Novel Scorpion Toxin ω-Buthitoxin-Hf1a Selectively Inhibits Calcium Influx via CaV3.3 and CaV3.2 and Alleviates Allodynia in a Mouse Model of Acute Postsurgical Pain.

Venom peptides have evolved to target a wide range of membrane proteins through diverse mechanisms of action and structures, providing promising therapeutic leads for diseases, including pain, epilepsy, and cancer, as well as unique probes of ion channel structure-function. In this work, a high-throughput FLIPR window current screening assay on T-type CaV3.2 guided the isolation of a novel peptide named ω-Buthitoxin-Hf1a from scorpion Hottentotta franzwerneri crude venom. At only 10 amino acid residues with one disulfide bond, it is not only the smallest venom peptide known to target T-type CaVs but also the smallest structured scorpion venom peptide yet discovered. Synthetic Hf1a peptides were prepared with C-terminal amidation (Hf1a-NH2) or a free C-terminus (Hf1a-OH). Electrophysiological characterization revealed Hf1a-NH2 to be a concentration-dependent partial inhibitor of CaV3.2 (IC50 = 1.18 µM) and CaV3.3 (IC50 = 0.49 µM) depolarized currents but was ineffective at CaV3.1. Hf1a-OH did not show activity against any of the three T-type subtypes. Additionally, neither form showed activity against N-type CaV2.2 or L-type calcium channels. The three-dimensional structure of Hf1a-NH2 was determined using NMR spectroscopy and used in docking studies to predict its binding site at CaV3.2 and CaV3.3. As both CaV3.2 and CaV3.3 have been implicated in peripheral pain signaling, the analgesic potential of Hf1a-NH2 was explored in vivo in a mouse model of incision-induced acute post-surgical pain. Consistent with this role, Hf1a-NH2 produced antiallodynia in both mechanical and thermal pain.

Verapamil-Loaded Cubosomes for Enhancing Intranasal Drug Delivery: Development, Characterization, Ex Vivo Permeation, and Brain Biodistribution Studies.

Verapamil hydrochloride (VRP), an antihypertensive calcium channel blocker drug has limited bioavailability and short half-life when taken orally. The present study was aimed at developing cubosomes containing VRP for enhancing its bioavailability and targeting to brain for cluster headache (CH) treatment as an off-label use. Factorial design was conducted to analyze the impact of different components on entrapment efficiency (EE%), particle size (PS), zeta potential (ZP), and percent drug release. Various in-vitro characterizations were performed followed by pharmacokinetic and brain targeting studies. The results revealed the significant impact of glyceryl monooleate (GMO) on increasing EE%, PS, and ZP of cubosomes with a negative influence on VRP release. The remarkable effect of Poloxamer 407 (P407) on decreasing EE%, PS, and ZP of cubosomes was observed besides its influence on accelerating VRP release%. The DSC thermograms indicated the successful entrapment of the amorphous state of VRP inside the cubosomes. The design suggested an optimized formulation containing GMO (50% w/w) and P407 (5.5% w/w). Such formulation showed a significant increase in drug permeation through nasal mucosa with high Er value (2.26) when compared to VRP solution. Also, the histopathological study revealed the safety of the utilized components used in the cubosomes preparation. There was a significant enhancement in the VRP bioavailability when loaded in cubosomes owing to its sustained release favored by its direct transport to brain. The I.N optimized formulation had greater BTE% and DTP% at 183.53% and 90.19%, respectively in comparison of 41.80% and 59% for the I.N VRP solution.

Anti-Hypertensive Drugs Moderate the Relationship of Blood Pressure with Alzheimer's Pathologies and Neurodegenerative Markers in Non-Demented Hypertensive Older Adults.

BACKGROUND: We aimed to explore whether the relationships of blood pressures (BPs) with Alzheimer's disease (AD) endophenotypes varied by usage of antihypertensive drugs (AHDs). METHODS: A total of 765 non-demented older adults (mean age: 74.4 years; female: 43.1%) with a self-reported history of hypertension were followed for 6 years. Multiple linear regression and linear-mixed effect models were used to investigate the interaction effects of five categories of AHDs (angiotensin-converting enzyme inhibitors [ACEI], angiotensin II receptor blockers [ARBs], ß-blocker, calcium channel blockers [CCB], diuretic) with BPs (systolic blood pressure [SBP], diastolic blood pressure [DBP], and pulse pressure [PP]) on AD core pathology and neurodegenerative markers. RESULTS: After Bonferroni correction, significant interaction effects of BPs with AHDs were observed. Elevated SBP or PP in late-life was associated with higher levels of cerebral Aß burden (diuretic alone/ß-blocker × SBP), higher levels of CSF tau proteins (diuretic × SBP/PP, ARBs/CCB × SBP), and lower volume of entorhinal region (ß-blocker × SBP, diuretic × PP) only among hypertensive patients who received no anti-hypertensive treatments, while these associations became compromised or null for users of specific AHDs except for ACEI. Compared to taking other classes of AHDs, elevated SBP in late-life was associated with lower cerebral Aß burden in diuretic users (padjusted = 0.08) and was associated with higher CSF tau proteins in ACEI alone users (padjusted = 0.03). Longitudinal data validated the above-mentioned interaction effects on changes of cerebral Aß burden (padjusted < 0.05), CSF tau proteins (padjusted < 0.10), and brain atrophy (padjusted < 0.05). CONCLUSIONS: The relationships of late-life BP with AD pathology and neurodegeneration could be modified by anti-hypertensive treatments and varied by AHD classification. These findings provide preliminary evidence for tailored BP management strategy for preventing AD among late-life hypertensive adults.

A Retrospective Study to Evaluate Real-world Evidence of Azelnidipine in Indian Patients (REDEFINE Study).

INTRODUCTION: Azelnidipine, a selective calcium channel blocker, effectively lowers blood pressure (BP) and heart rate (HR) in hypertensive patients, as demonstrated in a retrospective real-world evidence (RWE) study in Indian patients. MATERIALS AND METHODS: This was a retrospective cohort study that included 882 patients aged 18 years or older who had been on azelnidipine treatment for the last 3 months for mild to moderate hypertension (HTN). A structured proforma was utilized to gather data from prescribing physicians to assess the efficacy of azelnidipine (8 and 16 mg) as monotherapy or in combination with other antihypertensive drugs. The primary endpoints of the study were to capture changes in systolic blood pressure (SBP) and diastolic BP (DBP) from baseline to the subsequent visits (4 and 12 weeks), while the secondary endpoints were to measure similar changes in the diabetic group and to estimate the proportion of patients achieving target BP of <130/80 mm Hg and <140/90 mm Hg, respectively. RESULTS: The overall mean reduction of systolic/diastolic BP from baseline to 12 weeks was 13.92/7.91 mm Hg (p-value < 0.0001). The mean reduction of systolic/diastolic BP from baseline to 12 weeks was 11.77/7.43 mm Hg (p-value < 0.0001) in newly diagnosed HTN patients, while in known cases of HTN, it was 16.50/8.48 mm Hg (p-value < 0.0001). In the diabetic group, the mean reduction was 15.35/8.69 mm Hg (p-value < 0.0001). Overall the study showed that in 44 (4.99%) and 408 (46.26%) patients, target BP of <130/80 mm Hg and <140/90 mm Hg, respectively was achieved. The mean change in HR from baseline was a reduction of 5.22 beats/minute. CONCLUSION: Azelnidipine can be an effective antihypertensive drug to treat mild to moderate HTN in Indian patients.

The Promise of Cilnidipine in Hypertension with Comorbidities: National Consensus Statement: National Consensus Group Comprises Cardiologists, Nephrologists, and Diabetologists from India in a National Meet at New Delhi held on 22nd May 2022.

The rapidly increasing burden of hypertension is responsible for premature deaths from cardiovascular disease (CVD), renal disease, and stroke, with a tremendous public health and financial burden. Hypertension detection, treatment, and control vary worldwide; it is still low, particularly in low- and middle-income countries (LMICs). High blood pressure (BP) and CVD risk have a strong, linear, and independent association. They contribute to alarming numbers of all-cause and CVD deaths. A major culprit for increased hypertension is sympathetic activity, and further complications of hypertension are heart failure, ischemic heart disease (IHD), stroke, and renal failure. Now, antihypertensive interventions have emerged as a global public health priority to reduce BP-related morbidity and mortality. Calcium channel blockers (CCB) are highly effective vasodilators. and the most common drugs used for managing hypertension and CVD. Cilnidipine, with both L- and N-type calcium channel blocking activity, is a promising 4th generation CCB. It causes vasodilation via L-type calcium channel blockade and inhibits the sympathetic nervous system (SNS) via N-type calcium channel blockade. Cilnidipine, which acts as a dual L/N-type CCB, is linked to a reduced occurrence of pedal edema compared to amlodipine, which solely blocks L-type calcium channels. The antihypertensive properties of cilnidipine are very substantial, with low BP variability and long-acting properties. It is beneficial for hypertensive patients to deal with morning hypertension and for patients with abnormal nocturnal BP due to exaggerated sympathetic nerve activation. Besides its BP-lowering effect, it also exhibits organ protection via sympathetic nerve inhibition and renin-angiotensin-aldosterone system inhibition; it controls heart rate and proteinuria. Reno-protective, neuroprotective, and cardioprotective effects of cilnidipine have been well-documented and demonstrated.

Calcium channel blockers in patients with pulmonary arterial hypertension receiving PAH-specific treatment.

BACKGROUND: Calcium channel blockers (CCB) are the first effective therapy for vasoreactive patients with idiopathic pulmonary arterial hypertension (IPAH). However, the advent of modern PAH-specific drugs may undermine the role of vasoreactivity tests and CCB treatment. We aimed to clarify the effect of acute vasoreactivity testing and CCB on patients with IPAH receiving PAH-specific treatment. METHODS: We retrospectively investigated consecutive patients with IPAH (n = 136) diagnosed between 2000 and 2020 and collected data from patients who underwent acute vasoreactivity testing using inhaled nitric oxide (NO). The effects of vasoreactivity testing and CCB therapy were reviewed. Long-term survival was analysed using the Kaplan-Meier method. RESULTS: Acute vasoreactivity testing was performed in 49% of patients with IPAH (n = 67), including 23 patients (34%) receiving PAH-specific therapy without vasoreactivity testing. Eight patients (12%), including three patients (4.4%) receiving PAH-specific therapy, presented acute responses at vasoreactivity testing. They received high-dose CCB therapy (CCB monotherapy for five patients [7.5%] and CCB therapy and PAH-specific therapy for three patients [4.4%]). They presented a significant improvement in clinical parameters and near-normalisation of haemodynamics (mean pulmonary arterial pressure decreased from 46 [interquartile range: 40-49] to 19.5 [interquartile range: 18-23] mmHg [P < .001] at 1-year follow-up). All eight vasoreactive responders receiving CCB therapy showed better long-term survival than non-responders treated with PAH-specific therapy (P < .001). CONCLUSIONS: CCB therapy benefited patients with IPAH who showed acute response to vasoreactivity testing using inhaled NO, even when receiving modern PAH-specific therapy. Acute vasoreactive responders may benefit more from CCB than from PAH-specific therapy.

Trends of Antihypertensive Prescription Among US Adults From 2010 to 2019 and Changes Following Treatment Guidelines: Analysis of Multicenter Electronic Health Records.

BACKGROUND: Guidelines for the use of antihypertensives changed in 2014 and 2017. To understand the effect of these guidelines, we examined trends in antihypertensive prescriptions in the United States from 2010 to 2019 using a repeated cross-sectional design. METHODS AND RESULTS: Using electronic health records from 15 health care institutions for adults (20-85 years old) who had ≥1 antihypertensive prescription, we assessed whether (1) prescriptions of beta blockers decreased after the 2014 Eighth Joint National Committee (JNC 8) report discouraged use for first-line treatment, (2) prescriptions for calcium channel blockers and thiazide diuretics increased among Black patients after the JNC 8 report encouraged use as first-line therapy, and (3) prescriptions for dual therapy and fixed-dose combination among patients with blood pressure ≥140/90 mm Hg increased after recommendations in the 2017 Hypertension Clinical Practice Guidelines. The study included 1 074 314 patients with 2 133 158 prescription episodes. After publication of the JNC 8 report, prescriptions for beta blockers decreased (3% lower in 2018-2019 compared to 2010-2014), and calcium channel blockers increased among Black patients (20% higher in 2015-2017 and 41% higher in 2018-2019, compared to 2010-2014), in accordance with guideline recommendations. However, contrary to guidelines, dual therapy and fixed-dose combination decreased after publication of the 2017 Hypertension Clinical Practice Guidelines (9% and 11% decrease in 2018-2019 for dual therapy and fixed-dose combination, respectively, compared to 2015-2017), and thiazide diuretics decreased among Black patients after the JNC 8 report (6% lower in 2018-2019 compared to 2010-2014). CONCLUSIONS: Adherence to guidelines on prescribing antihypertensive medication was inconsistent, presenting an opportunity for interventions to achieve better blood pressure control in the US population.

Polygenic scores for cardiovascular risk factors improve estimation of clinical outcomes in CCB treatment compared to pharmacogenetic variants alone.

Pharmacogenetic variants are associated with clinical outcomes during Calcium Channel Blocker (CCB) treatment, yet whether the effects are modified by genetically predicted clinical risk factors is unknown. We analyzed 32,000 UK Biobank participants treated with dihydropiridine CCBs (mean 5.9 years), including 23 pharmacogenetic variants, and calculated polygenic scores for systolic and diastolic blood pressures, body fat mass, and other patient characteristics. Outcomes included treatment discontinuation and heart failure. Pharmacogenetic variant rs10898815-A (NUMA1) increased discontinuation rates, highest in those with high polygenic scores for fat mass. The RYR3 variant rs877087 T-allele alone modestly increased heart failure risks versus non-carriers (HR:1.13, p = 0.02); in patients with high polygenic scores for fat mass, lean mass, and lipoprotein A, risks were substantially elevated (HR:1.55, p = 4 × 10-5). Incorporating polygenic scores for adiposity and lipoprotein A may improve risk estimates of key clinical outcomes in CCB treatment such as treatment discontinuation and heart failure, compared to pharmacogenetic variants alone.

Discovery and Structure-Activity Relationship of a Ryanodine Receptor 2 Inhibitor.

Ryanodine receptor 2 (RyR2) is a large Ca2+-release channel in the sarcoplasmic reticulum (SR) of cardiac muscle cells. It serves to release Ca2+ from the SR into the cytosol to initiate muscle contraction. RyR2 overactivation is associated with arrhythmogenic cardiac disease, but few specific inhibitors have been reported so far. Here, we identified an RyR2-selective inhibitor 1 from the chemical compound library and synthesized it from glycolic acid. Synthesis of various derivatives to investigate the structure-activity relationship of each substructure afforded another two RyR2-selective inhibitors 6 and 7, among which 6 was the most potent. Notably, compound 6 also inhibited Ca2+ release in cells expressing the RyR2 mutants R2474S, R4497C and K4750Q, which are associated with cardiac arrhythmias such as catecholaminergic polymorphic ventricular tachycardia (CPVT). This inhibitor is expected to be a useful tool for research on the structure and dynamics of RyR2, as well as a lead compound for the development of drug candidates to treat RyR2-related cardiac disease.

Nimodipine prophylaxis in aneurysmal subarachnoid hemorrhage, a question of tradition or evidence: A scoping review.

BACKGROUND: The prophylactic use of nimodipine following subarachnoid hemorrhage is a practice established four decades ago when clinical management differed from current and the concept of Delayed Cerebral Ischemia (DCI) was not established. The applicability of the original studies is limited by the fact of not reflecting current practice; by utilising a dichotomised outcome measure such as good neurological outcome versus death and vegetative state; by applying variable dosing regimens and including all causes of poor neurological outcome different than DCI. This study aims to review the available evidence to discuss the ongoing role of nimodipine in contemporaneous clinical practice. METHODS: PRISMA guidelines based review, evaluated the evidence on the prophylactic use of nimodipine. The following search engines: Medline, Embase, Cochrane, Web of Science and PubMed, identified Randomized Control Trials (RCTs) with neurological benefit as outcome measure and the impact of fixed versus weight-based nimodipine dosing regimens. RESULTS: Eight RCT were selected. Three of those trials with a total of 349 patients, showed a reduction on death and vegetative state (pooled RR: 0.62; 95 % confidence interval-CI: 0.45, 0.86) related to DCI. Amongst all studies, all cause death (pooled RR = 0.73, [95 % CI: 0.56, 0.97]) favoured a fixed-dose regimen (pooled RR: 0.60; [95 % CI: 0.43, 0.85]). CONCLUSION: Available evidence demonstrates that nimodipine only reduces the risk for DCI-related death or vegetative state and that fixed-dose regimens favour all cause infarct and death independent of DCI. Contemporaneous studies assessing the benefit of nimodipine beyond death or vegetative states and applying individualized dosing are warranted.

The current position of ß-blockers in hypertension: guidelines and clinical practice.

The benefits of improved clinical outcomes through blood pressure (BP) reduction have been proven in multiple clinical trials and meta-analyses. The new (2023) guideline from the European Society of Hypertension (ESH) includes ß-blockers within five main classes of antihypertensive agents suitable for initiation of antihypertensive pharmacotherapy and for combination with other antihypertensive agents. This is in contrast to the 2018 edition of ESH guidelines that recommended ß-blockers for use primarily in patients with compelling indications such as cardiovascular comorbidities, e.g. coronary heart disease, heart failure. This change was based on the fact that the magnitude of BP reduction is the most important factor for adverse cardiovascular outcomes, over and above the precise manner in which reduced BP is achieved. The ESH guideline also supports the use of ß-blockers for patients with resting heart rate (>80 bpm); high resting heart rate is a sign of sympathetic overactivity, an important driver of adverse cardiac remodelling in the setting of hypertension and heart failure. Hypertension management guidelines support for the use of combination therapies for almost all patients with hypertension, ideally within a single-pill combination to optimise adherence to therapy. Where a ß-blocker is prescribed, the inclusion of a dihydropyridine calcium channel blocker within a combination regimen is rational. These agents together reduce both peripheral and central BP, which epidemiological studies have shown is important for reducing the burden of premature morbidity and mortality associated with uncontrolled hypertension, especially strokes.

Brain-derived neurotrophic factor scales presynaptic calcium transients to modulate excitatory neurotransmission.

Brain-derived neurotrophic factor (BDNF) plays a critical role in synaptic physiology, as well as mechanisms underlying various neuropsychiatric diseases and their treatment. Despite its clear physiological role and disease relevance, BDNF's function at the presynaptic terminal, a fundamental unit of neurotransmission, remains poorly understood. In this study, we evaluated single synapse dynamics using optical imaging techniques in hippocampal cell cultures. We find that exogenous BDNF selectively increases evoked excitatory neurotransmission without affecting spontaneous neurotransmission. However, acutely blocking endogenous BDNF has no effect on evoked or spontaneous release, demonstrating that different approaches to studying BDNF may yield different results. When we suppressed BDNF-Tropomyosin receptor kinase B (TrkB) activity chronically over a period of days to weeks using a mouse line enabling conditional knockout of TrkB, we found that evoked glutamate release was significantly decreased while spontaneous release remained unchanged. Moreover, chronic blockade of BDNF-TrkB activity selectively downscales evoked calcium transients without affecting spontaneous calcium events. Via pharmacological blockade by voltage-gated calcium channel (VGCC) selective blockers, we found that the changes in evoked calcium transients are mediated by the P/Q subtype of VGCCs. These results suggest that BDNF-TrkB activity increases presynaptic VGCC activity to selectively increase evoked glutamate release.

Comparison between beta-blockers and calcium channel blockers in patients with atrial fibrillation according to renal function.

BACKGROUND: Rate control is the most commonly employed first-line management strategy for atrial fibrillation (AF) in patients with chronic kidney disease (CKD). Principal agents used to control heart rate (HR) include beta-blockers (BB) and nondihydropyridine calcium channel blockers (ND-CCB). However, there is a paucity of published studies of the differences between those drugs in CKD patients. HYPOTHESIS: The present study aimed to investigate the differences, in terms of hospitalizations due to a poor HR control, in patients with AF under a rate-control strategy according to glomerular filtration rate (GFR). METHODS: The study cohort included 2804 AF patients under rate-control regime (BB or ND-CCB) between January 2014 and April 2020. The end point, determined by competing risk regression, was hospitalizations for AF with rapid ventricular response (RVR), slow ventricular response (SVR), and need for pacemaker. RESULTS: On multivariate analysis, there were no statistical differences between ND-CCB and BB for subjects with GFR > 60 mL/min/1.73 m2 (subdistribution heart rate [sHR] 0.850, 95% confidence interval [CI]: 0.61-1.19; p = .442) and GFR 30-59 mL/min/1.73 m2 (sHR 1.242, 95% CI: 0.80-1.63; p = .333), while in patients with GFR < 30 mL/min/1.73 m2, ND-CCB therapy was associated with increased hospitalizations due to poor HR control (sHR 4.53, 95% CI: 1.19-17.18; p = .026). CONCLUSION: In patients with GFR ≥ 30 mL/min/1.73 m2, the choice of ND-CCB or BB had no impact on hospitalizations due to poor HR control, while in GFR < 30 mL/min/1.73 m2, a possible association was detected. The effects of these drugs on GFR < 30 mL/min/1.73 m2 would require further investigation.

Enteropathy and intestinal malabsorption in patients treated with antihypertensive drugs. A retrospective cohort study.

OBJECTIVES: To investigate differences in the incidence of enteropathy or intestinal malabsorption in patients taking angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitor (ACEI), calcium channel blocker (CCB), and beta blockers (BBs) at a single center in Korea. METHODS: In this retrospective study, we utilized data from the Yangsan electronic medical records to identify 129,169 patients. These individuals were prescribed olmesartan, other ARBs, ACEI, CCB, and BBs between November 2008 and February 2021. RESULTS: Of the 44,775 patients, 51 (0.11%) were observed to have enteropathy or intestinal malabsorption. Compared with the ACEI group, the adjusted odds ratios (ORs) for enteropathy and intestinal malabsorption were OR=1.313 (95% confidence interval [CI]: [0.188-6.798], p=0.893) for olmesartan, OR=0.915 (95% CI: [0.525-1.595], p=0.754) for the other ARBs, OR=0.928 (95% CI: [0.200-4.307]; p=0.924) for the CCB, and OR=0.663 (95% CI: [0.151-2.906]; p=0.586) for the BBs group. These findings were adjusted for factors such as age, gender, duration of antihypertensive medication, and comorbidities. CONCLUSION: In a retrospective cohort study of patients on antihypertensive medications, no significant difference was found in the incidence of enteropathy or intestinal malabsorption when ACEI was compared to olmesartan, other ARBs, CCB, and BBs.

The clinical value of ß-blockers in patients with stable angina.

Stable angina, one manifestation of chronic coronary syndrome (CCS), is characterised by intermittent episodes of insufficient blood supply to the myocardium, provoking symptoms of myocardial ischaemia, particularly chest pain. These attacks usually occur during exercise or stress. Anti-ischaemic drugs are the mainstay of pharmacologic management of CCS with symptoms of angina. ß-blockers reduce heart rate and myocardial contractility, thus reducing myocardial oxygen consumption. These drugs have been shown to ameliorate the frequency of anginal attacks and to improve exercise capacity in these patients. Current management guidelines include ß-blockers as a first-line management option for most patients with CCS and symptoms of myocardial ischaemia, alongside dihydropyridine calcium channel blockers (CCB). The presence of comorbid angina and heart failure is a strong indication for starting with a ß-blocker. ß-blockers are also useful in the management of angina symptoms accompanied by a high heart rate, hypertension (with or without a renin-angiotensin-aldosterone-system [RAS] blocker or CCB), or microvascular angina (with a RAS blocker and a statin). A ß-blocker is not suitable for a patient with low heart rate (<50 bpm), although use of a ß-blocker may be supported by a pacemaker if the ß-blocker is strongly indicated) and should be used at a low dose only in patients with low blood pressure.

5-Hydroxytryptamine Enhances the Pacemaker Activity of Interstitial Cells of Cajal in Mouse Colon.

We examined the localization of the 5-hydroxytryptamine (5-HT) receptor and its effects on mouse colonic interstitial cells of Cajal (ICCs) using electrophysiological techniques. Treatment with 5-HT increased the pacemaker activity in colonic ICCs with depolarization of membrane potentials in a dose-dependent manner. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blockers blocked pacemaker activity and 5-HT-induced effects. Moreover, an adenylate cyclase inhibitor inhibited 5-HT-induced effects, and cell-permeable 8-bromo-cAMP increased the pacemaker activity. Various agonists of the 5-HT receptor subtype were working in colonic ICCs, including the 5-HT4 receptor. In small intestinal ICCs, 5-HT depolarized the membrane potentials transiently. Adenylate cyclase inhibitors or HCN blockers did not show any influence on 5-HT-induced effects. Anoctamin-1 (ANO1) or T-type Ca2+ channel blockers inhibited the pacemaker activity of colonic ICCs and blocked 5-HT-induced effects. A tyrosine protein kinase inhibitor inhibited pacemaker activity in colonic ICCs under controlled conditions but did not show any influence on 5-HT-induced effects. Among mitogen-activated protein kinase (MAPK) inhibitors, a p38 MAPK inhibitor inhibited 5-HT-induced effects on colonic ICCs. Thus, 5-HT's effect on pacemaker activity in small intestinal and colonic ICCs has excitatory but variable patterns. ANO1, T-type Ca2+, and HCN channels are involved in 5-HT-induced effects, and MAPKs are involved in 5-HT effects in colonic ICCs.

Novel protocol for multiple-dose oral administration of the L-type Ca2+ channel blocker isradipine in mice: A dose-finding pharmacokinetic study.

Studies in genetically modified animals and human genetics have recently provided new insight into the role of voltage-gated L-type Ca2+ channels in human disease. Therefore, the inhibition of L-type Ca2+ channels in vivo in wildtype and mutant mice by potent dihydropyridine (DHP) Ca2+ channel blockers serves as an important pharmacological tool. These drugs have a short plasma half-life in humans and especially in rodents and show high first-pass metabolism upon oral application. In the vast majority of in vivo studies, they have therefore been delivered through parenteral routes, mostly subcutaneously or intraperitoneally. High peak plasma concentrations of DHPs cause side effects, evident as DHP-induced aversive behaviors confounding the interpretation of behavioral readouts. Nevertheless, pharmacokinetic data measuring the exposure achieved with these applications are sparse. Moreover, parenteral injections require animal handling and can be associated with pain, discomfort and stress which could influence a variety of physiological processes, behavioral and other functional readouts. Here, we describe a noninvasive oral application of the DHP isradipine by training mice to quickly consume small volumes of flavored yogurt that can serve as drug vehicle. This procedure does not require animal handling, allows repeated drug application over several days and reproducibly achieves peak plasma concentrations over a wide range previously shown to be well-tolerated in humans. This protocol should facilitate ongoing nonclinical studies in mice exploring new indications for DHP Ca2+ channel blockers.

Amlodipine inhibits Synaptotagmin-4's oncogenic activity on gastric cancer proliferation by targeting calcium signaling.

BACKGROUND: Gastric cancer (GC) remains a leading cause of cancer mortality globally. Synaptotagmin-4 (SYT4), a calcium-sensing synaptic vesicle protein, has been implicated in the oncogenesis of diverse malignancies. PURPOSE: This study delineates the role of SYT4 in modulating clinical outcomes and biological behaviors in GC. METHODS: We evaluated SYT4 expression in GC specimens using bioinformatics analyses and immunohistochemistry. Functional assays included CCK8 proliferation tests, apoptosis assays via flow cytometry, confocal calcium imaging, and xenograft models. Western blotting elucidated MAPK pathway involvement. Additionally, we investigated the impact of the calcium channel blocker amlodipine on cellular dynamics and MAPK pathway activity. RESULTS: SYT4 was higher in GC tissues, and the elevated SYT4 was significantly correlated with adverse prognosis. Both univariate and multivariate analyses confirmed SYT4 as an independent prognostic indicator for GC. Functionally, SYT4 promoted tumorigenesis by fostering cellular proliferation, inhibiting apoptosis, and enhancing intracellular Ca2+ influx, predominantly via MAPK pathway activation. Amlodipine pre-treatment attenuated SYT4-driven cell growth and potentiated apoptosis, corroborated by in vivo xenograft assessments. These effects were attributed to MAPK pathway suppression by amlodipine. CONCLUSION: SYT4 emerges as a potential prognostic biomarker and a pro-oncogenic mediator in GC through a Ca2+-dependent MAPK mechanism. Amlodipine demonstrates significant antitumor effects against SYT4-driven GC, positing its therapeutic promise. This study underscores the imperative of targeting calcium signaling in GC treatment strategies.

For Debate: The 2023 European Society of Hypertension guidelines - cause for concern.

Originally, the beta-blockers were equally ranked alongside the other antihypertensive drug classes. Things changed when two major long-term randomized controlled trials, ASCOT-BPLA and LIFE showed that the patients receiving the beta-blockers based regimes suffered 25-30% more strokes than those receiving a calcium channel blocker based regime or an angiotensin receptor blocker based regime. The inferiority of the beta-blockers at stroke prevention was not due to differences in blood pressure control during the follow-up period in both trials. The 2023 European Society of Hypertension (ESH) guidelines still argue in favour of beta-blockers that their clinical inferiority was simply to lesser blood pressure reduction rather than class effect. The analysis argues that the return of beta-blockers as a first-line option for the management of uncomplicated hypertension by the ESH is a cause for concern and should be reconsidered.