in this model. Duodenal rings isolated from STZ-icv animals and control groups were subjected to a prooxidative environment using 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) or H2O2 with or without D-galactose in oxygenated Krebs buffer ex vivo. Redox homeostasis was analyzed through protein microarrays and functional biochemical assays alongside cell survival assessment. Structural equation modeling and univariate and multivariate models were employed to evaluate the differential response of STZ-icv and control samples to the controlled prooxidative challenge. STZ-icv samples showed suppressed expression of catalase and glutathione peroxidase 4 (GPX4) and increased baseline activity of enzymes involved in H2O2 and superoxide homeostasis. The altered redox homeostasis status was associated with an inability to respond to oxidative challenges and D-galactose. Conversely, the presence of D-galactose increased the antioxidant capacity, enhanced catalase and peroxidase activity, and upregulated superoxide dismutases in the control samples. STZ-icv-induced gut dysfunction is characterized by a diminished ability of the redox regulatory system to maintain long-term protection through the transcription of antioxidant response genes as well as compromised activation of enzymes responsible for immediate antioxidant defense. D-galactose can exert beneficial effects on gut redox homeostasis under physiological conditions.

Effect of Intracerebroventricular Administration of Galanin-Like Peptide on Hepatokines in C57BL/6J Mice.

Galanin-like peptide (GALP) is a neuropeptide that was first isolated and identified from the porcine hypothalamus. Studies have described an anti-obesity effect of GALP. We previously found that intracerebroventricular administration of GALP in mice resulted in an increase in respiratory exchange rate 12 to 16h later. GALP may also affect glucose metabolism, but the detailed mechanism has not been elucidated. In this study, we investigated the effects of GALP on glucose and lipid metabolism in the liver. Nine-week-old male C57BL / 6J mice were administered a single intracerebroventricular dose of saline or GALP and dissected 16h later. There were no significant between-group differences in body weight and blood glucose levels. With regard to gene and protein expression, G6Pase associated with hepatic gluconeogenesis was significantly reduced in the GALP group. In addition, the hepatokines selenoprotein P and fetuin-A, which induce insulin resistance in the liver, were significantly decreased in the GALP group. These results suggest that intracerebroventricular administration of GALP decreases the expression of key hepatokines, thereby enhancing glucose metabolism.

The alpha-7 nicotinic acetylcholine receptor agonist PHA-543613 reduces food intake in male rats

Obesity is a prevalent disease, but effective treatment options remain limited. Agonists of the alpha-7 nicotinic acetylcholine receptor (α7nAChR) promote negative energy balance in mice, but these effects are not well-studied in rats. We tested the hypothesis that central administration of the α7nAChR agonist PHA-543613 (PHA) would decrease food intake and body weight in adult male Sprague Dawley rats. Intracerebroventricular (ICV) PHA administration in chow-fed rats produced a suppression of energy intake and weight gain over 24 h. Next, to evaluate effects of ICV PHA on palatable food intake, rats were maintained on a choice diet of rodent chow and 45 % high fat diet (HFD); under these conditions, ICV PHA produced no significant changes in energy intake from either food, or body weight gain, in the 24 h post-injection. However, when given a choice of chow or a higher-fat 60 % HFD, ICV PHA reduced intake of 60 % HFD, but not chow; body weight gain was also suppressed. Further experiments evaluating conditioned taste avoidance (CTA) and pica in response to ICV PHA suggested that the suppressive food intake and body weight effects after ICV injection of PHA were not due to nausea/malaise. Finally, an operant conditioning study showed that responding on a progressive ratio schedule of reinforcement for high-fat food pellets decreased after ICV PHA. Collectively, these studies show that PHA reduces energy intake under some but not all dietary conditions. Importantly, central PHA decreases both food intake as well as motivation for highly palatable, energy dense foods in rats without inducing nausea/malaise, suggesting that the α7nAChR could be a viable target for developing treatments for obesity.

Effect of intracerebroventricular administration of alglucosidase alfa in two mouse models of Lafora disease: Relevance for clinical practice

Lafora disease is a rare and fatal form of progressive myoclonic epilepsy with onset during early adolescence. The disease is caused by mutations in EPM2A, encoding laforin, or EPM2B, encoding malin. Both proteins have functions that affect glycogen metabolism, including glycogen dephosphorylation by laforin and ubiquitination of enzymes involved in glycogen metabolism by malin. Lack of function of laforin or malin results in the accumulation of polyglucosan that forms Lafora bodies in the central nervous system and other tissues. Enzyme replacement therapy through intravenous administration of alglucosidase alfa (Myozyme®) has shown beneficial effects removing polyglucosan aggregates in Pompe disease. We evaluated the effectiveness of intracerebroventricular administration of alglucosidase alfa in the Epm2a-/- knock-out and Epm2aR240X knock-in mouse models of Lafora disease. Seven days after a single intracerebroventricular injection of alglucosidase alfa in 12-month-old Epm2a-/- and Epm2aR240X mice, the number of Lafora bodies was not reduced. Additionally, a prolonged infusion of alglucosidase alfa for 2 or 4 weeks in 6- and 9-month-old Epm2a-/- mice did not result in a reduction in the number of LBs or the amount of glycogen in the brain. These findings hold particular significance in guiding a rational approach to the utilization of novel therapies in Lafora disease.

Electrophysiological effects of kappa-opioid analgesic, RU-1205, using machine learning methods

The study is focused to the investigation of a new kappa-opioid agonist RU-1205, which exhibits an analgesic effect without causing dysphoric or aversive actions. It is assumed that this effects may be due to its functional selectivity, or the presence of an additional mechanism of action that involves blocking p38 mitogen-activated protein kinase (MAPK).The aim of the study was an experimental identification of RU-1205 mechanisms of action associated with the inhibition of MAPK p38 and functional selectivity for kappa opioid receptors.Materials and methods. The LFP activity was recorded in the male rats weighing 260–280 g (n=62) and implanted with chronic cortical and deep electrodes, after the intracerebroventricular administration of the well-studied reference substances: the selective kappa-opioid agonist U-50488 100 μg; the MAPK p38 blocker SB203580 1 μg; and the investigational compound RU-1205 at 350 μg. The weighted phase lag index (WPLI) was calculated. Subsequently, machine learning methods were employed to reduce the dimensionality and extract connectivity features using the principal component analysis method, then a signal classification was performed (models based on Gaussian processes). Using the local patch-clamp technique in the “whole-cell” configuration, the spike activity of pyramidal neurons in the basolateral amygdala was studied. Neurons were identified by their accommodation properties. After local perfusion of the test compounds, 3 dose-response curves were obtained for: (1) U-50488 at concentrations ranging from 0.001 to 10 μM; (2) combinations of U-50488 (0.001–10 μM) and RU-1205 (10 μM); and (3) the combinations of U-50488 (0.01–10 μM) and RU-1205 (100 μM).Results. The developed models made it possible to classify the compound RU-1205 as a “non-inhibitor” of MAPK p38 with a high probability. The results obtained were confirmed in patch-clamp experiments on acute brain slices where it was demonstrated that U-50488 statistically significantly increases the spike activity of pyramidal neurons of the basolateral amygdala (p <0.05), and RU-1205 interacts with U-50488, competitively suppressing its effect on the spike activity of neurons.Conclusion. The findings suggest that compound RU-1205 displays properties consistent with a functional kappa agonist activity and does not have a significant effect on MAPK p38. The study demonstrates the possibility of integrating electrophysiological measurements and advanced data analysis methods for a deep understanding of drug action and underscores the potential for further research in this area.

Orexin-A attenuated motion sickness through modulating neural activity in hypothalamus nuclei.

We evaluated the hypothesis that central orexin application could counteract motion sickness responses through regulating neural activity in target brain areas. Thec effects of intracerebroventricular (i.c.v.) injection of orexin-A and SB-334867 (OX1 antagonist) on motion sickness-induced anorexia, nausea-like behaviour (conditioned gaping), hypoactivity and hypothermia were investigated in rats subjected to Ferris wheel-like rotation. Orexin-A responsive brain areas were identified using Fos immunolabelling and were verified via motion sickness responses after intranucleus injection of orexin-A, SB-334867 and TCS-OX2-29 (OX2 antagonist). The efficacy of intranasal application of orexin-A versus scopolamine on motion sickness symptoms in cats was also investigated. Orexin-A (i.c.v.) dose-dependently attenuated motion sickness-related behavioural responses and hypothermia. Fos expression was inhibited in the ventral part of the dorsomedial hypothalamus (DMV) and the paraventricular nucleus (PVN), but was enhanced in the ventral part of the premammillary nucleus ventral part (PMV) by orexin-A (20 μg) in rotated animals. Motion sickness responses were differentially inhibited by orexin-A injection into the DMV (anorexia and hypoactivity), the PVN (conditioned gaping) and the PMV (hypothermia). SB-334867 and TCS-OX2-29 (i.c.v. and intranucleus injection) inhibited behavioural and thermal effects of orexin-A. Orexin-A (60 μg·kg-1 ) and scopolamine inhibited rotation-induced emesis and non-retching/vomiting symptoms, while orexin-A also attenuated anorexia with mild salivation in motion sickness cats. Orexin-A might relieve motion sickness through acting on OX1 and OX2 receptors in various hypothalamus nuclei. Intranasal orexin-A could be a potential strategy against motion sickness.

Systemic delivery of mutant huntingtin lowering antisense oligonucleotides to the brain using apolipoprotein A-I nanodisks for Huntington disease

Efficient delivery of therapeutics to the central nervous system (CNS) remains a major challenge for the treatment of neurological diseases. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion mutation in the HTT gene which codes for a toxic mutant huntingtin (mHTT) protein. Pharmacological reduction of mHTT in the CNS using antisense oligonucleotides (ASO) ameliorates HD-like phenotypes in rodent models of HD, with such therapies being investigated in clinical trials for HD.In this study, we report the optimization of apolipoprotein A-I nanodisks (apoA-I NDs) as vehicles for delivery of a HTT-targeted ASO (HTT ASO) to the brain and peripheral organs for HD. We demonstrate that apoA-I wild type (WT) and the apoA-I K133C mutant incubated with a synthetic lipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine, can self-assemble into monodisperse discoidal particles with diameters <20 nm that transmigrate across an in vitro blood-brain barrier model of HD. We demonstrate that apoA-I NDs are well tolerated in vivo, and that apoA-I K133C NDs show enhanced distribution to the CNS and peripheral organs compared to apoA-I WT NDs following systemic administration. ApoA-I K133C conjugated with HTT ASO forms NDs (HTT ASO NDs) that induce significant mHTT lowering in the liver, skeletal muscle and heart as well as in the brain when delivered intravenously in the BACHD mouse model of HD. Furthermore, HTT ASO NDs increase the magnitude of mHTT lowering in the striatum and cortex compared to HTT ASO alone following intracerebroventricular administration. These findings demonstrate the potential utility of apoA-I NDs as biocompatible vehicles for enhancing delivery of mutant HTT lowering ASOs to the CNS and peripheral organs for HD.