Parabrachial Calca neurons drive nociplasticity

Pain that persists beyond the time required for tissue healing and pain that arises in the absence of tissue injury, collectively referred to as nociplastic pain, are poorly understood phenomena mediated by plasticity within the central nervous system. The parabrachial nucleus (PBN) is a hub that relays aversive sensory information and appears to play a role in nociplasticity. Here, by preventing PBN Calca neurons from releasing neurotransmitters, we demonstrate that activation of Calca neurons is necessary for the manifestation and maintenance of chronic pain. Additionally, by directly stimulating Calca neurons, we demonstrate that Calca neuron activity is sufficient to drive nociplasticity. Aversive stimuli of multiple sensory modalities, such as exposure to nitroglycerin, cisplatin, or lithium chloride, can drive nociplasticity in a Calca-neuron-dependent manner. Aversive events drive nociplasticity in Calca neurons in the form of increased activity and excitability; however, neuroplasticity also appears to occur in downstream circuitry.

Models of Trigeminal Activation: Is There an Animal Model of Migraine?

Migraine, recognized as a severe headache disorder, is widely prevalent, significantly impacting the quality of life for those affected. This article aims to provide a comprehensive review of the application of animal model technologies in unraveling the pathomechanism of migraine and developing more effective therapies. It introduces a variety of animal experimental models used in migraine research, emphasizing their versatility and importance in simulating various aspects of the condition. It details the benefits arising from the utilization of these models, emphasizing their role in elucidating pain mechanisms, clarifying trigeminal activation, as well as replicating migraine symptoms and histological changes. In addition, the article consciously acknowledges the inherent limitations and challenges associated with the application of animal experimental models. Recognizing these constraints is a fundamental step toward fine-tuning and optimizing the models for a more accurate reflection of and translatability to the human environment. Overall, a detailed and comprehensive understanding of migraine animal models is crucial for navigating the complexity of the disease. These findings not only provide a deeper insight into the multifaceted nature of migraine but also serve as a foundation for developing effective therapeutic strategies that specifically address the unique challenges arising from migraine pathology.

Differences in Neuropathology between Nitroglycerin-Induced Mouse Models of Episodic and Chronic Migraine

Multiple animal models of migraine have been used to develop new therapies. Understanding the transition from episodic (EM) to chronic migraine (CM) is crucial. We established models mimicking EM and CM pain and assessed neuropathological differences. EM and CM models were induced with single NTG or multiple injections over 9 days. Mechanical hypersensitivity was assessed. Immunofluorescence utilized c-Fos, NeuN, and Iba1. Proinflammatory and anti-inflammatory markers were analyzed. Neuropeptides (CGRP, VIP, PACAP, and substance P) were assessed. Mechanical thresholds were similar. Notable neuropathological distinctions were observed in Sp5C and ACC. ACC showed increased c-Fos and NeuN expression in CM (p < 0.001) and unchanged in EM. Sp5C had higher c-Fos and NeuN expression in EM (p < 0.001). Iba1 was upregulated in Sp5C of EM and ACC of CM (p < 0.001). Proinflammatory markers were strongly expressed in Sp5C of EM and ACC of CM. CGRP expression was elevated in both regions and was higher in CM. VIP exhibited higher levels in the Sp5C of EM and ACC of CM, whereas PACAP and substance P were expressed in the Sp5C in both models. Despite similar thresholds, distinctive neuropathological differences in Sp5C and ACC between EM and CM models suggest a role in the EM to CM transformation.

Arterial stiffness of the aorta and iliofemoral artery and their responses to nitroglycerin administration in myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits

OBJECTIVES

The role of hypercholesterolemia in arterial stiffness, which usually reflects the progression of atherosclerosis has not been fully investigated. To clarify the meaning of arterial stiffness in hypercholesterolemia, we evaluated arterial stiffness in myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits by using new arterial stiffness indices of the aorta and common iliac to femoral artery. The new arterial stiffness indices of both arteries were determined by the application of the theory of cardio-ankle vascular index (CAVI) to the aorta (aBeta) and ilio-femoral artery (ifBeta). Furthermore, the responses of both indices to nitroglycerin (NTG) administration were compared between WHHHMI and normal rabbits.

DESIGN AND METHODS

aBeta and ifBeta of WHHLMI and normal rabbits were measured under anesthesia. Pulse wave velocity in the whole aorta (aPWV) and ilio-femoral artery (ifPWV), blood pressure, and other parameters were measured before and after administration of NTG (50-120 μg/kg/min) every 1 for 5 min.

RESULTS

Atherosclerotic lesions were observed in the aorta, but a little in the ilio-femoral artery in WHHLMI rabbits. Compared with normal rabbits, aBeta was significantly higher, but ifBeta was lower in WHHLMI rabbits. When NTG was administered, ifBeta decreased significantly in both groups; however, aBeta increased in normal rabbits, but remained unchanged in WHHIMI rabbits.

CONCLUSION

These findings suggested that hereditary hypercholesterolemia in rabbits did not uniformly enhance arterial stiffness in elastic artery and muscular artery. The responses to NTG were also different between two arteries. The mechanism of these different responses needs further studies.

Comparison of the effects of dexmedetomidine and nitroglycerin on cerebral oxygen saturation using near-infrared spectroscopy in patients undergoing controlled hypotensive anaesthesia: A randomised controlled non-inferiority trial

Background and Aims

There is limited literature wherein the hypotensive drugs have been compared to know the cerebral effects by monitoring regional cerebral oxygen saturation (rScO2). This study aimed to compare the effects of dexmedetomidine and nitroglycerin on rScO2 during controlled hypotensive anaesthesia using near-infrared spectroscopy (NIRS). The primary objective was to evaluate the non-inferiority of dexmedetomidine versus nitroglycerin in the occurrence of cerebral desaturation events (CDEs) during hypotensive anaesthesia.

Methods

Adult patients scheduled to undergo head and neck surgery under general anaesthesia randomised to receive either dexmedetomidine or nitroglycerin infusion for controlled hypotensive anaesthesia. Cerebral oximetry was monitored with NIRS, and data regarding CDEs, bilateral rScO2, and peri-operative haemodynamics were collected. Continuous data were analysed using unpaired Student's t-tests except for intra-group analyses, which were analysed using paired t-tests. Categorical data were analysed using the Chi-square test. For comparison of time to CDEs, Kaplan-Meier survival analysis with log-rank test was performed.

Results

Of the 82 patients in both groups, CDEs were observed in 15 patients each. A decrease from baseline by 20% was observed in three patients: one in Group N and two in Group D. Statistically, there was an equal risk of getting CDEs in the groups. The time to CDE was comparable (P > 0.05). The difference in heart rate was statistically significant (P < 0.001).

Conclusion

Dexmedetomidine is non-inferior to nitroglycerin in terms of the occurrence of cerebral desaturation events when used for controlled hypotensive anaesthesia in head and neck surgeries.

Nitroglycerin to Ameliorate Coronary Artery Spasm During Focal Pulsed-Field Ablation for Atrial Fibrillation

BACKGROUND

In treating atrial fibrillation, pulsed-field ablation (PFA) has comparable efficacy to conventional thermal ablation, but with important safety advantages: no esophageal injury or pulmonary vein stenosis, and rare phrenic nerve injury. However, when PFA is delivered in proximity to coronary arteries using a pentaspline catheter, which generates a broad electrical field, severe vasospasm can be provoked.

OBJECTIVES

The authors sought to study the vasospastic potential of a focal PFA catheter with a narrower electrical field and develop a preventive strategy with nitroglycerin.

METHODS

During atrial fibrillation ablation, a focal PFA catheter was used for cavo-tricuspid isthmus ablation. Angiography of the right coronary artery (some with fractional flow reserve measurement) was performed before, during, and after PFA. Beyond no nitroglycerin (n = 5), and a few testing strategies (n = 8), 2 primary nitroglycerin administration strategies were studied: 1) multiple boluses (3-2 mg every 2 min) into the right atrium (n = 10), and 2) a bolus (3 mg) into the right atrium with continuous peripheral intravenous infusion (1 mg/min; n = 10).

RESULTS

Without nitroglycerin, cavo-tricuspid isthmus ablation provoked moderate-severe vasospasm in 4 of 5 (80%) patients (fractional flow reserve 0.71 ± 0.08). With repetitive nitroglycerin boluses, severe spasm did not occur, and mild-moderate vasospasm occurred in only 2 of 10 (20%). Using the bolus + infusion strategy, severe and mild-moderate spasm occurred in 1 and 3 of 10 patients (aggregate 40%). No patient had ST-segment changes.

CONCLUSIONS

Ablation of the cavotricuspid isthmus using a focal PFA catheter routinely provokes right coronary vasospasm. Pretreatment with high doses of parenteral nitroglycerin prevents severe spasm.

Distal Radial Approach in Coronary Angiography Using a Transdermal Nitroglycerin Patch: Double-Blinded Randomized Trial

Nitroglycerin dilates the radial artery and prevents spasm, which increases the success rate of sheath cannulation through the conventional transradial approach. However, the effects of nitroglycerin on distal radial approach (DRA) procedures are not known. The aim of this study is to elucidate whether a transdermal nitroglycerin patch improves the rate of successful DRA cannulation. A total of 92 patients scheduled for coronary angiography by means of DRA randomly received (1:1) a transdermal nitroglycerin patch preintegrated with the covering material or only the covering material on their upper arm on the side of the puncture. The diameter of the distal radial artery was evaluated with ultrasound at baseline and after application. DRA procedures were performed in a double-blind fashion. The primary outcome was the rate of successful palpation-guided distal radial artery cannulation with the first puncture. The nitroglycerin group had larger distal radial artery diameter after patch application than that of the no-treatment group (mean, 3.21 mm vs 2.71 mm, p <0.001), but not at baseline (mean, 2.64 mm vs 2.64 mm, p = 0.965).The nitroglycerin group had a significantly higher success rate of DRA cannulation with the first puncture than that of the no-treatment group (59% vs 24%, p = 0.001; odds ratio 4.5, 95% confidence interval 1.9 to 11.0). The nitroglycerin group required fewer punctures than did the no-treatment group (median, 1 vs 3, p = 0.019). There were no significant differences in the occurrence of hypotension between the 2 groups. No patients experienced radial artery occlusion. In conclusion, transdermal nitroglycerin patch application safely facilitates DRA cannulation. Trial Registration: Japan Registry of Clinical Trials, https://jrct.niph.go.jp/ (identifier: jRCTs051210128).

Comparative study of piroxicam and nitroglycerin on prostaglandin-modulated blood and electrolyte indices during di-estrous in female Wistar Rats

OBJECTIVE

Endogenous prostaglandins are involved in hemostasis, renal excretion of electrolytes, and implicated in dysmenorrhea. Piroxicam and Nitroglycerin are common drugs used in treating dysmenorrhea by inhibiting the cyclooxygenase pathway involved in prostaglandin production. However, studies comparing the effects of these drugs on prostaglandin-modulated hemostasis and renal function are lacking.

METHODS

Fifteen female rats (120-160g) were divided into 3 groups (20 per group), namely Control (distilled water, 0.3 mL), Piroxicam treated (3mg/kg) and Nitroglycerin treated (1 mg/kg). Di-estrous phase was confirmed in animals in each group using the Pipette smear method. Treatment was administered for 4 days covering the estrous cycle. Bleeding and clotting time were assessed and blood concentrations of sodium, potassium, urea and platelet counts were evaluated in all phases. Data were analyzed using one-way ANOVA and Newman-Keuls post-hoc test. Statistical significance was considered at p<0.0.

RESULTS

The nitroglycerin-treated group showed significant increases in blood potassium during di-estrous while the piroxicam-treated group showed significant increases in blood potassium, urea and clotting time with a significant decrease in sodium levels during di-estrous compared to controls. Results obtained in other phases were not significant compared to controls.

CONCLUSIONS

The study showed that Nitroglycerin produces minimum alteration of blood and electrolyte indices compared to piroxicam during di-estrous.

Preserved endothelium-independent vascular function with aging in men and women: evidence from the peripheral and cerebral vasculature

In the peripheral and cerebral vasculature, the impact of aging and sex on the endothelial-independent functional capacity of vascular smooth muscle cells (VSMCs) is not well understood, nor is it known whether such VSMC functions in these vascular beds reflect one another. Therefore, endothelium-independent dilation, at both the conduit (Δ diameter) and microvascular (Δ vascular conductance, VC) level, elicited by sublingual nitroglycerin (NTG, 0.8 mg of Nitrostat), compared with sham-delivery (control), was assessed using Doppler ultrasound in the popliteal (PA) and middle cerebral (MCA) artery of 20 young [23 ± 4 yr, 10 males (YM)/10 females (YF)] and 21 old [69 ± 5 yr, 11 males (OM)/10 females (OF)] relatively healthy adults. In the PA, compared with zero, NTG significantly increased diameter in all groups (YM: 0.29 ± 0.13, YF: 0.35 ± 0.26, OM: 0.30 ± 0.18, OF: 0.31 ± 0.14 mm), while control did not. The increase in VC only achieved significance in the OF (0.22 ± 0.31 mL/min/mmHg). In the MCA, compared with zero, NTG significantly increased diameter and VC in all groups (YM: 0.89 ± 0.30, 1.06 ± 1.28; YF: 0.97 ± 0.31, 1.84 ± 1.07; OM: 0.90 ± 0.42, 0.72 ± 0.99; OF: 0.74 ± 0.32, 1.19 ± 1.18, mm and mL/min/mmHg, respectively), while control did not. There were no age or sex differences or age-by-sex interactions for both the NTG-induced PA and MCA dilation and VC. In addition, PA and MCA dilation and VC responses to NTG were not related when grouped by age, sex, or as all subjects (r = 0.04-0.44, P > 0.05). Thus, peripheral and cerebral endothelial-independent VSMC function appears to be unaffected by age or sex, and variations in such VSMC function in one of these vascular beds are not reflected in the other.NEW & NOTEWORTHY To confidently explain peripheral and cerebral vascular dysfunction, it is essential to have a clear understanding of the endothelial-independent function of VSMCs across age and sex. By assessing endothelium-independent dilation using sublingual nitroglycerin, endothelial-independent VSMC function in the periphery (popliteal artery), and in the cerebral circulation (middle cerebral artery), was not different due to age or sex. In addition, endothelial-independent VSMC function in one of these vascular beds is not reflected in the other.

Case report: A combination of nitroglycerin and adenosine proves effective in repairing a cerebral arteriovenous malformation

Hemorrhage secondary to rupture of a brain arteriovenous malformations (AVM) is one of the initial manifestations, and the main cause of, morbidity and mortality in patients with this condition. Current treatment strategies include endovascular embolization with the goal of AVM obliteration and neurological preservation. In the transvenous endovascular embolization procedure, adenosine is the preferred agent to induce temporary hypotension and allow adequate AVM embolization. We describe the intraoperative management of an adenosine-resistant 38 year-old male who underwent a successful intracranial AVM embolization after concomitant administration of gradually increasing doses of nitroglycerin. This report suggests that nitroglycerin infusion can be combined with adenosine boluses to create a pronounced and dose-dependent hypotension in patients partially unresponsive to adenosine alone.

The Impact of Nitroglycerin on the Evaluation of Coronary Stenosis in Coronary-CT: Preliminary Study in 131 Patients

BACKGROUND

The sublingual administration of short-acting nitroglycerin (NTG) before coronary computed tomography (CCT) improves the visualization of coronary arteries, causing vasodilatation. The aim of this study was to evaluate whether and how nitroglycerin can influence the concordance between radiologists and cardiologists in the evaluation of vessel stenosis measured in CCT by the former and during the following coronarography by the latter.

METHODS

We conducted a retrospective analysis of 131 patients who underwent CCT for cardiac symptoms in 2022, followed by coronarography performed six months later because of significant stenosis revealed by the CCT. First, the patients were divided into two groups: an NTG group who received sublingual nitroglycerin before CCT and a non-NTG group who did not because of contraindications. Second, 254 stenoses were measured by two radiologists after CCT and by two interventional cardiologists during the next coronarography; moreover, stenoses were classified on the basis of their location and plaque pattern (calcific, mixed and lipidic). Third, the strength of agreement was evaluated between the two radiologists, between the two cardiologists and finally between the radiologists and cardiologists in order to evaluate whether and how the interdisciplinary discrepancy in stenosis evaluation could change with or without the use of nitroglycerin before CCT and in relation to the different plaque pattern.

RESULTS

In the NTG group, the use of nitroglycerine reduced the agreement between radiologists and cardiologists in calcific stenosis but did not change the concordance in the case of mixed or lipidic plaques on the same vessels.

CONCLUSIONS

The use of sublingual nitroglycerin before CCT may lead to a radiological overestimation of calcific stenosis.

Effects of Fumarate and Nitroglycerin on In Vitro Rumen Fermentation, Methane and Hydrogen Production, and on Microbiota

This study aimed to investigate the effects of fumarate and nitroglycerin on rumen fermentation, methane and hydrogen production, and microbiota. In vitro rumen fermentation was used in this study with four treatment groups: control (CON), fumarate (FA), nitroglycerin (NG) and fumarate plus nitroglycerin (FN). Real-time PCR and 16S rRNA gene sequencing were used to analyze microbiota. The results showed that nitroglycerin completely inhibited methane production and that this resulted in hydrogen accumulation. Fumarate decreased the hydrogen accumulation and improved the rumen fermentation parameters. Fumarate increased the concentration of propionate and microbial crude protein, and decreased the ratio of acetate to propionate in FN. Fumarate, nitroglycerin and their combination did not affect the abundance of bacteria, protozoa and anaerobic fungi, but altered archaea. The PCoA showed that the bacterial (Anosim, R = 0.747, p = 0.001) and archaeal communities (Anosim, R = 0.410, p = 0.005) were different among the four treatments. Compared with CON, fumarate restored Bacteroidetes, Firmicutes, Spirochaetae, Actinobacteria, Unclassified Ruminococcaceae, Streptococcus, Treponema and Bifidobacterium in relative abundance in FN, but did not affect Succinivibrio, Ruminobacter and archaeal taxa. The results indicated that fumarate alleviated the depressed rumen fermentation caused by the inhibition of methanogenesis by nitroglycerin. This may potentially provide an alternative way to use these chemicals to mitigate methane emission in ruminants.

Interventions affecting the nitric oxide pathway versus placebo or no therapy for fetal growth restriction in pregnancy

BACKGROUND

Fetal growth restriction (FGR) is a condition of poor growth of the fetus in utero. One of the causes of FGR is placental insufficiency. Severe early-onset FGR at < 32 weeks of gestation occurs in an estimated 0.4% of pregnancies. This extreme phenotype is associated with a high risk of fetal death, neonatal mortality, and neonatal morbidity. Currently, there is no causal treatment, and management is focused on indicated preterm birth to prevent fetal death. Interest has risen in interventions that aim to improve placental function by administration of pharmacological agents affecting the nitric oxide pathway causing vasodilatation.

OBJECTIVES

The objective of this systematic review and aggregate data meta-analysis is to assess the beneficial and harmful effects of interventions affecting the nitric oxide pathway compared with placebo, no therapy, or different drugs affecting this pathway against each other, in pregnant women with severe early-onset FGR.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (16 July 2022), and reference lists of retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of interventions affecting the nitric oxide pathway compared with placebo, no therapy, or another drug affecting this pathway in pregnant women with severe early-onset FGR of placental origin, for inclusion in this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods for data collection and analysis.

MAIN RESULTS

We included a total of eight studies (679 women) in this review, all of which contributed to the data and analysis. The identified studies report on five different comparisons: sildenafil compared with placebo or no therapy, tadalafil compared with placebo or no therapy, L-arginine compared with placebo or no therapy, nitroglycerin compared with placebo or no therapy and sildenafil compared with nitroglycerin. The risk of bias of included studies was judged as low or unclear. In two studies the intervention was not blinded. The certainty of evidence for our primary outcomes was judged as moderate for the intervention sildenafil and low for tadalafil and nitroglycerine (due to low number of participants and low number of events). For the intervention L-arginine, our primary outcomes were not reported. Sildenafil citrate compared to placebo or no therapy (5 studies, 516 women) Five studies (Canada, Australia and New Zealand, the Netherlands, the UK and Brazil) involving 516 pregnant women with FGR were included. We assessed the certainty of the evidence as moderate. Compared with placebo or no therapy, sildenafil probably has little or no effect on all-cause mortality (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.80 to 1.27, 5 studies, 516 women); may reduce fetal mortality (RR 0.82, 95% CI 0.60 to 1.12, 5 studies, 516 women), and increase neonatal mortality (RR 1.45, 95% CI 0.90 to 2.33, 5 studies, 397 women), although the results are uncertain for fetal and neonatal mortality as 95% confidence intervals are wide crossing the line of no effect. Tadalafil compared with placebo or no therapy (1 study, 87 women) One study (Japan) involving 87 pregnant women with FGR was included. We assessed the certainty of the evidence as low. Compared with placebo or no therapy, tadalafil may have little or no effect on all-cause mortality (risk ratio 0.20, 95% CI 0.02 to 1.60, one study, 87 women); fetal mortality (RR 0.11, 95% CI 0.01 to 1.96, one study, 87 women); and neonatal mortality (RR 0.89, 95% CI 0.06 to 13.70, one study, 83 women). L-Arginine compared with placebo or no therapy (1 study, 43 women) One study (France) involving 43 pregnant women with FGR was included. This study did not assess our primary outcomes. Nitroglycerin compared to placebo or no therapy (1 studies, 23 women) One study (Brazil) involving 23 pregnant women with FGR was included. We assessed the certainty of the evidence as low. The effect on the primary outcomes is not estimable due to no events in women participating in both groups. Sildenafil citrate compared to nitroglycerin (1 study, 23 women) One study (Brazil) involving 23 pregnant women with FGR was included. We assessed the certainty of the evidence as low. The effect on the primary outcomes is not estimable due to no events in women participating in both groups.

AUTHORS' CONCLUSIONS

Interventions affecting the nitric oxide pathway probably do not seem to influence all-cause (fetal and neonatal) mortality in pregnant women carrying a baby with FGR, although more evidence is needed. The certainty of this evidence is moderate for sildenafil and low for tadalafil and nitroglycerin. For sildenafil a fair amount of data are available from randomised clinical trials, but with low numbers of participants. Therefore, the certainty of evidence is moderate. For the other interventions investigated in this review there are insufficient data, meaning we do not know whether these interventions improve perinatal and maternal outcomes in pregnant women with FGR.

Dose-response study of prophylactic nitroglycerin for prevention of pituitrin-induced hypertension during laparoscopic myomectomy: a prospective, randomized study

Objective

To determine the dose-response of nitroglycerin in preventing pituitrin-induced hypertension in patients undergoing laparoscopic myomectomy.

Methods

Hundred patients scheduled for elective laparoscopic myomectomy were randomly allocated into one of five groups (n = 20) to receive intravenous bolus of prophylactic nitroglycerin at 0, 50, 75, 100, and 125 μg one minute following administration of 3 IU of pituitrin into the myometrium. The patients were monitored for pituitrin-induced hypertension with the primary outcome to determine the effective dose of prophylactic nitroglycerin, defined as complete prevention of pituitrin-induced hypertension during the study period. Probit analysis was used to calculate the median effective dose (ED₅₀) and 95% effective dose (ED₉₅) of prophylactic nitroglycerin.

Results

Hypertension occurred in 19/20, 10/20, 8/20, 2/20, and 1/20 in patients who received 0, 50, 75, 100, and 125 ug of prophylactic nitroglycerin, respectively. The calculated ED₅₀ and ED₉₅ of nitroglycerin for preventing hypertension were 54 μg (95%CI: 35~66 μg) and 136 μg (95%CI: 105~289 μg).

Conclusion

A prophylactic bolus of nitroglycerin administered immediately following injection of pituitrin into the myometrium during laparoscopic myomectomy effectively prevented pituitrin-induced hypertension, with the ED₅₀ and ED₉₅ of 54 μg and 136 μg, respectively. This information would be useful for clinical practice.

Clinical trial registration

www.chictr.org.cn, Identifier ChiCTR2200062282.

The human NTG model of migraine in drug discovery and development

INTRODUCTION

Various triggers can originate a migraine attack. In healthy volunteers and patients with migraine, the nitroglycerin (NTG) provocation model induces a headache that resembles migraine in pain characteristics and vascular manifestations. This headache is reversible and treatable in monitored conditions, providing an opportunity to test novel antimigraine medications in early clinical development.

AREAS COVERED

This perspective covers the main characteristics and applications of the human NTG model of migraine with effective and ineffective antimigraine therapies.

EXPERT OPINION

The NTG model represents a potential de-risking strategy to test novel hypotheses for antimigraine mechanisms in humans. Considering previous studies conducted with effective and ineffective antimigraine therapies, the sensitivity of the model was 71% while the specificity was 100%. The probability that following an analgesic effect, that compound would truly be efficacious in individuals with migraine was 100%. Following a negative result, the probability that such compound would truly be ineffective in patients with individuals was 33%. A clinical trial testing the analgesic properties of novel compounds after a sublingual and/or intravenous NTG challenge in migraine patients may support a subsequent phase 2 trial for the treatment of migraine.

Nitroglycerin Ointment on the Incidence of Chemotherapy-Induced Phlebitis: A Single Blind Clinical Trial

BACKGROUND

Phlebitis is a severe inflammatory response in patients undergoing chemotherapy that can lead to complications and increased length of hospitalization.

OBJECTIVE

This study was conducted to examine the effects of sesame oil and nitroglycerin ointment on the incidence of chemotherapy-induced phlebitis in patients with cancer.  Methods: This clinical trial study involved 138 cancer patients who were randomly assigned into three groups. The three groups received nitroglycerin ointment, sesame oil, or betadine alcoholic solution that were applied on the distal catheter area at a length of 1.5 centimeters and width of 2 × 4 cm using graded paper. The site was then dressed and fixed with anti-allergenic adhesives. The research samples were examined for 72 hours for the incidence of phlebitis.

RESULTS

No statistically significant difference was observed between the incidence of phlebitis in the sesame oil, nitroglycerin ointment and alcohol-betadine groups in the first 24 hours (p=0.2), the second 24 hours (p=0.13) and the third 24 hours (p=0.13).

CONCLUSION

External use of both sesame oil and nitroglycerin is effective in reducing chemotherapy-induced phlebitis. Due to its anti-inflammatory effect and low cost, however, using sesame oil is recommended.

A comparative study between angiotensin receptor neprilysin inhibitor (thiorphan/irbesartan) with each of nitrate and carvedilol in a rat model of myocardial ischemic reperfusion injury

The combined angiotensin receptor neprilysin inhibitor is a promising cardioprotective pharmacological agent. This study investigated the beneficial effects of thiorphan (TH)/irbesartan (IRB), in myocardial ischemia-reperfusion (IR) injury, compared to each of nitroglycerin and carvedilol. Male Wistar rats were divided into five groups (10 rats/group): Sham, untreated I/R, TH/IRB + IR (0.1/10 mg/kg), nitroglycerin + IR (0.2 mg/kg), and carvedilol + IR (10 mg/kg). Mean arterial blood pressure, cardiac functions and arrhythmia incidence, duration and score were assessed. Cardiac levels of creatine kinase-MB (CK-MB), oxidative stress, endothelin-1, ATP, Na⁺ /K⁺ ATPase pump activity and mitochondria complexes activities were measured. Histopathological examination, Bcl/Bax immunohistochemistry studies and electron microscopy examination of left ventricle were performed. TH/IRB preserved the cardiac functions and mitochondrial complexes activities, mitigated cardiac damage, reduced oxidative stress and arrhythmia severity, improved the histopathological changes and decreased cardiac apoptosis. TH/IRB showed a comparable effect to each of nitroglycerin and carvedilol in alleviating the IR injury consequences. TH/IRB showed significant preservation of mitochondrial complexes activity I and II compared to nitroglycerin. TH/IRB significantly increased LVdP/dtmax and decreased oxidative stress, cardiac damage and endothelin-1 along with increasing the ATP content, Na⁺ /K⁺ ATPase pump activity and mitochondrial complexes activity when compared to carvedilol. TH/IRB showed a cardioprotective effect in reducing IR injury that is comparable to each of nitroglycerin and carvedilol that could be explained in part by its ability to preserve mitochondrial function, increase ATP, decrease oxidative stress as well as endothelin 1.

Can Significant Coronary Artery Disease Coexist With Transient Takotsubo Cardiomyopathy, and How Does Spasm Interrelate?

An 86-year-old woman being treated for metastatic breast cancer developed severe chest pain at rest during a follow-up visit at a hospital's outpatient oncology clinic. An electrocardiogram showed severe ST-segment elevation. The patient was given sublingual nitroglycerin and was transferred to the emergency department. Diagnostic coronary angiography revealed moderate coronary artery disease with calcific stenoses and transient spastic occlusion of the left anterior descending coronary artery. For this patient, sublingual nitroglycerin aborted the spastic event and apparent transient takotsubo cardiomyopathy. Chemotherapy can potentially cause endothelial dysfunction and increased coronary spasticity, which could result in takotsubo cardiomyopathy.

Effect of randomized prophylactic nitroglycerin on radial artery spasm during transradial catheterization: An analysis based on operator experience

One limitation to transradial access (TRA) is the occurrence of spasms (RAS), for which the use of prophylactic medications is recommended. Improvement in TRA material combined with the increase in operators' expertise, might mitigate this benefit. We assess the effect of preventive nitroglycerin on RAS during TRA, evaluating the role of the operator's experience. Patients received 500 μg nitroglycerin or placebo. The operator's expertise was classified as: inexperienced (I), intermediate (M), and experienced (E). 2040 patients were included. Prophylactic use of nitroglycerin did not reduce RAS (10.8% vs. 13.4% (placebo), p = 0.07). RAS incidence was 14.5% in I, 12.5% in M, and 9.7% in E (p = 0.01). In group I, nitroglycerin reduced RAS (17.4% vs. 11.1%, p = 0.04), which was not observed in other groups. Overall, nitroglycerin does not prevent RAS, which is more common among inexperienced operators. More experienced operators could abolish preventive nitroglycerin use.

Postreperfusion Syndrome Presenting as Posttransplant Portal Hypertension due to Prolonged Elevation of Pulmonary Vascular Resistance and the Role of Nitroglycerin in Diagnosis and Treatment: A Case Report of Budd-Chiari Syndrome

Postreperfusion syndrome is one of the responsible mechanisms of portal hypertension in patients undergoing liver transplantation. And post-transplant portal hypertension causes graft dysfunction. Postreperfusion syndrome is characterized by a decrease in arterial pressure and cardiac output, and an increase in central venous pressure, pulmonary artery pressure, and pulmonary vascular resistance that occurs after the release of the portal vein clamp. Although early recovery from postreperfusion syndrome is desired, there is a little medication therapy such as the administration of calcium chloride, sodium bicarbonate, and beta-agonist for postreperfusion syndrome. We present a case of postreperfusion syndrome manifested as post-transplant portal hypertension and reversed after nitroglycerin administration. A 49-year-old Asian woman was scheduled for liver transplantation because of Budd-Chiari syndrome. After portal vein reperfusion, she experienced severe postreperfusion syndrome. Administration of ephedrine and calcium restored arterial pressure; however, pulmonary artery pressure, pulmonary vascular resistance, and central venous pressure elevations were sustained, causing right ventricular overload. This condition did not improve after hepatic artery reperfusion, and caused post-transplant portal hypertension. After nitroglycerin administration, pulmonary vascular resistance and central venous pressure decreased, mean arterial pressure increased, right heart contractility recovered, and portal hypertension disappeared. Hemodynamic improvement by nitroglycerin administration helped in diagnosing postreperfusion syndrome and avoiding unnecessary splenectomy. If portal vein pressure increases after liver transplantation, the change in hemodynamic parameters by nitroglycerin administration should be assessed, which will lead to accurate diagnosis and appropriate treatment. Furthermore, postreperfusion syndrome should be listed as a differential diagnosis of post-transplant portal hypertension.

Acute sleep deprivation aggravates nitroglycerin-evoked hyperalgesia in mice

Sleep deprivation can trigger migraine, and migraineurs often choose to sleep to relieve headaches during acute migraine. This study aimed to explore the effect of acute sleep deprivation on hyperalgesia induced by nitroglycerin in mice. In part one, after either 6-h sleep deprivation or 6-h normal sleep, mice were intraperitoneally injected with nitroglycerin or saline. The mechanical pain threshold and withdrawal latency of the hindpaw were measured every 30 min for 6 h. Next, the same sleep deprivation and injection procedure was performed with new mice, and mice were sacrificed 4.5 h after injection. The trigeminal nucleus caudalis and upper cervical spinal segments were taken for immunofluorescence Fos staining. In part two, after injection of saline or nitroglycerin, the mice were either deprived of sleep for 6 h or allowed to sleep without interference. The mechanical and thermal pain threshold were measured after 6 h. In part three, we compared the sleep time of mice after intraperitoneal injection of saline or nitroglycerin without interference. Sleep deprivation for 6 h did not cause any changes in the baseline pain thresholds in mice. However, pretreatment with 6-h sleep deprivation significantly prolonged the duration of hyperalgesia induced by nitroglycerin. Additionally, the expression of Fos at 4.5 h was significantly higher in the 6-h sleep deprivation and nitroglycerin group than in the other three groups. When intraperitoneal injection was given first, the mechanical pain threshold of the hind paw was significantly lower in the group that received nitroglycerin with 6-h sleep deprivation than in the other groups. Compared to the saline injection, one-time nitroglycerin injection would result in a significant increase in sleep latency and decrease in sleep duration for the normal mice. Acute sleep deprivation significantly aggravated the hyperalgesia induced by nitroglycerin in mice, which highlights the importance of sleep disorders for migraine.

Comparison of the effects of tranexamic acid, nitroglycerin, and remifentanil on the prevention of bleeding during herniated lumbar intervertebral disc surgery: A randomized clinical trial

Background

Surgery is a well-known and effective method of treating lumbar intervertebral disc herniation. The present study aimed to compare the effects of administering tranexamic acid (TXA), nitroglycerin (NTG), and remifentanil (REF) on hemorrhage prevention during herniated lumbar intervertebral disc surgery.

Methods

A double-blind clinical trial was conducted on 135 participants undergoing lumbar intervertebral disc surgery. A randomized block design was used for subject assignment to three groups including TXA, NTG, and REF. The hemodynamic parameters, bleeding rate, hemoglobin level, and the amount of infused propofol were measured and recorded after surgery. Data were then analyzed in SPSS software using Chi-square test and analysis of variance.

Results

The mean age of participants in the study was 42.12 ± 7.93 years, and all three groups were equal in terms of demographic characteristics (P > 0.05). The mean arterial pressure (MAP) of the TXA and NTG groups was notably higher than the REF group (P < 0.008). The mean heart rate (HR) of the TXA and NTG groups was notably higher than the REF group (P < 0.05). The propofol dosage used in the TXA group was higher than the two groups of NTG and REF (P < 0.001).

Conclusion

Among participants undergoing lumbar intervertebral disc surgery, the greatest MAP variability was observed in the NTG group. Higher mean HR and propofol consumption was observed in the NTG and TXA groups when compared to REF. No statistically significant differences were noted between groups in oxygen saturation or bleeding risk. Based on these findings, REF may be considered a preferred surgical adjunct over TXA and NTG during lumbar intervertebral disc surgery.

The plasma fibrinogen levels in the nitroglycerin-induced chronic migraine rat model and its association between migraine-associated vestibular dysfunction

The purpose of this study was to measure the vestibular function and plasma fibrinogen level in the nitroglycerin (NTG)-induced chronic migraine rats, and explore the effect of defibrinogenation on migraine and associated vestibular dysfunction. The chronic migraine rat model was built by recurrent NTG injection. Batroxobin was administrated as a defibrinogenating drug. We measured the mechanical withdrawal threshold, vestibular function, and fibrinogen level of the rats 30 min before and 2 h following the model establishment, as well as 1 h after batroxobin administration. The results showed that vestibular function was impaired in NTG-induced chronic migraine rats. The fibrinogen levels were increased following repeated NTG injections. However, defibrinogenation did not affect either aggravating or alleviating mechanical hyperalgesia or vestibular dysfunction in the migraine model rats. These findings suggest that the NTG-induced chronic migraine rat model can be used for research on migraine-associated vestibular symptoms. Albeit the association between elevated fibrinogen levels and migraine attacks can be observed, the role of excessive fibrinogen in the pathogenesis of chronic migraine is yet to be determined.

Effect of transradial catheterization and nifedipine on flow- and nitroglycerin-mediated dilations of distal and proximal radial artery

OBJECTIVE

Radial artery (RA) dysfunction after transradial access intervention is not limited to the distal portion but can also occur in the proximal portion of RA. The aim of the present study was to assess the effect of sublingual nifedipine administrated prior to puncture on the endothelial function of distal and proximal RA.

METHODS

Eighty-nine patients who underwent coronary angiography (CAG) were randomly assigned to the nifedipine group ( n = 45) or control group ( n = 44). The flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD) of distal and proximal RA were measured at baseline, 24 h, and 48 h after transradial angiography.

RESULTS

Compared with the control group, the nifedipine group only limited the reduction of FMD in the distal RA at 24 and 48 h [6.52 ± 1.40% (24 h) vs. 5.85 ± 1.38% (24 h), P = 0.03; 7.41 ± 1.30% (48 h) vs. 6.65 ± 1.25% (48 h), P = 0.006], whereas FMD alterations in the proximal RA were not restored by nifedipine. Both groups were still lower than baseline values (11.66 ± 2.35% and 11.24 ± 2.22%). We observed similar effects of nifedipine on the NMD of the distal RA.

CONCLUSION

Although transradial angiography-induced dysfunction was reported in both distal and proximal RA, nifedipine could help restore the distal endothelial function of the cannulated RA.

Transient receptor potential melastatin 8 is required for nitroglycerin- and calcitonin gene-related peptide-induced migraine-like pain behaviors in mice

ABSTRACT

Migraine is a complex neurovascular disorder that is one of the leading causes of disability and a reduced quality of life. Even with such a high societal impact, our understanding of the cellular and molecular mechanisms that contribute to migraine headaches is limited. To address this complex disorder, several groups have performed genome-wide association studies to elucidate migraine susceptibility genes, with many identifying transient receptor potential melastatin 8 (TRPM8), a cold-sensitive cation channel expressed in peripheral afferents innervating the trigeminovascular system, and the principal mediator of cold and cold pain associated with injury and disease. Interestingly, these migraine-associated single-nucleotide polymorphisms reside in noncoding regions of TRPM8, with those correlated with reduced migraine risk exhibiting lower TRPM8 expression and decreased cold sensitivity. Nonetheless, as a role for TRPM8 in migraine has yet to be defined, we sought to address this gap in our knowledge using mouse genetics and TRPM8 antagonism to determine whether TRPM8 channels or neurons are required for migraine-like pain (mechanical allodynia and facial grimace) in inducible migraine models. Our results show that both evoked and spontaneous pain behaviors are dependent on both TRPM8 channels and neurons, as well as required in both acute and chronic migraine models. Moreover, inhibition of TRPM8 channels prevented acute but not established chronic migraine-like pain. These results are consistent with its association with migraine in genetic analyses and establish that TRPM8 channels are a component of the underlying mechanisms of migraine.

Valvular Heart Disease Presenting as Sympathetic Crashing Acute Pulmonary Edema (SCAPE) Phenomenon: A Diagnostic and Management Paradigm

Sympathetic crashing acute pulmonary edema (SCAPE) is an acute decompensated heart failure due to sympathetic overflow. SCAPE is usually triggered by acute insults with an underlying substrate such as long-standing hypertension, chronic heart failure, and valvular heart disease. We present a case of SCAPE in a 91-year-old female due to underlying multivalvular heart disease. Because of severe acute presentation, SCAPE should be identified early, and management should be urgently done to decrease the need for invasive ventilation and prolonged hospitalization.

The efficacy of nitroglycerin to prevent radial artery spasm and occlusion during and after transradial catheterization: A systematic review and meta-analysis of randomized controlled trials

Radial artery spasm (RAS) is the most common cause of transradial access site crossover and is a common intra-procedural complication. RAS incidence can lead to radial artery occlusion (RAO) postprocedure, preventing the radial artery as a future access site. We evaluated the efficacy of nitroglycerin preventing RAS and RAO during transradial catheterization discussing the different routes of administration, including topical, subcutaneous, and intra-arterial. A systematic review and meta-analysis included all relevant articles until April 23, 2022. We searched six databases Google Scholar, Web of Science, SCOPUS, EMBASE, PubMed (MEDLINE), and CENTRAL. We registered our review protocol in PROSPERO with ID: CRD42022330356. We included 11 trials with 5814 patients. Compared to placebo, the pooled analysis favored subcutaneous nitroglycerin in preventing RAS (risk ratio [RR]: 0.57 with 95% confidence interval [CI] [0.43-0.77], p = .0003) and RAO (RR: 0.39 with 95% CI [0.16-0.98], p = .05). In contrast to the intra-arterial nitroglycerin that showed nonstatistically significant results in preventing RAS and RAO (RR: 0.8 with 95% CI [0.63-1.02], p = .07)- (RR: 0.78 with 95% CI [0.6-1.01], p = .06)), respectively. Also, topical nitroglycerin did not prevent RAS (RR: 0.73 with 95% CI [0.42-1.24], p = .24). Compared with placebo, subcutaneous nitroglycerin during transradial catheterization reduced the incidence of RAS and RAO. Meanwhile, Intra-arterial and topical nitroglycerin did not show statistically significant outcomes. Subcutaneous nitroglycerin may be a practical and cost-effective technique to facilitate transradial catheterization; however, more RCTs are needed to evaluate the subcutaneous versus intra-arterial nitroglycerin administration.

Synthesis and Vasorelaxant Activity of Nitrate-Coumarin Derivatives

Due to the need for new chemical entities for cardiovascular diseases, we have synthesized a new series of nitrate-coumarins and evaluated their vasorelaxant activity in contraction-relaxation studies using rat aorta rings precontracted with phenylephrine or by depolarization with a high concentration of potassium chloride. Four of the new compounds were able to relax smooth vascular muscle with a similar profile and potency to glyceryl trinitrate (IC50 =12.73 nM) and sodium nitroprusside (IC50 =4.32 nM). Coumarin-7-yl-methyl nitrate (4), the best compound within the series, was able to relax smooth vascular muscle in the low nanomolar range (IC50 =1.92 nM). The mechanisms of action have been explored, being the activation of sGC and the opening of K+ channels involved. Our studies indicate that the new nitrate derivatives are reversible and not deleterious for aortic rings, suggesting that these compounds have a potential interest for the development of new and highly efficient vasodilator drugs.

Modelling migraine-related features in the nitroglycerin animal model: trigeminal hyperalgesia is associated with affective status and motor behavior

Migraine is a complex neurovascular disorder characterized by recurrent attacks of pain and other associated symptoms. Emotional-affective aspects are important components of pain, but so far they have been little explored in animal models of migraine. In this study, we aimed to explore the correlation between trigeminal hyperalgesia and affective status or behavioral components in a migraine-specific animal model. Male Sprague-Dawley rats were treated with nitroglycerin (10 mg/kg, i.p.) or its vehicle. Four hours later, anxiety, motor/exploratory behavior and grooming (a nociception index) were evaluated with the open field test. Rats were then exposed to formalin in the orofacial region to evaluate trigeminal hyperalgesia. The data analysis shows an inverse correlation between trigeminal hyperalgesia and motor or exploratory behavior, and a positive association with anxiety-like behavior or self-grooming. These findings further expand on the translational value of the migraine-specific model based on nitroglycerin administration and prompt additional parameters that can be investigated to explore migraine disease in its complexity.

Nitroglycerin Use in the Emergency Department: Current Perspectives

Nitroglycerin, a fast-acting vasodilator, is commonly used as a first-line agent for angina in the emergency department and to manage chest pain due to acute coronary syndromes. It is also a treatment option for other disease states such as acute heart failure, pulmonary edema, and aortic dissection. Nitroglycerin is converted to nitric oxide, a potent vasodilator, in the body, leading to venodilation at lower dosages and arteriodilation at higher dosages that results in both preload and afterload reduction, respectively. Although nitroglycerin has historically been administered as a sublingual tablet and/or spray, it is often given intravenously in the emergency department as this enables titration to effect with predictable pharmacokinetics. In this review article, we outline the indications, mechanism of action, contraindications, and adverse effects of nitroglycerin as well as review relevant literature and make general recommendations regarding the use of nitroglycerin in the emergency department.

PROPHYLACTIC EFFECT OF NITRIC OXIDE DONORS ON RAT MODELS OF EGFR INHIBITORS-INDUCED CUTANEOUS TOXICITIES

Epidermal growth factor receptor inhibitors (EGFRIs) have been established as first-line standard-of-care therapies for non-small cell lung cancer (NSCLC) but are frequently accompanied by adverse dermatological effects, in particular, acneiform rash. There is no effective clinical intervention, partially because of its poorly understood etiology. Here, we show that inhibition of EGFR initiated keratinocyte HaCaT cell cycle arrest and apoptosis, which fueled a robust secondary inflammatory response. Rats gavaged with EGFRI showed a phenotype similar to that of clinical patients, which was in line with the interrupted functions observed in HaCaT keratinocytes. We found that a nitric oxide (NO) donor, nitroglycerin (GTN), was a feasible treatment alternative for EGFRI-induced rash. Restoration of epidermal extracellular signal-regulated kinase (ERK) and a reduction in STAT3 signaling via GTN treatment rescued the cellular functions that had been damaged in vitro and further ameliorated the rash in rat models. In addition, the efficacy of GTN was superior to that of existing clinical interventions. These data highlighted the importance of epidermal EGFR signaling and led to the identification of a small-molecule NO donor as a mediator that can maintain EGFR pathway functions during anti-EGFR therapies, providing a therapeutic anchor point for adverse EGFRI-induced skin effects.

Randomized Clinical Trial on Prevention of Radial Occlusion After Transradial Access Using Nitroglycerin: PATENS Trial

OBJECTIVES

The aim of this study was to evaluate whether administration of nitroglycerin at the beginning or end of a transradial approach (TRA) procedure would preserve radial patency.

BACKGROUND

The TRA is becoming the preferred vascular access route in coronary interventions. Radial artery occlusion (RAO) is the most frequent complication. Routine vasodilator treatment aims to reduce spasm and possibly prevent RAO.

METHODS

The authors designed a prospective, multicenter, randomized, double-blind, 2-by-2 factorial, placebo-controlled trial encompassing patients undergoing the TRA. Patients were randomized to either 500 μg nitroglycerin or placebo; each arm was also subrandomized to early (upon sheath insertion) or late (right before sheath removal) nitroglycerin administration to evaluate the superiority of nitroglycerin in the prevention of RAO with 24 hours on Doppler ultrasound.

RESULTS

A total of 2,040 patients were enrolled. RAO occurred in 49 patients (2.4%). Fifteen of these patients (30.6%) showed re-establishment of flow at 30 days. Nitroglycerin, compared with placebo, did not reduce the risk for RAO at either of the 2 time points (early, 2.5% vs 2.3% [P = 0.66]; late, 2.3% vs 2.5% [P = 0.66]). By multivariable analysis, the presence of spasm (OR: 3.53; 95% CI: 1.87-6.65; P < 0.001) and access achieved with more than 1 puncture attempt (OR: 2.58; 95% CI: 1.43-4.66; P = 0.002) were independent predictors of RAO.

CONCLUSIONS

The routine use of nitroglycerin was not associated with a reduction in the rate of RAO, regardless of the time of administration (at the beginning or end of the TRA procedure).

Acute tocolysis for intrapartum nonreassuring fetal status: how often does it prevent cesarean delivery? A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This study aimed to evaluate the effectiveness of intrapartum acute tocolysis for nonreassuring fetal heart rate tracing in decreasing the incidence of cesarean delivery. Secondary outcomes included modes of delivery other than cesarean delivery, successful acute tocolysis, time-to-delivery interval, and short-term perinatal outcomes.

DATA SOURCES

Searches were performed in MEDLINE/PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials and Reviews, ClinicalTrials.gov, and the International Clinical Trials Registry Platform from the inception of each database until February 2022.

STUDY ELIGIBILITY CRITERIA

Selection criteria included randomized controlled trials of laboring patients with singleton gestations randomized to receive intrapartum acute tocolysis for nonreassuring fetal heart rate tracing, as defined by the original trial.

METHODS

All analyses were done using an intention-to-treat approach, evaluating women according to the treatment group to which they were randomly allocated in the original trials. A frequentist network-meta-analysis was performed.

RESULTS

Four randomized clinical trials were eligible, including 605 patients with nonreassuring fetal heart rate tracing and singleton gestations at gestational ages >32 weeks. The cesarean delivery rate was similar among patients managed with different types of acute tocolysis. Acute tocolysis, compared with emergency delivery, was associated with improved neonatal acid-base status (notably decreasing the prevalence of base deficit >12 mmol/L [beta-2 agonists odds ratio, 0.61; 95% confidence interval, 0.37-0.99] and the rate of neonatal intensive care unit admission [beta-2 agonists odds ratio, 0.42; 95% confidence interval, 0.22-0.78]) and with an increase in the time-to-delivery interval (beta-2 agonists mean difference, 17.62 minutes; 95% confidence interval, 15.66-19.58); there was no reduction of cesarean delivery rate, showing an increased rate with atosiban and beta-2 agonists.

CONCLUSION

The cesarean delivery rate was not reduced by acute tocolysis when used for nonreassuring fetal heart rate tracing during labor. Acute tocolysis is associated with improved short-term fetal outcomes and safely increases the time-to-delivery interval.

Cerebral Oximetry-Monitored Nitroglycerin Infusion and Tissue Perfusion during Rewarming of Cardiopulmonary Bypass in Cardiac Surgery: A Prospective Randomized Trial

Background: Nitroglycerin facilitates microcirculation and oxygen delivery through vasodilation. The purpose of this study was to clarify the effects of nitroglycerin-induced vasodilation and potential hypotension on tissue perfusion under cerebral oximetry monitoring during rewarming in cardiopulmonary bypass. Methods: Elective cardiac surgical patients were randomly assigned to either a nitroglycerin group (n = 32) with an intravenous infusion of 1–5 mcg/kg/min or a control group (n = 31) with 0–0.1 mcg/kg/min infusion, since the initiation of rewarming. Perioperative arterial blood gas data were collected in addition to hemodynamic variables, cerebral oximetry values, urine output, and postoperative outcomes. Results: Nearly one-fifth (6/32) of patients in the nitroglycerin group experienced transient (≤5 min) profound hypotension (mean arterial blood pressure ≤40 mmHg) after the initiation of infusion. There were no significant differences between groups in terms of perioperative levels of cerebral oximetry, cardiac index, plasma glucose, lactate, bicarbonate, base excess, or post-bypass activated coagulation time. In the nitroglycerin group, urine output was nonsignificantly higher during cardiopulmonary bypass (p = 0.099) and within 8 h after surgery (p = 0.157). Perioperative transfused blood products, postoperative inotropic doses, extubation time, and intensive care unit stay were comparable for the two groups. Conclusions: Initiation of intravenous nitroglycerin infusion (at 1–5 mcg/kg/min) during rewarming in hypothermic cardiopulmonary bypass resulted in transient profound hypotension in one-fifth of patients and did not improve perioperative cerebral oxygenation, tissue perfusion, and coagulation in cardiac surgery.

Nicardipine versus nitroglycerin for hypertensive acute heart failure syndrome: a single-center observational study

Objective: Nitroglycerin is a first-line treatment for hypertensive acute heart failure syndrome (AHFS). However, nicardipine is frequently used to treat hypertensive emergencies, including AHFS. In this study, we compared the effectiveness of nicardipine and nitroglycerin in patients with hypertensive AHFS.

Patients and Methods: This single-center, retrospective, observational study was conducted at the intensive care unit of a Japanese hospital. Patients diagnosed with AHFS and systolic blood pressure 140 mmHg on arrival between April 2013 and March 2021 were included. The outcomes were the time to optimal blood pressure control, duration of continuous infusion of antihypertensive agents, duration of positive pressure ventilation, need for additional antihypertensive agents, length of hospital stay, and body weight changes. Outcomes were compared between the nicardipine and nitroglycerin groups. We also compared these outcomes between the groups after excluding patients who received renal replacement therapy.

Results: Fifty-eight patients were enrolled (26 and 32 patients were treated with nitroglycerin and nicardipine, respectively). The nicardipine group had a shorter time to optimal blood pressure control (2.0 [interquartile range, 2.0–8.5] h vs. 1.0 [0.5–2.0] h), shorter duration of continuous anti-hypertensive agent infusion (3.0 [2.0–5.0] days vs. 2.0 [1.0–2.0] days), less frequent need for additional anti-hypertensive agents (1 patients [3.1%] vs. 11 patients [42.3%]), and shorter length of hospital stay (17.5 [10.0–33.0] days vs. 9.0 [5.0–15.0] days) than the nitroglycerin group. The duration of positive pressure ventilation and body weight changes were similar between the groups. The outcomes were similar after excluding patients who received renal replacement therapy.

Conclusion: Nicardipine may be more effective than nitroglycerin for treating hypertensive AHFS.

Acetylcholine Rechallenge: A First Step Toward Tailored Treatment in Patients With Coronary Artery Spasm

OBJECTIVES

The present study aimed to assess the feasibility and clinical value of acetylcholine (ACh) rechallenge for the detection of coexisting epicardial and microvascular spasm and to determine the efficacy of nitroglycerin in these spasm endotypes.

BACKGROUND

The coexistence of epicardial and microvascular spasm is difficult to identify; thus, its frequency is unknown. Nitroglycerin treatment is equally recommended for both epicardial and microvascular coronary spasm despite contradictory data.

METHODS

In this multicenter study, 95 patients with coronary spasm were included to undergo ACh rechallenge, which consisted of repeated ACh provocation 3 minutes after intracoronary nitroglycerin administration using the same dose that previously induced spasm.

RESULTS

In total, 95 patients (age 61 ± 12 years, 69% female) were included. Fifty-five patients (58%) had microvascular spasm, and 40 patients (42%) had epicardial spasm during initial ACh provocation. In 48% of patients with epicardial spasm, ACh rechallenge revealed coexisting nitroglycerin-persistent microvascular spasm. Nitroglycerin administration before ACh rechallenge prevented reinducibility of epicardial spasm in all patients with focal spasm and in 80% of patients with diffuse spasm. Microvascular spasm was prevented in only 20% by prior nitroglycerin administration but was attenuated in another 49% of patients.

CONCLUSIONS

This study demonstrates a high frequency of epicardial spasm with coexisting nitroglycerin-persistent microvascular spasm. Intracoronary nitroglycerin was very effective in preventing reinducibility of epicardial spasm, whereas it prevented microvascular spasm in only 20% of patients. ACh rechallenge is a novel method that facilitates the detection of coexisting spasm endotypes and may pave the way towards tailored treatment of vasospastic angina.

Primary erythromelalgia mainly manifested by hypertensive crisis: A case report and literature review

BACKGROUND

Primary erythrocytic (PEM) is a rare autosomal dominant single gene disease. Most of the changes of gene loci can be found by whole exon gene sequencing, and the clinical symptoms and patient survival can be improved by specific site-to-site drug treatment. The other manifestations of this patient population are not remarkable. After the application of common drugs, the toxicity and side effects can be limiting. In addition to other common clinical manifestations, we found that the only unique manifestation of this patient was hypertensive crisis. Following multidisciplinary diagnosis and treatment (MDT), we decided to first control hypertension to alleviate the acute and critical patients. However, after controlling the hypertensive crisis, we unexpectedly found that the clinical symptoms of the patients had been significantly improved. Therefore, we concluded that the use of antihypertensive drugs can treat erythematous limb pain with the clinical manifestation of hypertensive crisis. Here, we describe a typical PEM disease, primary clinical features, diagnosis and treatment.

METHODS

Medical records of an 8-year-old boy with PEM were analyzed retrospectively, which included clinical characteristics, follow-up information, and SCN9A (Sodium Voltage-Gated Channel Alpha Subunit 9) gene analysis.

RESULTS

The 8-year-old boy had complained of abnormal paresthesia in his feet and ankles with burning sensation and pain for 2 years. The skin of both lower legs was red and underwent ichthyosis and lichenification. Genetic analysis confirmed the existence of a SCN9A gene mutation. The symptoms were gradually improved by treating with intravenous drip and oral administration of nitroglycerin to slow his heart rhythm.

CONCLUSION

Primary erythrocytic is characterized by skin ulceration, redness, elevated temperature, and severe burning pain primarily in both lower extremities. PEM can be diagnosed by genetic analysis. As this case demonstrates, treating with nitroglycerin as the drug of choice to control the hypertensive crisis significantly improved the symptoms of PEM and hypertension in this patient.

Nitroglycerin as a Treatment Modality for Recurrent Isolated Paracentral Acute Middle Maculopathy: A Case Report

Paracentral acute middle maculopathy (PAMM) is a condition characterized by ischemia affecting the deep capillary plexus layer of the macula, often resulting in a paracentral visual scotoma. PAMM has been reported in association with retinal vascular diseases or as an isolated phenomenon in young and healthy individuals. There is currently no treatment for PAMM. We report a case in which sublingual nitroglycerin reversed developing visual scotomas, or blind spots, in a patient with known recurrent episodes of PAMM. 

This case describes a male patient with previously documented evidence of PAMM in both eyes following episodes of extreme physical activity or dehydration. These episodes would often last days without ultimate resolution. After one such occurrence in his right eye, the patient was treated with a sublingual nitroglycerin tablet immediately after the development of new visual scotomas. 

The patient’s visual symptoms improved within minutes of administering sublingual nitroglycerin, and completely resolved within hours.

Study on the Chemical Constituents and Anti-Migraine Activity of Supercritical CO2 Extracts of Zanthoxylum schinifolium

Background:Zanthoxylum schinifolium is a common herbal medicine in Southwest China. It is also a condiment commonly used in many families. In Chinese folk medicine, Z. schinifolium is considered to have the effect of relieving migraine, but there is no modern evidence on its anti-migraine mechanism.

Objective: The aim of this study was to investigate the chemical constituents of the supercritical carbon dioxide extracts of Z. schinifolium (CO₂-ZSE) and its effects on migraine animals.

Materials and Methods: Supercritical CO₂ extraction technology was applied to extract the dried fruit of Z. schinifolium, and the chemical components were determined by gas chromatography–mass spectrometry (GC-MS). Two migraine animal models were established by subcutaneous injection of nitroglycerin (NTG) and reserpine, respectively, to further evaluate the therapeutic effect of CO₂-ZSE and explore its mechanism. On the basis of the experimental results, the therapeutic effects of linalool in different dosages and different ways of administration on NTG-induced migraine rats have been further investigated.

Results: About 125 peaks were detected in CO₂-ZSE, and the relative content of linalool was 74.16%. CO₂-ZSE decreased the number of head-scratching significantly and the levels of serum nitric oxide (NO), endothelin-1 (ET-1), calcitonin gene–related peptide (CGRP), interleukin-1β (IL-1β), nuclear factor kappa B (NF-κB) p65, and inhibitor of kappa B alpha (IκBα), and increased the level of 5-hydroxytryptamine (5-HT). Linalool has the potential to reduce the frequency of scratching the head and the expressions of NO, ET-1, and CGRP in NTG-induced migraine rats.

Conclusion: CO₂-ZSE has a definite therapeutic effect on migraine by affecting the expression of vasomotor factors and the inflammatory pathway. Linalool has been proven to be the main effective substance against migraine. These findings provide scientific basis for the development of effective and simple migraine therapy.

Comparative analgesic, hemodynamic, pain and duration of sensory and motor block effects of dexmedetomidine, granisetron, and nitroglycerin added to ropivacaine in intravenous anesthesia for forearm surgeries: a randomized clinical study

This trial-based paper strives to address the comparative efficacy of some ropivacaine adjuvant options, comprising dexmedetomidine, granisetron, and nitroglycerin, on pain and hemodynamic changes in intravenous anesthesia for forearm surgeries. This double-blind, placebo-controlled study enrolled four block-randomized eligible groups with patients (overall, n=128) undergoing orthopedic forearm surgeries in the dexmedetomidine, nitroglycerin, granisetron, and placebo groups. Intra- and post-operative vital signs (mean arterial pressure/heart rate/ oxygen saturation) were monitored at baseline and captured every 10 minutes until the end of the surgery, as well as the onset of sensory and motor block and length and duration of the block and mean opioid use within 24 hours. Lastly, pain was noted after tourniquet inflation (at 15, 30, and 45 minutes every 15 minutes until the end of surgery) and after deflation (every 30 minutes to 2 hours at 30, 60, 90, and 120 minutes), as well as 6, 12, and 24 hours after the tourniquet was deflated. The dexmedetomidine-sedated subjects appeared to demonstrate quicker onset and longer length and duration of sensory and motor block, plus less pain and opioid use at all scheduled times (both P = 0.0001). Dexmedetomidine is recommended as an adjuvant to regional anesthesia (Bier’s block), while being coupled with the rapid onset and prolonged length and duration of sensory and motor blocks, in addition to soothed pain and diminished opioid use within postoperative 24 hours. The study was approved by Ethics Committee of Arak University of Medical Sciences (approval No. IR.ARAKMU.REC.1398.112) on July 21, 2019, and registered at Iranian Registry of Clinical Trials (registration number IRCT20141209020258N123) on November 2, 2019.

Monitoring of Cardiorespiratory Parameters in Rats-Validation Based on Pharmacological Stimulation

The methods used in preclinical studies should minimize the suffering and the number of animals but still provide precise and consistent results enabling the introduction of drug candidates into the phase of clinical trials. Thus, we aimed to develop a method allowing us to perform preliminary safety and toxicity studies of candidates for human medicines, while reducing the number of animals. We have devised a method based on a combination of two devices: Plugsys (Transonics System Inc., Ithaca, NY, USA) and PhysioSuite (Kent Scientific Corporation, Torrington, CT, USA), which allow simultaneous registration of nine circulatory and respiratory parameters, and body temperature. Vehicle and adrenaline, or nitroglycerin, as reference substances were administered into the right femoral vein of Wistar rats. Physiological conditions were registered over 60 min after drug administration by measuring systolic, diastolic and mean blood pressure, heart rate (HR), blood perfusion of paw vessels, blood oxygen saturation, respiratory rate, average and peak exhaled CO₂, and body temperature. Blood pressure was measured by cannula placed in the left common carotid artery and connected to the pressure transducer (Plugsys). The other parameters were measured by the PhysioSuite. Adrenaline-induced immediate dose-related hypertension and nitroglycerin hypotension were correlated with the change in blood perfusion. They both increased HR. Adrenaline decreased blood oxygen saturation and slightly affected respiratory parameters, while nitroglycerin caused a progressive increase in respiratory rate and a decrease in the peak of exhaled CO₂. Our method may become an inseparable part of the preliminary safety and toxicity studies of tested drugs, while being an important step towards improving animal welfare.

The gut microbiome modulates nitroglycerin-induced migraine-related hyperalgesia in mice

BACKGROUND

Gut microbiota disturbance is increasingly suggested to be involved in the pathogenesis of migraine but this connection remains unsubstantiated. This study aimed to investigate whether the gut microbiome influences migraine-related hyperalgesia.

METHODS

Nitroglycerin-induced hyperalgesia was evaluated in mice with different gut microbiota statuses as follows: Specific pathogen-free mice; germ-free mice; specific pathogen-free mice treated with antibiotics to deplete the gut microbiome (ABX mice); and germ-free mice transplanted with the gut microbial profile from specific pathogen-free mice (GFC mice). Moreover, nitroglycerin-induced hyperalgesia was compared between recipient mice transplanted with gut microbiota from a patient with migraine and those that received gut microbiota from a sex- and age-matched healthy control.

RESULTS

In specific pathogen-free mice, a decreased mechanical threshold in the hind paw, increased grooming time, increased c-Fos expression level and decreased calcitonin gene-related peptide expression level as well as increased tumor necrosis factor-α concentration in the trigeminal nucleus caudalis were observed after nitroglycerin administration compared with saline treatment. However, increased basal sensitivity and higher basal concentrations of TNF-α in the trigeminal nucleus caudalis were observed in germ-free and ABX mice, while no significant difference in hyperalgesia was observed between the nitroglycerin group and saline group in germ-free and ABX mice. Moreover, significant hyperalgesia was induced by nitroglycerin administration in GFC mice. The mice transplanted with the gut microbial profile from a patient with migraine had more severe nitroglycerin-induced hyperalgesia than the mice receiving microbiota from a matched healthy control.

CONCLUSION

Our findings highlight the involvement of the gut microbiome in normal mechanical pain sensation and pathogenesis of migraine.

Protein kinase Cδ as a neuronal mechanism for headache in a chronic intermittent nitroglycerin model of migraine in mice

ABSTRACT

Migraine is one of the most common neurological disorders characterized by recurrent attacks of typically throbbing and unilateral headaches, affecting up to 20% of the population worldwide. Despite the high prevalence and severity of this primary headache disorder, it remains to be a challenge to fully understand and treat migraine headaches. By characterizing and validating a mouse migraine model, this study aimed to investigate the functional contribution of protein kinase C (PKC) isoforms in migraine. In this study, we identified the presence of migraine-like ongoing pain in mice after chronic intermittent treatment with nitroglycerin (NTG). The peptide antagonist of calcitonin gene-related peptide α-CGRP (8-37), but not topiramate nor sumatriptan, effectively blocked ongoing pain and elicited pain relief-induced conditioned place preference in NTG-treated mice. Prominent activation of PKCδ was observed in chronic NTG-treated mice. Functional inhibition of PKCδ significantly attenuated ongoing spontaneous pain in chronic NTG-treated mice. Furthermore, we recapitulated the NTG-triggered migraine behavior in wild-type mice, but not in PKCδ-null mice. In response to repeated administration of NTG, ongoing spontaneous pain was not developed in mice lacking the specific PKC isoform. This study identified the presence of ongoing pain in mice treated with NTG, a known human migraine trigger that closely resembles the common manifestation of spontaneous migraine attacks in humans. These findings demonstrated a critical regulatory role of PKCδ in migraine pathophysiology, which may offer new pharmacological targets for antimigraine treatment.

Exogenous Hsp70 attenuates nitroglycerin-induced migraine-like symptoms in mice

Although the connection between heat shock protein 70 (HSP70) and vestibular migraine is not clear, HSP70 is neuroprotective in other scenarios. This study aimed to investigate the potential of exogenous HSP70 for treating migraine-like symptoms in a mouse model of nitroglycerin (NTG)-induced migraine. HSP70 levels were assessed in patients with vestibular migraine and healthy individuals by ELISA. Migraine was induced in mice by NTG, and HSP70 expression was examined in the trigeminal nucleus caudalis (TNC) tissue of mice treated with NTG and NTG together with exogenous HSP70. The effects of exogenous HSP70 on migraine-like symptoms were assessed through behavioral assays. Finally, the impact of HSP70 on oxidative stress and NF-κB signaling in mice with migraine was investigated. Serum HSP70 in patients with vestibular migraine was significantly lower than that of healthy individuals. NTG administration significantly suppressed HSP70 expression in mouse TNC tissue, which was reversed by exogenous HSP70. HSP70 alleviated NTG-induced mechanical hypersensitivity, light aversion, and anxiety-like behavior. Finally, exogenous HSP70 suppressed NTG-induced oxidative stress and NF-κB signaling. Our study suggests that exogenous HSP70 may be a potential therapy for alleviating migraine symptoms and our promising finding warrants further investigation of HSP70 for clinical application.NEW & NOTEWORTHY The study suggests that exogenous HSP70 may be a potential therapy for alleviating migraine symptoms and our promising finding warrants further investigation of HSP70 for clinical application.

The Potential Synergistic Activity of Zolmitriptan Combined in New Self-Nanoemulsifying Drug Delivery Systems: ATR-FTIR Real-Time Fast Dissolution Monitoring and Pharmacodynamic Assessment

Purpose

The current work aimed to overcome the poor permeability and undesirable adverse effects of Zolmitriptan (ZMT) and to increase its efficacy in the treatment of acute migraine by exploiting the synergistic effect of the essential oil, lavender, to fabricate ZMT self-nanoemulsifying drug delivery systems (ZMT-SNEDDS).

Methods

ZMT-SNEDDS were fabricated based on full factorial design (3²) to statistically assess the impact of oil and surfactant concentrations on the nanoemulsion globule size, zeta potential and percentage drug dissolution efficiency. An ATR-FTIR method was developed and validated for continuous real-time monitoring of ZMT dissolution and permeation. The dose of the optimized ZMT-SNEDDS used in the efficacy study was selected according to the acute toxicity study. The efficacy study was performed on migraineous rats induced by nitroglycerin and was evaluated by the activity cage and thermal tests, electroencephalogram, electroconvulsive stimulation, and biochemical analysis of brain tissue. Finally, histopathological and immunohistochemical examinations of the cerebra were carried out.

Results

Upon dilution, the optimized ZMT-SNEDDS (F5) exhibited nanosized spherical droplets of 19.59±0.17 nm with narrow size distribution, zeta potential (-23.5±1.17mV) and rapid emulsification characteristics. ATR-FTIR spectra elucidated the complete time course of dissolution and permeation, confirming F5 superior performance. Moreover, ZMT-SNEDDS (F5) showed safety in an acute toxicity study. ZMT concentration in rat brain tissues derived from F5 was lower compared to that of ZMT solution, yet its effect was better on the psychological state, algesia, as well as maintaining normal brain electrical activity and delayed convulsions. It counteracted the cerebral biochemical alternations induced by nitroglycerin, which was confirmed by histopathological examination.

Conclusion

In a nutshell, these findings corroborated the remarkable synergistic efficacy and the high potency of lavender oil-based ZMT-SNEDDS in migraine management compared to the traditional zolmitriptan solution.

Spinal nociceptive sensitization and plasma palmitoylethanolamide levels during experimentally induced migraine attacks

ABSTRACT

Migraine pathophysiology has been suggested to include dysregulation of the endocannabinoid system (ES). We simultaneously evaluated plasma anandamide (AEA) and palmitoylethanolamide (PEA) levels and spinal sensitization in a validated human model of migraine based on systemic nitroglycerin (NTG) administration. Twenty-four subjects with episodic migraine (MIG) and 19 healthy controls (HC) underwent blood sampling and investigation of nociceptive withdrawal reflex thresholds (RTh: single-stimulus threshold; TST: temporal summation threshold) before and 30 (T30), 60 (T60), and 120 (T120) minutes after sublingual NTG administration (0.9 mg). At baseline, the MIG and HC groups were comparable for plasma AEA (P = 0.822) and PEA (P = 0.182) levels, and for RTh (P = 0.142) and TST values (P = 0.150). Anandamide levels increased after NTG administration (P = 0.022) in both groups, without differences between them (P = 0.779). By contrast, after NTG administration, PEA levels increased in the MIG group at T120 (P = 0.004), while remaining stable in the HC group. Nitroglycerin administration induced central sensitization in the MIG group, which was recorded as reductions in RTh (P = 0.046) at T30 and T120, and in TST (P = 0.001) at all time points. In the HC group, we observed increases in RTh (P = 0.001) and TST (P = 0.008), which suggest the occurrence of habituation. We found no significant correlations between the ES and neurophysiological parameters. Our findings suggest a role for PEA in the ictal phase of episodic migraine. The ES does not seem to be directly involved in the modulation of NTG-induced central sensitization, which suggests that the observed PEA increase and spinal sensitization are parallel, probably unrelated, phenomena.