5-Hydroxytryptamine (5-HT) or serotonin plays a crucial role as a neuromodulator and/or neurotransmitter of several nervous system functions. Its actions are complex and depend on multiple factors, including the type of effector or receptor activated. Briefly, 5-HT can activate: (i) metabotropic (G-protein-coupled) receptors to promote inhibition (5-HT1, 5-HT5) or activation (5-HT4, 5-HT6, 5 HT7) of adenylate cyclase, as well as activation (5-HT2) of phospholipase C; and (ii) ionotropic receptors (5-HT3), which form a ligand-gated Na+/K+ channel. Regarding blood pressure regulation (and beyond the intricacy of central 5-HT effects), this monoamine also exerts direct postjunctional (on vascular smooth muscle and endothelium) or indirect prejunctional (on autonomic and sensory perivascular nerves) effects. At the prejunctional level, 5-HT can facilitate or preclude the release of autonomic (e.g., noradrenaline and acetylcholine) or sensory (e.g., calcitonin gene-related peptide) neurotransmitters facilitating hypertensive or hypotensive effects. Hence, we cannot formulate a specific impact of 5-HT on blood pressure level, since an increase or decrease in neurotransmitter release would be favoured depending on the type of prejunctional receptor involved. This review summarizes and discusses the current knowledge on the prejunctional mechanisms involved in blood pressure regulation by 5-HT and its impact on some vascular-related diseases.

Background/Objectives: Research on calcitonin gene-related peptide (CGRP) in adult migraine is extensive, but its role in childhood migraine remains unclear. This study aimed to evaluate serum CGRP levels in children experiencing migraine and tension-type headache (TTH) during interictal periods, comparing these levels to age-matched healthy controls. Methods: A total of 66 migraine patients, 59 with TTH, and 53 controls were recruited and strat-ified by headache onset age: under 7, 7-12, and over 12 years. CGRP levels were quantified using enzyme-linked immunosorbent assay (ELISA). Results: Migraine patients showed significantly higher serum CGRP levels than both TTH pa-tients and controls (p < 0.001) with no significant difference between the latter two groups. Among migraine patients, those without aura (MO) exhibited higher CGRP levels than those with aura (MA). CGRP levels were lower in MA patients whose headaches began between ages 7-12 compared to subjects with MO, while no significant differences were found in patients whose headaches began after age 12. Conclusions: These findings suggest elevated serum CGRP is indicative of pediatric migraine, with variations based on migraine type and age of onset. The difference in CGRP in preadolescent migraineurs with and without aura suggest that CGRP levels may vary depending on the age and on migraine type.

Abstract Background The advent of monoclonal antibodies (mAbs) targeting calcitonin gene-related peptide (CGRP) pathway has transformed the management of migraine, offering newfound optimism for clinicians and individuals with episodic migraine (EM) and chronic migraine (CM). While randomized controlled trials (RCTs) have provided crucial insights into the effectiveness and safety profiles of these treatments, their translation into real-world clinical practice remains a e challenge. Objective This review aims to conduct a comprehensive assessment of real-world studies, offering valuable insights tailored for practical application in clinical settings. Methods We conducted a comprehensive literature search in PubMed, SCOPUS, and MEDLINE for real-life studies on erenumab, fremanezumab, and galcanezumab. Abstracts underwent rigorous screening by two reviewers for relevance. Data extraction from selected articles was performed using a standardized form, with verification by a second reviewer. Data synthesis was narrative, following PRISMA guidelines. Results Our search included 55 pertinent studies conducted between 2019 and 2023. Real-world study designs demonstrated notable variability in the selection and inclusion of migraine patients, influenced by factors such as attack frequency, data collection criteria, and primary/secondary objectives. Key findings commonly reported considerable improvements in efficacy outcomes (migraine frequency, analgesic use, pain severity, disability), high responder rates, and optimal safety and tolerability profiles. Conclusion Real-world evidence underscores the role of anti-CGRP mAbs as targeted therapies for both CM and EM patients. The overall results indicate that the effectiveness and tolerability of anti-CGRP mAbs in real-world applications may exceed those observed in RCTs, an unprecedented finding in clinical neurology.

This retrospective study assesses the efficacy and tolerability of anti-CGRP therapy in adolescents and young adults (ages 12-21) with migraines and chronic daily headaches unresponsive to standard treatments. Migraines severely affect school performance, self-esteem, psychological well-being, and cognitive health in this demographic, who are also sensitive to the side effects of conventional medications often prescribed off-label and face high insurance denial rates. Medication overuse, including analgesics, triptans, and NSAIDs, is prevalent due to treatment failures. Elevated plasma CGRP levels during migraines suggest that anti-CGRP therapies, which have shown success in adults, might benefit this age group. Over three years, patients at a specialized headache center were evaluated for the impact of anti-CGRP treatments, including monoclonal antibodies (erenumab, fremanezumab, galcanezumab) and small molecule CGRP receptor antagonists (ubrogepant, rimegepant, atogepant), either alone or in combination with OnabotulinumtoxinA. The study found significant improvements in migraine management, especially among older adolescents, with reduced rescue medication use and emergency visits. Longer treatment courses and combination therapy with traditional medications were more effective than monotherapy, reducing migraine intensity and frequency. Adverse effects were minimal, and no significant medication interactions were noted. Anti-CGRP therapy demonstrates substantial potential in improving outcomes for this age group with chronic and episodic migraines.

Objective: The study aimed to evaluate the effects of monoclonal antibodies (mAbs) acting on the calcitonin gene-related peptide (CGRP) or its receptor (anti-CGRP/R mAbs) on comorbid symptoms of depression, anxiety, and fatigue in migraine patients resistant to traditional prophylaxis. Methods: The study was an open-label prospective study assessing comorbidities in patients with high frequency (HFEM) and chronic migraine (CM), medication overuse headache (MOH), and resistance to traditional prophylaxis treated with anti-CGRP/R mAbs for 3 months. Results: 77 patients were enrolled with either HFEM (21%) or CM (79%) with or without MOH (56% and 44% respectively). We identified 21 non-responders (27%) and 56 responders (73%), defined on the reduction ≥ 50% of headache frequency. The two groups were highly homogeneous for investigated comorbidities. Disease severity in terms of headache frequency, migraine-related disability, and affective comorbid symptoms were reduced in both groups with different thresholds; allodynia and fatigue were ameliorated only in responders. Conclusion: anti-CGRP/R antibodies improve pain together with affection, fatigue, and sensory sensitization in migraine patients.

Migraine and stroke are neurological disorders with significant global prevalence and impact. Recent advances in migraine therapy have focused on calcitonin gene-related peptide (CGRP) pathway. This review examines the shared pathomechanisms between migraine and stroke, with emphasis on the role of CGRP. We analyze current literature on CGRP's functions in cerebrovascular regulation, edema formation, neuroinflammation, and neuroprotection. CGRP acts as a potent vasodilator and plays a crucial role in trigeminovascular activation during migraine attacks. In stroke, CGRP has demonstrated neuroprotective effects by improving collateral circulation and reducing ischemia-reperfusion injury. Concerns have been raised about the potential impact of CGRP inhibsitors on stroke risk and outcomes. Studies in animals suggest that CGRP receptor antagonists may worsen cerebral ischemia by impairing collateral flow. We discuss the implications of these findings for the use of CGRP-targeting therapies in migraine patients, especially those at increased risk of stroke. Additionally, we explore the complex interplay between CGRP, endothelial function, and platelet activity in both conditions. This review highlights the need for further research to elucidate the long-term cerebrovascular safety of CGRP pathway inhibitors and to identify potential subgroups of migraine patients who may be at higher risk of adverse cerebrovascular events with these novel therapies.

Migraine is a neurovascular disorder that affects approximately 12% of the global population. While its exact causes are still being studied, researchers believe that nociceptors in the trigeminal ganglia play a key role in the pain signals of migraine. These nociceptors innervate the intracranial meninges and convey pain signals from the meninges to the thalamus. Targeting these nociceptors is considered promising due to their accessibility and distinct molecular profile, which includes the expression of several transient receptor potential (TRP) channels. These channels have been linked to various pain conditions, including migraine. This review discusses the role and mechanisms of nociceptors in migraine, the challenges of current antimigraine drugs, and the evidence for well-studied and emerging TRP channels, particularly TRPC4, as novel targets for migraine prevention and treatment.

Migraine is a debilitating neurological condition affecting millions of people worldwide. Until few years ago, preventive migraine treatments were based on molecules with pleiotropic targets, developed for other indications and discovered by serendipity to be effective in migraine prevention although often burdened by tolerability issues leading to low adherence. However, the progresses in unravelling the migraine pathophysiology allowed to identify novel putative targets as calcitonin gene-related peptide (CGRP). Nevertheless, despite the revolution brought by CGRP monoclonal antibodies and gepants, a significant percentage of patients still remains burdened by an unsatisfactory response suggesting that other pathways may play a critical role with an extent of involvement varying among different migraine patients. Specifically, neuropeptides of the CGRP family as adrenomedullin and amylin, molecules of the secretin family as pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP), receptors as transient receptor potential (TRP) channels, intracellular downstream determinants as potassium channels but also the opioid system and the purinergic pathway have been suggested to be involved in migraine pathophysiology. The present review provides an overview of these pathways highlighting, based on preclinical and clinical evidences as well as provocative studies, their potential role as future targets for migraine preventive treatment.

Treatment with the anti-CGRP antibody fremanezumab is successful in the prevention of chronic migraine. In preclinical rat experiments, fremanezumab has been shown to reduce calcitonin gene-related peptide (CGRP) release from trigeminal tissues and the aversive behaviour to noxious facial stimuli, which are characteristic pathophysiological changes accompanying severe primary headaches. To further decipher the effects of fremanezumab underlying these antinociceptive effects in rats, immunohistochemistry and ELISA techniques were used to analyse the content and concentration of CGRP in the trigeminal ganglion as well as the ratio of trigeminal ganglion neurons immunoreactive to CGRP and CGRP receptor components 1-10 days after subcutaneous injection of fremanezumab (30 mg/kg) compared to an isotype control antibody. After fremanezumab treatment, the fraction of trigeminal ganglion neurons immunoreactive to CGRP and the CGRP receptor components calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1) was significantly lowered compared to the control. The content and concentration of CGRP in trigeminal ganglia were not significantly changed. A long-lasting reduction of CGRP receptors expressed in trigeminal afferents may contribute to the attenuation of CGRP signalling and antinociceptive effects of monoclonal anti-CGRP antibodies in rats.

Migraine is a debilitating neurovascular disorder characterized by recurrent headache attacks of moderate to severe intensity. Calcitonin gene-related peptide (GGRP), which is abundantly expressed in trigeminal ganglion (TG) neurons, plays a crucial role in migraine pathogenesis. Cortical spreading depolarization (CSD), the biological correlate of migraine aura, activates the trigeminovascular system. In the present study, we investigated CGRP mRNA expression in TG neurons in a CSD-based mouse migraine model. Our in situ hybridization analysis showed that CGRP mRNA expression was observed in smaller neuronal populations. CSD did not significantly change the density of CGRP mRNA-synthesizing neurons in the ipsilateral TG. However, the cell sizes of CGRP mRNA-synthesizing TG neurons were significantly larger in the 48 h and 72 h post-CSD groups than in the control group. The proportions of CGRP mRNA-synthesizing TG neurons bearing cell diameters less than 14 μm became significantly less at several time points after CSD. In contrast, we found significantly greater proportions of CGRP mRNA-synthesizing TG neurons bearing cell diameters of 14–18 μm at 24 h, 48, and 72 h post-CSD. We deduce that the CSD-induced upward cell size shift in CGRP mRNA-synthesizing TG neurons might be causative of greater disease activity and/or less responsiveness to CGRP-based therapy.

Migraine and neuropathic pain (NP) are evocative of painful, disabling, chronic conditions which exhibit resembling symptoms and thus considered to share a common etiology. Calcitonin gene-related peptide (CGRP) has gained credit as a target for migraine management; nevertheless, the efficacy and the applicability of CGRP modifiers warrant search for more effective therapeutic targets for pain management. This scoping review overviews human studies of common pathogenic factors in migraine and NP to explore potential novel therapeutic targets. CGRP causes inflammation in the meninges; monoclonal antibodies and inhibitors target CGRP. Gluta-mate-induced hyperexcitability and subsequent sensitization are closely linked to an alteration of the tryptophan (Trp)-kynurenine (KYN) metabolic system; the Trp-KYN system may serve as a potential target. Microglial overaction is observed in migraine and NP; modifying the microglial activity may be a possible approach. Cytokine-induced inflammation is a leading hypothesis of the pathogenesis of the conditions; alleviating neuroinflammation may complement a pain-relieving armamentarium. Transient receptor potential (TRP) ion channels evoke the release of several substances; TRP ion channels may potentially emerge as new targets. The endocannabinoid system plays a major role in the pain trafficking pathway; modification of the system may open a new path toward discovery of new analgesics. Here we highlight the mechanism of those common pathogenic factors to explore therapeutic targets for innovative pain management in migraine and NP.