Immediate angiographic control after intra-arterial nimodipine administration underestimates the vasodilatory effect.

Intra-arterial nimodipine administration is a widely used rescue therapy for cerebral vasospasm. Although it is known that its effect sets in with delay, there is little evidence in current literature. Our aim was to prove that the maximal vasodilatory effect is underestimated in direct angiographic controls. We reviewed all cases of intra-arterial nimodipine treatment for subarachnoid hemorrhage-related cerebral vasospasm between January 2021 and December 2022. Inclusion criteria were availability of digital subtraction angiography runs before and after nimodipine administration and a delayed run for the most affected vessel at the end of the procedure to decide on further escalation of therapy. We evaluated nimodipine dose, timing of administration and vessel diameters. Delayed runs were performed in 32 cases (19 patients) with a mean delay of 37.6 (± 16.6) min after nimodipine administration and a mean total nimodipine dose of 4.7 (± 1.2) mg. Vessel dilation was more pronounced in delayed vs. immediate controls, with greater changes in spastic vessel segments (n = 31: 113.5 (± 78.5%) vs. 32.2% (± 27.9%), p < 0.0001) vs. non-spastic vessel segments (n = 32: 23.1% (± 13.5%) vs. 13.3% (± 10.7%), p < 0.0001). In conclusion intra-arterially administered nimodipine seems to exert a delayed vasodilatory effect, which should be considered before escalation of therapy.

Dexamethasone Addition Impairs the Therapeutic Effects of Nimodipine for Subarachnoid Hemorrhage: An Experimental Animal Study.

AIM: To evaluate the effects of the combination of nimodipine and dexamethasone in subarachnoid hemorrhage (SAH). MATERIAL AND METHODS: In this study, 35 female adult Wistar Albino rats were randomly assigned to four groups: Sham (n=8), SAH with no treatment (n=9), SAH with nimodipine (n=9, oral gavage, 12 mg/kg, BID) treatment, and SAH with combined therapy with nimodipine and dexamethasone (n=9, intraperitoneally, 1mg/kg, BID). The "cisterna magna double injection of autologous blood" model was used. The animals were euthanized 5 days after the first injection. RESULTS: Of the total, five rats died before euthanasia. The SAH+Nontreatment group showed the worst score in neurological examinations, and the most severe histopathological findings were noted in terms of vasospasm. The SAH+Nimodipine group showed the best neurological score and the closest histopathological results to those of the Sham group, whereas adding dexamethasone to nimodipine treatment (the SAH+Nimodipine+Dexamethasone group) worsened the neurological and histopathological outcomes. CONCLUSION: We thus concluded that the therapeutic effects of nimodipine were impaired when combined with dexamethasone. We thus hypothesized that dexamethasone possibly induces the CYP3A4-enzyme that metabolizes nimodipine. However, it should be noted that our results are based on laboratory findings obtained on a small sample, therefore further studies with drug-drug interaction on a larger sample size through CYP3A4-enzyme and clinical confirmation are warranted.

Gene Polymorphisms and Drug-Drug Interactions Determine the Metabolic Profile of Blonanserin.

This study aimed to evaluate the effects of cytochrome P450 3A4 (CYP3A4) gene polymorphism and drug interaction on the metabolism of blonanserin. Human recombinant CYP3A4 was prepared using the Bac-to-Bac baculovirus expression system. A microsomal enzyme reaction system was established, and drug-drug interactions were evaluated using Sprague-Dawley rats. Ultra-performance liquid chromatography-tandem mass spectrometry was used to detect the concentrations of blonanserin and its metabolite. Compared with wild type CYP34A, the relative clearance of blonanserin by CYP3A4.29 significantly increased to 251.3%, while it decreased notably with CYP3A4.4, 5, 7, 8, 9, 10, 12, 13, 14, 16, 17, 18, 23, 24, 28, 31, 33, and 34, ranging from 6.09% to 63.34%. Among 153 tested drugs, nimodipine, felodipine, and amlodipine were found to potently inhibit the metabolism of blonanserin. Moreover, the inhibitory potency of nimodipine, felodipine, and amlodipine varied with different CYP3A4 variants. The half-maximal inhibitory concentration and enzymatic kinetics assay demonstrated that the metabolism of blonanserin was noncompetitively inhibited by nimodipine in rat liver microsomes and was inhibited in a mixed manner by felodipine and amlodipine in both rat liver microsomes and human liver microsomes. When nimodipine and felodipine were coadministered with blonanserin, the area under the blood concentration-time curve (AUC)(0-t), AUC(0-∞), and C max of blonanserin increased. When amlodipine and blonanserin were combined, the C max of blonanserin C increased remarkably. The vast majority of CYP3A4 variants have a low ability to catalyze blonanserin. With combined administration of nimodipine, felodipine, and amlodipine, the elimination of blonanserin was inhibited. This study provides the basis for individualized clinical use of blonanserin. SIGNIFICANCE STATEMENT: The enzyme kinetics of novel CYP3A4 enzymes for metabolizing blonanserin were investigated. Clearance of blonanserin by CYP3A4.4, 5, 7-10, 12-14, 16-18, 23-24, 28, 31, 33, and 34 decreased notably, but increased with CYP3A4.29. Additionally, we established a drug interaction spectrum for blonanserin, in which nimodipine, felodipine, and amlodipine kinetics exhibited mixed inhibition. Moreover, their inhibitory potencies decreased with CYP3A4.4 and 5 compared to CYP3A4.1. This study provides essential data for personalized clinical use of blonanserin.

Pharmacological Prevention of Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (aSAH) include early brain injury and delayed neurologic deterioration, which may result from delayed cerebral ischemia (DCI). Complex pathophysiological mechanisms underlie DCI, which often includes angiographic vasospasm (aVSP) of cerebral arteries. METHODS: Despite the study of many pharmacological therapies for the prevention of DCI in aSAH, nimodipine-a dihydropyridine calcium channel blocker-remains the only drug recommended universally in this patient population. A common theme in the research of preventative therapies is the use of promising drugs that have been shown to reduce the occurrence of aVSP but ultimately did not improve functional outcomes in large, randomized studies. An example of this is the endothelin antagonist clazosentan, although this agent was recently approved in Japan. RESULTS: The use of the only approved drug, nimodipine, is limited in practice by hypotension. The administration of nimodipine and its counterpart nicardipine by alternative routes, such as intrathecally or formulated as prolonged release implants, continues to be a rational area of study. Additional agents approved in other parts of the world include fasudil and tirilazad. CONCLUSIONS: We provide a brief overview of agents currently being studied for prevention of aVSP and DCI after aSAH. Future studies may need to identify subpopulations of patients who can benefit from these drugs and perhaps redefine acceptable outcomes to demonstrate impact.

[Acacetin protects rats from cerebral ischemia-reperfusion injury by regulating TLR4/NLRP3 signaling pathway].

This study aims to investigate the mechanism of acacetin in protecting rats from cerebral ischemia-reperfusion injury via the Toll-like receptor 4(TLR4)/NOD-like receptor protein 3(NLRP3) signaling pathway. Wistar rats were randomized into sham, model, low-and high-dose acacetin, and nimodipine groups, with 10 rats in each group. The rat model of middle cerebral artery occlusion(MCAO) was established with the improved suture method in other groups except the sham group. The neurological deficit score and cerebral infarction volume of each group were evaluated 24 h after modeling. Enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of interleukin-1ß(IL-1ß), IL-6, tumor necrosis factor-α(TNF-α), malondialdehyde(MDA), supe-roxide dismutase(SOD), and glutathione(GSH). Western blot was employed to determine the expression levels of B-cell lymphonoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and TLR4/NLRP3 signaling pathway-related proteins(TLR4, p-NF-κB/NF-κB, NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1ß, and cleaved IL-1ß) in the rat brain tissue. Hematoxylin-eosin(HE) staining was employed to reveal the histopathological changes in the ischemic area. Compared with the sham group, the modeling of MCAO increased the neurological deficit score and cerebral infarction volume, elevated the IL-1ß, IL-6, TNF-α, and MDA levels and lowered the SOD and GSH levels in the brain tissue(P<0.05). Compared with the MCAO model group, low-and high-dose acacetin and nimodipine decreased the neurological deficit score and cerebral infarction volume, lowered the IL-1ß, IL-6, TNF-α, and MDA levels and elevated the SOD and GSH levels in the brain tissue(P<0.05). Compared with the sham group, the model group showed up-regulated protein levels of Bax, TLR4, p-NF-κB/NF-κB, NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1ß, and cleaved IL-1ß and down-regulated protein level of Bcl-2 in the brain tissue(P<0.05). Compared with the MCAO model group, the acacetin and nimodipine groups showed down-regulated protein levels of Bax, TLR4, p-NF-κB/NF-κB, NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1ß, and cleaved IL-1ß and up-regulated protein level of Bcl-2 in the brain tissue(P<0.05). In conclusion, acacetin regulates the TLR4/NLRP3 signaling pathway to inhibit neuroinflammatory response and oxidative stress, thus exerting the protective effect on cerebral ischemia-reperfusion injury in rats.

Nimodipine Reduces Microvasospasms After Experimental Subarachnoid Hemorrhage.

BACKGROUND: The only established pharmacological treatment option improving outcomes for patients suffering from subarachnoid hemorrhage (SAH) is the L-type-calcium channel inhibitor nimodipine. However, the exact mechanisms of action of nimodipine conferring neuroprotection after SAH have yet to be determined. More recently, spasms of the cerebral microcirculation were suggested to play an important role in reduced cerebral perfusion after SAH and, ultimately, outcome. It is unclear whether nimodipine may influence microvasospasms and, thus, microcirculatory dysfunction. The aim of the current study was, therefore, to assess the effect of nimodipine on microvasospasms after experimental SAH. METHODS: Male C57Bl/6 N mice (n=3-5/group) were subjected to SAH using the middle cerebral artery perforation model. Six hours after SAH induction, a cranial window was prepared, and the diameter of cortical microvessels was assessed in vivo by 2-photon-microscopy before, during, and after nimodipine application. RESULTS: Nimodipine significantly reduced the number of posthemorrhagic microvasospasms. The diameters of nonspastic vessels were not affected. CONCLUSIONS: Our results show that nimodipine reduces the formation of microvasospasms, thus, shedding new light on the mode of action of a drug routinely used for the treatment of SAH for >3 decades. Furthermore, L-type Ca2+ channels may be involved in the pathophysiology of microvasospasm formation.

Vasodilatory effects of tadalafil in an animal model of cerebral vasospasm: Comparative analysis with oral nimodipine.

OBJECTIVES: Cerebral vasospasm is one of the most fatal complications after spontaneous aneurysmal subarachnoid hemorrhage. Although various treatments have been tried for the treatment of cerebral vasospasm so far, the effect is insignificant or temporary except for oral nimodipine. Phosphodiesterase isozyme type 5 inhibitor, which is used to treat erection dysfunction, recently has been known to have a cerebrovascular vasodilation. It is thought that this will be effective in cerebral vasospasm, and the effect will be compared and analyzed with oral nimodipine through an animal model of cerebral vasospasm. MATERIAL AND METHODS: A total of 40 rabbits were used to make subarachnoid hemorrhage model and were divided into three groups - a control group, nimodipine group, and tadalafil group. The cerebral vessels were angiographically measured before and on the third day of subarachnoid hemorrhage. Then vertebrobasilar arteries were harvested and evaluated. Under the microscope, lumen area and media area were measured for each group and were compared. RESULTS: Angiographically, tadalafil group showed significant vasodilation compared with the control group (p < 0.01). Histologically, tadalafil showed a similar effect on lumen and on media area to that of nimodipine group compared with the control group. CONCLUSIONS: Cerebral vasospasm could leave neurologic deficit or sequelae even after proper treatment. Therefore, prevention is important. Tadalafil showed preventive effect against cerebral vasospasm and vasodilative effect similar to that of nimodipine. Therefore, tadalafil could be considered an alternative preventive treatment of cerebral vasospasm.

Dantrolene Significantly Improves Cerebral Blood Flow in a Rat Model of Hemorrhagic Vasospasms.

INTRODUCTION: A cerebral vasospasm (CVSP) is a potent vasoconstriction of the cerebral vasculature and the primary cause of morbidity and mortality following a subarachnoid hemorrhage. The middle cerebral artery (MCA) is commonly affected by CVSPs. Concomitant administration of dantrolene and nimodipine synergistically reduces vasospasms in aortic rings from Sprague Dawley rats. To determine if the effects observed in the systemic vasculature extend to the cerebral circulation, we investigated the effect of intravenous administration of dantrolene (2.5 mg/kg) and nimodipine (1 mg/kg and 2 mg/kg) on MCA blood flow velocity (BFV) 7 days after the induction of CVSPs. METHODS: Vasospasms were induced by bathing the left common carotid artery with autologous whole blood. Age-matched sham rats were used as controls. BFV, mean arterial pressure (MAP), and heart rate (HR) were measured with a PeriFlux 5000 Laser Doppler System, and a CODA non-invasive blood pressure system, before and after administering the drugs. Morphometric evaluations were also performed to assess vascular alterations. RESULTS: BFV was reduced by 37% with dantrolene alone (n = 6, p ≤ 0.05) and by 27% with 2 mg/kg nimodipine (n = 6, p < 0.05), while it was not affected by 1 mg/kg nimodipine. The combination of 1 mg/kg nimodipine with dantrolene, however, decreased BFV by 35% (from 435.70 ± 21.53 to 284.30 ± 23.13 perfusion units, n = 7, p ≤ 0.05). A similar reduction (31%) was obtained with dantrolene and 2 mg/kg nimodipine (from 536.00 ± 32.61 to 367.80 ± 40.93 perfusion units, n = 6, p ≤ 0.05). Neither MAP nor HR was affected by dantrolene or nimodipine alone. The combination of dantrolene with 2 mg/kg nimodipine, however, decreased MAP and increased HR. Furthermore, 7 days after the induction of vasospasms, lumen area of the left common carotid artery decreased, whereas media thickness and the wall-to-lumen ratio increased when compared to contralateral controls. The latter finding suggests that vascular remodeling was present at this stage. CONCLUSION: Altogether, our results indicate that 2.5 mg/kg dantrolene significantly reduces BFV in the MCA without altering systemic hemodynamic parameters to a similar extent than the highest dose of nimodipine or the combination of dantrolene and the lowest dose of nimodipine. Therefore, dantrolene may provide a promising alternative to lower the risk, or partially revert, CVSP.

Impact of the Voltage-Gated Calcium Channel Antagonist Nimodipine on the Development of Oligodendrocyte Precursor Cells.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). While most of the current treatment strategies focus on immune cell regulation, except for the drug siponimod, there is no therapeutic intervention that primarily aims at neuroprotection and remyelination. Recently, nimodipine showed a beneficial and remyelinating effect in experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Nimodipine also positively affected astrocytes, neurons, and mature oligodendrocytes. Here we investigated the effects of nimodipine, an L-type voltage-gated calcium channel antagonist, on the expression profile of myelin genes and proteins in the oligodendrocyte precursor cell (OPC) line Oli-Neu and in primary OPCs. Our data indicate that nimodipine does not have any effect on myelin-related gene and protein expression. Furthermore, nimodipine treatment did not result in any morphological changes in these cells. However, RNA sequencing and bioinformatic analyses identified potential micro (mi)RNA that could support myelination after nimodipine treatment compared to a dimethyl sulfoxide (DMSO) control. Additionally, we treated zebrafish with nimodipine and observed a significant increase in the number of mature oligodendrocytes (* p≤ 0.05). Taken together, nimodipine seems to have different positive effects on OPCs and mature oligodendrocytes.

ISSLS PRIZE in basic science 2023: Lactate in lumbar discs-metabolic waste or energy biofuel? Insights from in vivo MRS and T2r analysis following exercise and nimodipine in healthy volunteers.

PURPOSE: To quantitatively assess the dynamic changes of Lactate in lumbar discs under different physiological conditions using MRS and T2r. METHODS: In step1, MRS and T2r sequences were standardized in 10 volunteers. Step2, analysed effects of high cellular demand. 66 discs of 20 volunteers with no back pain were evaluated pre-exercise (EX-0), immediately after targeted short-time low back exercises (EX-1) and 60 min after (EX-2). In Step 3, to study effects of high glucose and oxygen concentration, 50 lumbar discs in 10 volunteers were analysed before (D0) and after 10 days intake of the calcium channel blocker, nimodipine (D1). RESULTS: Lactate showed a distinctly different response to exercise in that Grade 1 discs with a significant decrease in EX-1 and a trend for normalization in Ex-2. In contrast, Pfirrmann grade 2 and 3 and discs above 40 years showed a higher lactate relative to proteoglycan in EX-0, an increase in lactate EX-1 and mild dip in Ex-2. Similarly, following nimodipine, grade 1 discs showed an increase in lactate which was absent in grade 2 and 3 discs. In contrast, exercise and Nimodipine had no significant change in T2r values and MRS spectrum of proteoglycan, N-acetyl aspartate, carbohydrate, choline, creatine, and glutathione across age groups and Pfirrmann grades. CONCLUSION: MRS documented changes in lactate response to cellular demand which suggested a 'Lactate Symbiotic metabolic Pathway'. The differences in lactate response preceded changes in Proteoglycan/hydration and thus could be a dynamic radiological biomarker of early degeneration.

The effect of the calcium channel blocker nimodipine on hippocampal BDNF/Ach levels in rats with experimental cognitive impairment.

OBJECTIVE: Alzheimer's disease (AD) occurs in approximately 10% to 30% of individuals aged 65 or older worldwide. Novel therapeutic agents therefore need to be discovered in addition to traditional medications. Nimodipine appears to possess the potential to reverse cognitive impairment-induced dysfunction in learning and memory through its regulatory effect on the brain-derived neurotrophic factor (BDNF), acetylcholine (Ach), and acetylcholinesterase (AChE) pathway in the hippocampus and prefrontal cortex. METHODS: Twenty-four male Sprague Dawley rats weighing 380 ± 10 g were used for behavioral and biochemical analyses. These were randomly and equally assigned into one of three groups. Group 1 received saline solution alone via the intraperitoneal (i.p) route, and Group 2 received 1 mg/kg/day i.p. scopolamine once a day for three weeks for induction of learning and memory impairments. In Group 3, 10 mg/kg/day nimodipine was prepared in tap water and administered orally every day for three weeks, followed after 30 min by 1 mg/kg/day scopolamine i.p. Behavior was evaluated using the Morris Water Maze test. BDNF, ACh, and AChE levels were determined using the ELISA test in line with the manufacturer's instructions. RESULTS: Nimodipine treatment significantly increased the time spent in the target quadrant and the number of entries into the target quadrant compared to the scopolamine group alone. Additionally, BDNF and ACh levels in the hippocampus and prefrontal cortex decreased following 20-day scopolamine administration, while AChE activation increased. CONCLUSION: Nimodipine exhibited potentially beneficial effects by ameliorating cognitive decline following scopolamine administration in the hippocampus and prefrontal cortex.

Effects of breviscapine on cerebral ischemia-reperfusion injury and intestinal flora imbalance by regulating the TLR4/MyD88/NF-κB signaling pathway in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The plant Erigeron breviscapus (Vant.) Hand.-Mazz.,a Chinese herbal medicine with multiple pharmacological effects and clinical applications, has been traditionally used in the treatment of paralysis caused by stroke and joint pain from rheumatism by the Yi minority people of Southwest China for generations.However, its mechanism involves many factors and has not been fully clarified. AIM OF THE STUDY: Taking intestinal flora as the target, the protective effect of extract(breviscapine) of E. breviscapus on cerebral ischemia and its possible mechanism were discussed from the perspective of brain inflammatory pathway and intestinal CYP3A4, which depends on intestinal flora. MATERIALS AND METHODS: In this study, we first verified the binding ability between major active ingredient of Erigeron breviscapus and the core target TLR4 protein by molecular docking using Vina software.We established a rat model of cerebral ischemia-reperfusion injury in vivo.The neurological function of rats was scored by Bederson score table, the cerebral infarction volume was detected by TTC staining, and the serum NSE level was detected by ELASA. 16S rRNA sequencing was used to detect the intestinal flora of rats in each group.The expression levels of cerebral TLR4/MyD88/NF-κB and CYP3A4 mRNA and protein in different intestinal segments were detected by qRT-PCR and Western blot. RESULTS: Compared with the model group, the neurological injury score, infarct volume and serum NSE concentration of breviscapine low, medium and high dose groups and nimodipine groups decreased significantly. Meanwhile, breviscapine could significantly reduce the expression level of the TLR4/MyD88/NF-κB in brain tissue and CYP3A4 in different intestinal segments of rats with cerebral ischemia-reperfusion injury. In addition, breviscapine also significantly ameliorated intestinal flora dysbiosis of rats with cerebral ischemia-reperfusion injury. CONCLUSIONS: Breviscapine can protect rats from cerebral ischemia-reperfusion injury by regulating intestinal flora, inhibiting brain TLR4/MyD88/NF-κB inflammatory pathway and intestinal CYP3A4 expression.

Enhancement of nerve regeneration with nimodipine treatment after sciatic nerve injury.

Peripheral nerve injuries (PNI/s) are common orthopedic conditions, characterized by motor and sensory deficits in the damaged region. There is growing evidence that the L-type calcium channel antagonist nimodipine has neuroprotective and neuroregenerative effects in animal models of neurological disorders. The efficacy of nimodipine on improving motor function and sensation following a sciatic nerve crush model was investigated in male Wistar rats as a model of PNI. At different time periods following damage, we evaluated motor function, sensory recovery, electrophysiology, histomorphometry, and gene expression. Moreover, we used histological and mass ratio analysis of the gastrocnemius muscle to assess atrophy. Our findings suggest that the nimodipine improves motor and sensory function more quickly in the damaged region 2, 4, and 6 weeks after 1 week of treatment. Nimodipine treatment also increased the number of myelinated fibers while decreasing their thickness, as shown by histomorphometry. Additionally, nimodipine treatment increases the mRNA levels of neurotrophic factors (BDNF and NGF), which are known to contribute to the regeneration of injured neurons. The impact of nimodipine in PNI recovery may be due to its stimulation of the CREB signaling pathway and suppression of pro-inflammatory factor production.

N-methyl-D-aspartate receptor-mediated spinal cord ischemia-reperfusion injury and its protective mechanism.

INTRODUCTION: This study investigated the specific mechanism of N-methyl-D-aspartate (NMDA) receptor-mediated spinal cord ischemia-reperfusion by comparing the protective effects of the voltage-gated Ca2+ channel blocker nimodipine and the NMDA receptor blocker K-1024 on the spinal cord. MATERIAL AND METHODS: In this study, 42 SD rats were divided randomly into four groups: non-blocking (n = 6), normal saline (n = 12), K-1024 (n = 12) and nimodipine (n = 12). The rats in three groups (saline, K-1024, nimodipine) received an intraperitoneal injection 30 minutes before ischemia. In these three groups, 6 out of 12 rats were selected randomly to have their thoracic aorta blocked with a balloon to induce spinal cord ischemia for 10 minutes. Then, the spinal cord tissues were collected. The remaining six rats were evaluated for nerve function at 1, 2, 4 and 8 hours after reperfusion. The lumbar spinal cord was removed for histological examination. The release of neurotransmitter amino acids was observed by high-pressure liquid chromatography, and the protein expression level of neuronal nitric oxide synthase (nNOS) in the spinal cord was determined by immunohistochemistry. RESULTS: All the animals in the normal saline group and five in the nimodipine group were paralysed after ischemia. Compared with the normal saline and nimodipine groups, the rats in the K-1024 group had more normal motor neurons and better behavioural scores. In addition, the histopathology of the rats in the K-1024 group was significantly better than in the normal saline and nimodipine groups. After 10 minutes of ischemia, there was no significant difference in glutamate concentration in each group. The protein expression level of nNOS in the K-1024 group was significantly downregulated compared with the saline and nimodipine groups. At 8 hours after reperfusion, the protein expression level of nNOS in the K-1024 group was significantly upregulated compared with the normal saline group. CONCLUSIONS: The specific mechanism of the NMDA receptor blocker K-1024 in protection against spinal cord ischemia-reperfusion injury is related closely to the inhibition of NMDA receptors and the downregulation of the protein expression level of nNOS.

The effect of CYP3A4 genetic polymorphism and drug interaction on the metabolism of istradefylline.

AIM: This study investigated into the effect of CYP3A4 genetic polymorphism on istradefylline metabolism. Moreover, the potential drug-drug interaction with istradefylline was determined as well as underlied mechanism. METHOD: In vitro, enzymatic reaction was performed to determine the kinetic parameters of CYP3A4 and its variants on catalyzing istradefylline. Meanwhile, the rat liver microsomes incubation assay was applied to screen interacting drugs. In vivo, SD rats were used to investigate the selected drug interaction. UPLC-MS/MS was used to detect the metabolite M1. RESULT: The results demonstrated that the relative clearance rate of CYP3A4.29 decrease significantly compared with CYP3A4.1. But there is no statistically diverse in activities among CYP3A4.1, 2 and 3. The relative clearance rates of the remaining variants are significantly decreased compared with CYP3A4.1. In addition, 148 drugs were screened to determine the potential interaction with istradefylline, among which calcium channel blockers were identified. It's indicated that nimodipine has a significant inhibitory effect on metabolizing istradefylline with IC50 of 6.927 ± 0.372 µM, which via competitive and non-competitive mixed mechanism. In vivo, when istradefylline and nimodipine was co-administered to SD rats, we found the main pharmacokinetic parameters of M1 reduced remarkably, including AUC, MRT, Cmax and CLz/F. CONCLUSION: CYP3A4 genetic polymorphism and nimodipine affect the metabolism of istradefylline. Thus, the present study provided reference data for clinical individualized medicine of istradefylline.

The Prevention and Reversal of a Phenytoin-Resistant Model by N-acetylcysteine Therapy Involves the Nrf2/P-Glycoprotein Pathway at the Blood-Brain Barrier.

The transporter hypothesis is one of the most popular hypotheses of drug-resistant epilepsy (DRE). P-glycoprotein (P-gp), a channel protein at the blood-brain barrier (BBB), plays an important role in the transport of some anti-seizure drugs from brain tissue into vessels, which reduces drug concentrations and diminishes the effects of drug treatment. We performed this study to test whether P-gp is overexpressed in DRE and identify ways to prevent and reverse DRE. In this study, we established a phenytoin (PHT)-resistant mouse model and revealed that P-gp was overexpressed at the BBB in PHT-resistant mice. The P-gp inhibitor nimodipine decreased the resistance of phenytoin. Antioxidative preventive treatment with N-acetylcysteine (NAC) prevented the mice from entering a PHT-resistant state, and NAC therapy tended to reverse PHT resistance into sensitivity. We were also able to induce PHT resistance by activating the Nrf2/P-gp pathway, which indicates that oxidative stress plays an important role in drug resistance. Taken together, these findings suggest that antioxidative therapy may be a promising strategy for overcoming DRE.

Structural Modifications of Nimodipine Lead to Novel PDE1 Inhibitors with Anti-pulmonary Fibrosis Effects.

Our previous research demonstrated that phosphodiesterase-1 (PDE1) could work as a potential target against idiopathic pulmonary fibrosis. Nimodipine, a calcium antagonist commonly used to improve hypertension, was reported to have inhibition against PDE1. Herein, a series of nimodipine analogues were discovered as novel selective and potent PDE1 inhibitors after structural modifications. Compound 2g exhibited excellent inhibitory activity against PDE1C (IC50 = 10 nM), high selectivity over other PDEs except for PDE4, and weak calcium channel antagonistic activity. Administration of compound 2g exhibited remarkable therapeutic effects in a rat model of pulmonary fibrosis induced by bleomycin and prevented myofibroblast differentiation induced by TGF-ß1. The expressions of PDE1B and PDE1C were found to be increased and concentrated in the focus of fibrosis. Compound 2g increased the levels of 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) in the lungs of rats with pulmonary fibrosis, supporting the fact that the anti-fibrosis effects of 2g were through the regulation of cAMP and cGMP.

[Protective effect and mechanism of Ershiwuwei Zhenzhu Pills on cerebral apoplexy rats].

To study the protective effect of Ershiwuwei Zhenzhu Pills on ischemic stroke rats. Ninety 4-weeks-old SPF male SD rats were randomly divided into 6 groups(n=15):sham operation group, model group, nimodipine group(12 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills high-dose group(400 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills medium-dose group(200 mg·kg~(-1)), Ershiwuwei Zhenzhu Pills low-dose group(100 mg·kg~(-1)).The permanent middle cerebral artery occlusion model(PMCAO) was established in the model group, nimodipine group, and Ershiwuwei Zhenzhu Pills groups by the improved thread plug method, while the sham operation group did not insert the thread plug.Nimodipine group and Ershiwuwei Zhenzhu Pills groups were given intragastric administration once a day for 24 days before the modeling operation, and once 1 hour before the modeling operation, while sham operation group and model group were given equal volumes of distilled water.The neuroethology of the surviving rats was measured; The volume of cerebral infarction in rats was measured by TTC method; The histopathology of rat brain was observed by HE method; The expression levels of tumor necrosis factor α(TNF-α),interleukin-1ß(IL-1ß),interleukin-6(IL-6),malondialdehyde(MDA),superoxide dismutase(SOD) and catalase(CAT) in serum were detected by ELISA;The mRNA expressions of Notch 1,Jagged 1,Hes 1 and Bcl-2 in rat brain were detected by RT-PCR;Western blot was used to detect the expression levels of caspase-3 protein in rat brain; the expression levels of vascular endothelial growth factor(VEGF) and CD34 positive cells in rat brain were detected by immunofluorescence.The low, medium and high dose groups of Ershiwuwei Zhenzhu Pills and nimodipine group could significantly reduce the neurobehavioral score and cerebral infarction volume of rats with permanent middle cerebral artery occlusion, reduce the morphological changes of nerve cells, decrease the expression of TNF-α,IL-1ß and IL-6 in rat serum, increase the activity of SOD and CAT,and reduce the level of MDA.Furthermore, the expression levels of Notch l, Jagged l, Hes l and Bcl-2 mRNA were significantly increased, and the expression level of caspase-3 protein was decreased.Meanwhile, the number of VEGF and CD34 positive cells increased in the treatment group.The differences were statistically significant. Ershiwuwei Zhenzhu Pills has a protective effect on ischemic stroke rats, and its mechanism may be related to anti-inflammation, anti-oxidation, promotion of nerve cell proliferation, inhibition nerve cell apoptosis and promotion of angiogenesis.

Nimodipine Treatment Protects Auditory Hair Cells from Cisplatin-Induced Cell Death Accompanied by Upregulation of LMO4.

Ototoxicity is one of the main dose-limiting side effects of cisplatin chemotherapy and impairs the quality of life of tumor patients dramatically. Since there is currently no established standard therapy targeting hearing loss in cisplatin treatment, the aim of this study was to investigate the effect of nimodipine and its role in cell survival in cisplatin-associated hearing cell damage. To determine the cytotoxic effect, the cell death rate was measured using undifferentiated and differentiated UB/OC-1 and UB/OC-2 cells, after nimodipine pre-treatment and stress induction by cisplatin. Furthermore, immunoblot analysis and intracellular calcium measurement were performed to investigate anti-apoptotic signaling, which was associated with a reduced cytotoxic effect after nimodipine pre-treatment. Cisplatin's cytotoxic effect was significantly attenuated by nimodipine up to 61%. In addition, nimodipine pre-treatment counteracted the reduction in LIM Domain Only 4 (LMO4) by cisplatin, which was associated with increased activation of Ak strain transforming/protein kinase B (Akt), cAMP response element-binding protein (CREB), and signal transducers and activators of transcription 3 (Stat3). Thus, nimodipine presents a potentially well-tolerated substance against the ototoxicity of cisplatin, which could result in a significant improvement in patients' quality of life.

TGF-ß1 Protects Trauma-injured Murine Cortical Neurons by Upregulating L-type Calcium Channel Cav1.2 via the p38 Pathway.

Traumatic brain injury (TBI) is a leading cause of disability and death in adolescents, and there is a lack of effective methods of treatment. The neuroprotective effects exerted by TGF-ß1 can ameliorate a range of neuronal lesions in multiple central nervous system diseases. In this study, we used an in-vitro TBI model of mechanical injury on murine primary cortical neurons and the neuro-2a cell line to investigate the neuroprotective role played by TGF-ß1 in cortical neurons in TBI. Our results showed that TGF-ß1 significantly increased neuronal viability and inhibited apoptosis for 24 h after trauma. The expression of Cav1.2, an L-type calcium channel (LTCC) isoform, decreased significantly after trauma injury, and this change was reversed by TGF-ß1. Nimodipine, a classic LTCC blocker, abolished the protective effect of TGF-ß1 on trauma-induced neuronal apoptosis. The knockdown of Cav1.2 in differentiated neuro-2a cells significantly inhibited the anti-apoptosis effect of TGF-ß1 exerted on injured neuro-2a cells. Moreover, TGF-ß1 rescued and enhanced the trauma-suppressed neuro-2a intracellular Ca2+ concentration, while the effect of TGF-ß1 was partially inhibited by nimodipine. TGF-ß1 significantly upregulated the expression of Cav1.2 by activating the p38 MAPK pathway and by inhibiting trauma-induced neuronal apoptosis. In conclusion, TGF-ß1 increased trauma-injured murine cortical neuronal activity and inhibited apoptosis by upregulating Cav1.2 channels via activating the p38 MAPK pathway. Therefore, the TGF-ß1/p38 MAPK/Cav 1.2 pathway has the potential to be used as a novel therapeutic target for TBI.