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Calcitonin gene-related peptide (CGRP) and nitric oxide (NO) have been recognized as important mediators in migraine but their mechanisms of action and interaction have not been fully elucidated. Monoclonal anti-CGRP antibodies like fremanezumab are successful preventives of frequent migraine and can be used to study CGRP actions in preclinical experiments. Fremanezumab (30 mg/kg) or an isotype control monoclonal antibody was subcutaneously injected to Wistar rats of both sexes. One to several days later, glyceroltrinitrate (GTN, 5 mg/kg) mimicking nitric oxide (NO) was intraperitoneally injected, either once or for three consecutive days. The trigeminal ganglia were removed to determine the concentration of CGRP using an enzyme-linked immunosorbent assay (ELISA). In one series of experiments, the animals were trained to reach an attractive sugar solution, the access to which could be limited by mechanical or thermal barriers. Using a semi-automated registration system, the frequency of approaches to the source, the residence time at the source, and the consumed solution were registered. The results were compared with previous data of rats not treated with GTN. The CGRP concentration in the trigeminal ganglia was generally higher in male rats and tended to be increased in animals treated once with GTN, whereas the CGRP concentration decreased after repetitive GTN treatment. No significant difference in CGRP concentration was observed between animals having received fremanezumab or the control antibody. Animals treated with GTN generally spent less time at the source and consumed less sugar solution. Without barriers, there was no significant difference between animals having received fremanezumab or the control antibody. Under mechanical barrier conditions, all behavioral parameters tended to be reduced but animals that had received fremanezumab tended to be more active, partly compensating for the depressive effect of GTN. In conclusion, GTN treatment seems to increase the production of CGRP in the trigeminal ganglion independently of the antibodies applied, but repetitive GTN administration may deplete CGRP stores. GTN treatment generally tends to suppress the animals' activity and increase facial sensitivity, which is partly compensated by fremanezumab through reduced CGRP signaling. If CGRP and NO signaling share the same pathway in sensitizing trigeminal afferents, GTN and NO may act downstream of CGRP to increase facial sensitivity. [ABSTRACT FROM AUTHOR]

Treatment with the anti-CGRP antibody fremanezumab is successful in the prevention of chronic and frequent episodic migraine. In preclinical rat experiments, fremanezumab has been shown to reduce calcitonin gene-related peptide (CGRP) release from trigeminal tissues and aversive behaviour to noxious facial stimuli, which are characteristic pathophysiological changes accompanying severe primary headaches. To further decipher the effects of fremanezumab that underlie 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 which are 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 which were 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 in CGRP receptors expressed in trigeminal afferents may contribute to the attenuation of CGRP signalling and antinociceptive effects of monoclonal anti-CGRP antibodies in rats. [ABSTRACT FROM AUTHOR]

Migraine pain is frequently accompanied by cranial hyperalgesia and allodynia. Calcitonin gene-related peptide (CGRP) is implicated in migraine pathophysiology but its role in facial hypersensitivity is not entirely clear. In this study, we investigated if the anti-CGRP monoclonal antibody fremanezumab, which is therapeutically used in chronic and episodic migraines, can modify facial sensitivity recorded by a semi-automatic system. Rats of both sexes primed to drink from a sweet source had to pass a noxious mechanical or heat barrier to reach the source. Under these experimental conditions, animals of all groups tended to drink longer and more when they had received a subcutaneous injection of 30 mg/kg fremanezumab compared to control animals injected with an isotype control antibody 12–13 days prior to testing, but this was significant only for females. In conclusion, anti-CGRP antibody, fremanezumab, reduces facial sensitivity to noxious mechanical and thermal stimulation for more than one week, especially in female rats. Anti-CGRP antibodies may reduce not only headache but also cranial sensitivity in migraineurs. [ABSTRACT FROM AUTHOR]

Migraine headache results from activation of meningeal nociceptors, however, the hypothalamus is activated many hours before the emergence of pain. How hypothalamic neural mechanisms may influence trigeminal nociceptor function remains unknown. Stress is a common migraine trigger that engages hypothalamic dynorphin/kappa opioid receptor (KOR) signalling and increases circulating prolactin. Prolactin acts at both long and short prolactin receptor isoforms that are expressed in trigeminal afferents. Following downregulation of the prolactin receptor long isoform, prolactin signalling at the prolactin receptor short isoform sensitizes nociceptors selectively in females. We hypothesized that stress may activate the kappa opioid receptor on tuberoinfundibular dopaminergic neurons to increase circulating prolactin leading to female-selective sensitization of trigeminal nociceptors through dysregulation of prolactin receptor isoforms. A mouse two-hit hyperalgesic priming model of migraine was used. Repeated restraint stress promoted vulnerability (i.e. first-hit priming) to a subsequent subthreshold (i.e. second-hit) stimulus from inhalational umbellulone, a TRPA1 agonist. Periorbital cutaneous allodynia served as a surrogate of migraine-like pain. Female and male KORCre; R26lsl-Sun1-GFP mice showed a high percentage of KORCre labelled neurons co-localized in tyrosine hydroxylase-positive cells in the hypothalamic arcuate nucleus. Restraint stress increased circulating prolactin to a greater degree in females. Stress-primed, but not control, mice of both sexes developed periorbital allodynia following inhalational umbellulone. Gi-DREADD activation (i.e. inhibition through Gi-coupled signalling) in KORCre neurons in the arcuate nucleus also increased circulating prolactin and repeated chemogenetic manipulation of these neurons primed mice of both sexes to umbellulone. Clustered regularly interspaced short palindromic repeats-Cas9 deletion of the arcuate nucleus KOR prevented restraint stress-induced prolactin release in female mice and priming from repeated stress episodes in both sexes. Inhibition of circulating prolactin occurred with systemic cabergoline, a dopamine D2 receptor agonist, blocked priming selectively in females. Repeated restraint stress downregulated the prolactin receptor long isoform in the trigeminal ganglia of female mice. Deletion of prolactin receptor in trigeminal ganglia by nasal clustered regularly interspaced short palindromic repeats-Cas9 targeting both prolactin receptor isoforms prevented stress-induced priming in female mice. Stress-induced activation of hypothalamic KOR increases circulating prolactin resulting in trigeminal downregulation of prolactin receptor long and pain responses to a normally innocuous TRPA1 stimulus. These are the first data that provide a mechanistic link between stress-induced hypothalamic activation and the trigeminal nociceptor effectors that produce trigeminal sensitization and migraine-like pain. This sexually dimorphic mechanism may help to explain female prevalence of migraine. KOR antagonists, currently in phase II clinical trials, may be useful as migraine preventives in both sexes, while dopamine agonists and prolactin/ prolactin receptor antibodies may improve therapy for migraine, and other stress-related neurological disorders, in females. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies directed against the neuropeptide calcitonin gene-related peptide (CGRP) belong to a new generation of therapeutics that are effective in the prevention of migraine. CGRP, a potent vasodilator, is strongly implicated in the pathophysiology of migraine, but its role remains to be fully elucidated. The hemisected rat head preparation and laser Doppler flowmetry were used to examine the effects on CGRP release from the dura mater and meningeal blood flow of the subcutaneously injected anti-CGRP monoclonal antibody fremanezumab at 30 mg/kg, when compared to an isotype control antibody. Some rats were administered glycerol trinitrate (GTN) intraperitoneally to produce a migraine-like sensitized state. When compared to the control antibody, the fremanezumab injection was followed by reduced basal and capsaicin-evoked CGRP release from day 3 up to 30 days. The difference was enhanced after 4 h of GTN application. The samples from the female rats showed a higher CGRP release compared to that of the males. The increases in meningeal blood flow induced by acrolein (100 µM) and capsaicin (100 nM) were reduced 13–20 days after the fremanezumab injection, and the direct vasoconstrictor effect of high capsaicin (10 µM) was intensified. In conclusion, fremanezumab lowers the CGRP release and lasts up to four weeks, thereby lowering the CGRP-dependent meningeal blood flow. The antibody may not only prevent the released CGRP from binding but may also influence the CGRP release stimulated by noxious agents relevant for the generation of migraine pain. [ABSTRACT FROM AUTHOR]

Objective -- To examine the role of academic librarians in online courses in a university setting. Design -- Survey questionnaire. Setting -- A multi-campus university in the southern United States. Subjects -- Students, faculty, and librarians who had taken, taught, or assisted in fully online courses. Methods -- Email addresses for potential survey participants were provided by the university office of institutional research. The researchers tailored survey questions weto specific subject groups. The surveys took roughly 15 minutes to complete and were open for 1 week following the original email. Surveys included 12 -- 16 questions, depending on the version, and included questions relating to the use of librarians in online courses, the type of assistance they provided, and how assistance was provided (e.g., in person, email, live chat). Question types included yes/no, check-all-that-apply, and open-ended-answer. Main Results -- Of the student responders, 23.24% reported asking a librarian for help with research or an assignment. This help included finding resources (34.48%), database searching (28.57%), and searching the library catalog (20.69%). Help was given over email (28.03%), live chat (31.82%), and in person (17.42%), which was reported to be most helpful by several students. Only 10.61% reported using video-conferencing software such as Zoom. Only 5.88% of faculty reported including a librarian for synchronous instruction in online courses, while 19.12% made use of asynchronous tutorials created by a librarian. The majority of respondents (93.1%) had not worked with an embedded librarian in their courses, and many reported not knowing that it was an option. Instead, faculty perceived librarians to be an outside resource. Both faculty members and students reported a desire for more video tutorials from librarians. Several faculty mentioned wanting a library module that could serve as an introduction to the library, library resources, and basic instruction topics such as citation styles. Conclusion -- While some students and faculty have worked with librarians in online courses and welcomed their involvement, there is room for improvement in library outreach, including how the library communicates with and supports this growing population. [ABSTRACT FROM AUTHOR]

Introduction: Females are thought to have increased risk of developing post-traumatic headache following a traumatic head injury or concussion. However, the processes underlying this susceptibility remain unclear. We previously demonstrated the development of post-traumatic headache-like pain behaviors in a male rat model of mild closed head injury, along with the ability of sumatriptan and an anti-calcitonin-gene-related peptide monoclonal antibody to ameliorate these behaviors. Here, we conducted a follow-up study to explore the development of post-traumatic headache-like behaviors and the effectiveness of these headache therapies in females subjected to the same head trauma protocol.Methods: Adult female Sprague Dawley rats were subjected to a mild closed head injury using a weight-drop device (n = 126), or to a sham procedure (n = 28). Characterization of headache and pain related behaviors included assessment of changes in cutaneous cephalic and extracephalic tactile pain sensitivity, using von Frey monofilaments. Sensitivity to headache/migraine triggers was tested by examining the effect of intraperitoneal administration of a low dose of glyceryl trinitrate (100 µg/kg). Treatments included acute systemic administration of sumatriptan (1 mg/kg) and repeated systemic administration of a mouse anti-calcitonin gene-related peptide monoclonal antibody (30 mg/kg). Serum levels of calcitonin gene-related peptide were measured at baseline and at various time points post head injury in new cohorts of females (n = 38) and males (n = 36).Results: Female rats subjected to a mild closed head injury developed cutaneous mechanical hyperalgesia, which was limited to the cephalic region and was resolved 4 weeks later. Cephalic pain hypersensitivity was ameliorated by treatment with sumatriptan but was resistant to an early and prolonged treatment with the anti-calcitonin gene-related peptide monoclonal antibody. Following the resolution of the head injury-evoked cephalic hypersensitivity, administration of glyceryl trinitrate produced a renewed and pronounced cephalic and extracephalic pain hypersensitivity that was inhibited by sumatriptan, but only partially by the anti-calcitonin gene-related peptide treatment. Calcitonin gene-related peptide serum levels were elevated in females but not in males at 7 days post head injury.Conclusions: Development of post-traumatic headache-like pain behaviors following a mild closed head injury, and responsiveness to treatment in rats is sexually dimorphic. When compared to the data obtained from male rats in the previous study, female rats display a prolonged state of cephalic hyperalgesia, increased responsiveness to a headache trigger, and a poorer effectiveness of an early and prolonged anti-calcitonin gene-related peptide treatment. The increased risk of females to develop post-traumatic headache may be linked to enhanced responsiveness of peripheral and/or central pain pathways and a mechanism independent of peripheral calcitonin gene-related peptide signaling. [ABSTRACT FROM AUTHOR]

Objective - To compare the levels of information literacy, needs, and challenges of undergraduate engineering students with those of practising engineers. Design - Electronic survey. Setting - Large land grant university in the Midwestern United States and multiple locations of a global construction machinery manufacturing company (locations in Asia Pacific, Europe, North America). Subjects - Engineering undergraduates and full-time engineers. Methods - Two voluntary online surveys distributed to (a) students in two undergraduate engineering technology classes and one mechanical engineering class; and (b) to engineers in an online newsletter. None of the questions on the survey were mandatory. Because the call for practising engineers generated a low response rate, direct invitations were sent in batches of 100 to randomly selected engineers from a list provided by the human resources department of the company participating in the study. The surveys were similar but not identical and included multiple choice, Likert scale, and short answer questions. Data analysis included two-sided unpaired sample t-tests (quantitative data) and deductive and inductive content analysis (qualitative data). Main Results - There were 63 students and 134 professional engineers among the respondents. Survey response rates were relatively low (24.3% for students; approximately 4.5% for employees). Students rated themselves higher overall and significantly higher than did engineers on the questions "know where to look for information" (students M = 5.3; engineers M = 4.2) and "identifying the most needed information" (students M = 5.5; engineers M = 4.8) (mean values reported on a 7-point scale). Neither group rated themselves highly on "reflecting on how to improve their performance next time" or "having a highly effective structure for organizing information," though engineers in North America rated themselves significantly higher than those in Asia Pacific on organizing information, knowing where to look for information, and using information to make decisions. Both students and engineers reported often using Google to find information. The library was mentioned by one-half of engineers and one-third of students. Engineers reported consulting with peers for information and making more use of propriety information from within their companies, while students reported using YouTube videos and online forums, as well as news and social media. More than half of students (57%) reported having enough access to information resources, while 67% of engineers felt that they lacked sufficient access. The most common frustration for both groups was locating the information (45% of student responses; 71% of engineer responses). Students reported more frustration with evaluating information (17%) compared to engineers (9%). Conclusion - Engineering students and professional engineers report differences in their levels of confidence in finding information and differences in the complexity of the information landscape. Engineering librarians at the university level can incorporate this knowledge into information literacy courses to help prepare undergraduates for industry. Corporate librarians can use this information to improve methods to support the needs of engineers at all levels of employment. [ABSTRACT FROM AUTHOR]

We appreciate the interest and discussion related to our recently published article "Migraine therapeutics differentially modulate the CGRP pathway" ([1]) by our colleagues, Drs. For example, it has been postulated that the AMY SB 1 sb receptor may be a candidate for CGRP/amylin signaling in the trigeminal ganglia in migraine pathophysiology ([10],[11]) whereas, when expressed in other tissues/organs, the AMY SB 1 sb receptor may mediate different biological functions of amylin ([11]). The investigation of individual receptor responses enabled by I in vitro i studies has uncovered that binding to the human AMY SB 1 sb receptor is a commonality among all the current clinically approved CGRP receptor antagonists: erenumab ([1]), rimegepant ([3]) and ubrogepant ([4]). [Extracted from the article]

Objective - This study explored the role of the public library in the support of patrons of color who experience digital exclusion. Design - In-person and telephone interviews, grounded theory, and critical race theory. Setting - Public libraries in California. Subjects - Persons of color who were active public library technology resource users due to experiencing the digital divide. Methods - In-person, 60- to 90-minute interviews were conducted with participants referred to the author by public librarians at select libraries in California. Sixteen openended questions were asked, relating to demographics, access to technology at home, library technology access and use, technology skills, and thoughts on how libraries could change or improve technology services. A 20- to 30-minute follow-up interview was conducted during the phase of the Covid-19 pandemic when public libraries were closed. Interview transcripts were analyzed by the author, who created a codebook of common themes. Responses were analyzed through the lens of grounded theory and critical race theory. Main Results - Nine participants were recruited; six consented to the first interview and two of the six consented to the second interview. Four of the participants selfreported as Asian, one as Black/African American, and one as Hispanic/Latino American. None of the participants had internet access in their homes, though some reported having laptops or inconsistent cellular service. [ABSTRACT FROM AUTHOR]

Objective -- This study examined the field of medical librarianship as it is currently practiced in Nigeria. Design -- Mixed methods: electronic survey and in-person interview. Setting -- The survey was advertised via an email list and a WhatsApp discussion group, both based in Nigeria. The interviews were requested directly by the authors. Subjects -- Librarians working in medical libraries in Nigeria for the survey; library heads for the interviews. Methods -- The survey was created in Google Forms and shared via the Nigerian Library Association's email discussion list and the WhatsApp Group for the Medial Library Association of Nigeria. Question categories included personal and library demographics, library patronage/social media use, library services for users, and librarians' training and challenges. Most questions were closed-ended. Survey data was analyzed in SPSS for response frequencies and percentages. The interviews were conducted in person. Questions covered topics such as demographics, challenges, and prospects (for medical librarianship in Nigeria). Interview transcriptions underwent thematic content analysis. Main Results -- The majority of the 58 survey respondents (73%) reported seven or more years of medical library experience. There was no consensus on classifications schemes used throughout medical libraries in Nigeria, with 43% using the US National Library of Medicine classification and 32% using the Library of Congress. Social media use also varied, but the majority (approximately 45%) reported using social media less than monthly to promote their libraries or programming. Monographs were the main collection material reported by roughly 35% of respondents. Journals followed at approximately 24% while only 10% reported electronic resources as the main collection material. The majority of respondents (53%) noted that their library did not offer specialized services. Others (31%) reported "selective dissemination of information, current awareness services, or reference services" (p. 402) as specialized services; 7% reported literature searching. The majority of respondents (70-75%) rated their skill levels in evidence based medicine and systematic reviews as beginner/intermediate. Half of respondents reported that their libraries had not held any training programs or seminars for library users in the six months prior. Interviews with library heads revealed that they all had high hopes for the future of medical libraries in Nigeria but also noted many challenges. These included a lack of cooperation between libraries, a lack of interlibrary loan services, budget deficiencies, and insufficient access to the internet. This mirrored survey responses, 50% of which noted access to electronic information was a "significant barrier to improved services" (p. 402) along with a lack of training (53%) and low library usage (57%). Conclusion -- Medical libraries in Nigeria face multiple challenges. Budgetary constraints, a lack of library cooperation, and internet accessibility limit the availability of electronic collections. The authors suggest that library associations in Nigeria focus on education and training opportunities for current and future medical librarians. [ABSTRACT FROM AUTHOR]

Objective -- This study explored reports of burnout among librarians who assist with systematic review preparation. Design -- Electronic survey (Copenhagen Burnout Inventory). Setting -- The survey was advertised via three email discussion lists based in the United States of America. Subjects -- The study surveyed 198 librarians and information specialists who support the systematic review process. Of these, 166 completed the personal burnout scale, 159 completed the work burnout scale, and 151 completed the client burnout scale. Methods -- The Copenhagen Burnout Inventory (CBI) is a validated survey that includes three separate scales: personal burnout, work-related burnout, and client- related burnout. The end of the survey addressed demographics, including questions on the respondents' involvement with systematic reviews. Survey questions use a 0 to 100 rating scale, with 0 indicating Never/To a Low Degree and 100 indicating Always/To a High Degree. The researchers shared the survey to the email discussion lists MEDLIB-L and DOCLINE and advertised it on the Medical Library Association (MLA) News. Survey answers were collected using Qualtrics Survey Software. Once emailed, the survey remained open for one month. Data was coded in Excel and analysis included scoring following the CBI metrics, as well as TukeyHSD and Kruskal-Wallis tests to determine differences in demographic groups. Main Results -- Reported burnout levels were significantly lower for those who spend more than 80% of their time helping with systematic reviews compared to those who spend less than 10%. The consistent use of a systematic review support tool was also associated with significantly lower burnout levels. Other comparisons were not significant. The average overall response score for personal burnout was 48.6. The average score for work-related burnout was 46.4 and the average score for client-related burnout was 32.5. Reference librarians reported the highest average total burnout scores (47.1), while research librarians had the lowest (37.7). Conclusion -- Consistency, either in time spent dedicated to systematic reviews or in the use of a support tool, was associated with lower levels of burnout among librarians and information specialists. The authors suggest that these results could inform ways of improving burnout among those assisting with systematic reviews. [ABSTRACT FROM AUTHOR]

Huntingtin-associated protein 1 (HAP1) was initially identified as a binding partner of huntingtin, mutations in which underlie Huntington's disease. Subcellular localization and protein interaction data indicate that HAP1 may be important in vesicle trafficking, cell signalling and receptor internalization. In this study, a proteomics approach was used for the identification of novel HAP1-interacting partners to attempt to shed light on the physiological function of HAP1. Using affinity chromatography with HAP1-GST protein fragments bound to Sepharose columns, this study identified a number of trafficking-related proteins that bind to HAP1. Interestingly, many of the proteins that were identified by mass spectrometry have trafficking-related functions and include the clathrin light chain B and Sec23A, an ER to Golgi trafficking vesicle coat component. Using co-immunoprecipitation and GST-binding assays the association between HAP1 and clathrin light chain B has been validated in vitro . This study also finds that HAP1 co-localizes with clathrin light chain B. In line with a physiological function of the HAP1-clathrin interaction this study detected a dramatic reduction in vesicle retrieval and endocytosis in adrenal chromaffin cells. Furthermore, through examination of transferrin endocytosis in HAP1 −/− cortical neurons, this study has determined that HAP1 regulates neuronal endocytosis. In this study, the interaction between HAP1 and Sec23A was also validated through endogenous co-immunoprecipitation in rat brain homogenate. Through the identification of novel HAP1 binding partners, many of which have putative trafficking roles, this study provides us with new insights into the mechanisms underlying the important physiological function of HAP1 as an intracellular trafficking protein through its protein-protein interactions. [ABSTRACT FROM AUTHOR]

Huntingtin-associated protein-1 ( HAP1) is involved in intracellular trafficking, vesicle transport, and membrane receptor endocytosis. However, despite such diverse functions, the role of HAP1 in the synaptic vesicle ( SV) cycle in nerve terminals remains unclear. Here, we report that HAP1 functions in SV exocytosis, controls total SV turnover and the speed of vesicle fusion in nerve terminals and regulates glutamate release in cortical brain slices. We found that HAP1 interacts with synapsin I, an abundant neuronal phosphoprotein that associates with SVs during neurotransmitter release and regulates synaptic plasticity and neuronal development. The interaction between HAP1 with synapsin I was confirmed by reciprocal co-immunoprecipitation of the endogenous proteins. Furthermore, HAP1 co-localizes with synapsin I in cortical neurons as discrete puncta. Interestingly, we find that synapsin I localization is specifically altered in Hap1−/− cortical neurons without an effect on the localization of other SV proteins. This effect on synapsin I localization was not because of changes in the levels of synapsin I or its phosphorylation status in Hap1−/− brains. Furthermore, fluorescence recovery after photobleaching in transfected neurons expressing enhanced green fluorescent protein-synapsin Ia demonstrates that loss of HAP1 protein inhibits synapsin I transport. Thus, we demonstrate that HAP1 regulates SV exocytosis and may do so through binding to synapsin I. [ABSTRACT FROM AUTHOR]

How fusion pore formation during exocytosis affects the subsequent release of vesicle contents remains incompletely understood. It is unclear if the amount released per vesicle is dependent upon the nature of the developing fusion pore and whether full fusion and transient kiss and run exocytosis are regulated by similar mechanisms. We hypothesise that if consistent relationships exist between these aspects of exocytosis then they will remain constant across any age. Using amperometry in mouse chromaffin cells we measured catecholamine efflux during single exocytotic events at P0, 1month and 6 months. At all ages we observed full fusion (amperometric spike only), full fusion preceded by fusion pore flickering (prespike foot (PSF) signal followed by a spike) and pure ''kiss and run'' exocytosis (represented by stand alone foot (SAF) signals). We observe age-associated increases in the size of all 3 modes of fusion but these increases occur at different ages. The release probability of PSF signals or full spikes alone doesn't alter across any age in comparison with an age-dependent increase in the incidence of ''kiss and run'' type events. However, the most striking changes we observe are age-associated changes in the relationship between vesicle size and the membrane bending energy required for exocytosis. Our data illustrates that vesicle size does not regulate release probability, as has been suggested, that membrane elasticity or flexural rigidity change with age and that the mechanisms controlling full fusion may differ from those controlling ''kiss and run'' fusion. [ABSTRACT FROM AUTHOR]

The precise role played by serotonin (5-HT) in taste--an issue of great interest given the involvement of serotonin in human sensory and eating disorders--is a matter of considerable debate, perhaps because of the variety of methodologies that have been brought to bear by different researchers. Here, we use multiple methods to reveal the motivational mechanism whereby 5-HT1A receptor activation modulates drinking behavior. Subcutaneous injections of the selective 5-HT1A agonist 8-hydroxy-2-di-npropylamino -tetralin (8-OH-DPAT), a drug that reduces 5-HT release by acting on presynaptic auto-receptors, dose-dependently increased consumption of 0.45M NaC1 in a one-bottle test. In a two-bottle test, however, 8-OH-DPAT-treated animals (30 µg/kg/ml) demonstrated decreased NaC1 preference --although our detection of this effect was obscured by adaptation to the drug across days. Rats' performance in a brief access test confirmed that 8-OH-DPAT decreased preference for saline by both increasing water consumption and decreasing NaC1 consumption. Finally, taste reactivity tests demonstrated that the latter result does not reflect decreased NaC1 palatability. Overall, the results suggest that 8-OH-DPAT-induced 5-HT hypofunction increases thirst without substantially affecting the palatability of NaC1. [ABSTRACT FROM AUTHOR]

Background: The clinical efficacy of migraine therapeutic agents directed towards the calcitonin-gene related peptide (CGRP) pathway has confirmed the key role of this axis in migraine pathogenesis. Three antibodies against CGRP - fremanezumab, galcanezumab and eptinezumab - and one antibody against the CGRP receptor, erenumab, are clinically approved therapeutics for the prevention of migraine. In addition, two small molecule CGRP receptor antagonists, ubrogepant and rimegepant, are approved for acute migraine treatment. Targeting either the CGRP ligand or receptor is efficacious for migraine treatment; however, a comparison of the mechanism of action of these therapeutic agents is lacking in the literature.Methods: To gain insights into the potential differences between these CGRP pathway therapeutics, we compared the effect of a CGRP ligand antibody (fremanezumab), a CGRP receptor antibody (erenumab) and a CGRP receptor small molecule antagonist (telcagepant) using a combination of binding, functional and imaging assays.Results: Erenumab and telcagepant antagonized CGRP, adrenomedullin and intermedin cAMP signaling at the canonical human CGRP receptor. In contrast, fremanezumab only antagonized CGRP-induced cAMP signaling at the human CGRP receptor. In addition, erenumab, but not fremanezumab, bound and internalized at the canonical human CGRP receptor. Interestingly, erenumab also bound and internalized at the human AMY1 receptor, a CGRP receptor family member. Both erenumab and telcagepant antagonized amylin-induced cAMP signaling at the AMY1 receptor while fremanezumab did not affect amylin responses.Conclusion: The therapeutic effect of agents targeting the CGRP ligand versus receptor for migraine prevention (antibodies) or acute treatment (gepants) may involve distinct mechanisms of action. These findings suggest that differing mechanisms could affect efficacy, safety, and/or tolerability in migraine patients. [ABSTRACT FROM AUTHOR]

Background: Acute and persistent post-traumatic headache are often debilitating consequences of traumatic brain injury. Underlying physiological mechanisms of post-traumatic headache and its persistence remain unknown, and there are currently no approved therapies for these conditions. Post-traumatic headache often presents with a migraine-like phenotype. As calcitonin-gene related peptide promotes migraine headache, we explored the efficacy and timing of intervention with an anti- calcitonin-gene related peptide monoclonal antibody in novel preclinical models of acute post-traumatic headache and persistent post-traumatic headache following a mild traumatic brain injury event in mice.Methods: Male, C57Bl/6 J mice received a sham procedure or mild traumatic brain injury resulting from a weight drop that allowed free head rotation while under minimal anesthesia. Periorbital and hindpaw tactile stimulation were used to assess mild traumatic brain injury-induced cutaneous allodynia. Two weeks after the injury, mice were challenged with stress, a common aggravator of migraine and post-traumatic headache, by exposure to bright lights (i.e. bright light stress) and cutaneous allodynia was measured hourly for 5 hours. A murine anti- calcitonin-gene related peptide monoclonal antibody was administered after mild traumatic brain injury at different time points to allow evaluation of the consequences of either early and sustained calcitonin-gene related peptide sequestration or late administration only prior to bright light stress.Results: Mice with mild traumatic brain injury, but not a sham procedure, exhibited both periorbital and hindpaw cutaneous allodynia that resolved by post-injury day 13. Following resolution of injury-induced cutaneous allodynia, exposure to bright light stress re-instated periorbital and hindpaw cutaneous allodynia in injured, but not sham mice. Repeated administration of anti-calcitonin-gene related peptide monoclonal antibody at 2 hours, 7 and 14 days post mild traumatic brain injury significantly attenuated the expression of cutaneous allodynia when evaluated over the 14-day post injury time course and also prevented bright light stress-induced cutaneous allodynia in injured mice. Administration of anti-calcitonin-gene related peptide monoclonal antibody only at 2 hours and 7 days after mild traumatic brain injury blocked injury-induced cutaneous allodynia and partially prevented bright light stress-induced cutaneous allodynia. A single administration of anti-calcitonin-gene related peptide monoclonal antibody after the resolution of the peak injury-induced cutaneous allodynia, but prior to bright light stress challenge, did not prevent bright light stress-induced cutaneous allodynia.Conclusions: We used a clinically relevant mild traumatic brain injury event in mice along with a provocative stimulus as novel models of acute post-traumatic headache and persistent post-traumatic headache. Following mild traumatic brain injury, mice demonstrated transient periorbital and hindpaw cutaneous allodynia suggestive of post-traumatic headache-related pain and establishment of central sensitization. Following resolution of injury-induced cutaneous allodynia, exposure to bright light stress re-established cutaneous allodynia, suggestive of persistent post-traumatic headache-related pain. Continuous early sequestration of calcitonin-gene related peptide prevented both acute post-traumatic headache and persistent post-traumatic headache. In contrast, delayed anti-calcitonin-gene related peptide monoclonal antibody treatment following establishment of central sensitization was ineffective in preventing persistent post-traumatic headache. These observations suggest that mechanisms involving calcitonin-gene related peptide underlie the expression of acute post-traumatic headache, and drive the development of central sensitization, increasing vulnerability to headache triggers and promoting persistent post-traumatic headache. Early and continuous calcitonin-gene related peptide blockade following mild traumatic brain injury may represent a viable treatment option for post-traumatic headache and for the prevention of post-traumatic headache persistence.Abbreviations: CA Cutaneous allodynia CGRP Calcitonin gene-related peptide mTBI Mild traumatic brain injury PTH Post-traumatic headache APTH Acute post-traumatic headache PPTH Persistent post-traumatic headache. [ABSTRACT FROM AUTHOR]

Irritable bowel syndrome (IBS) and bladder pain syndrome/interstitial cystitis (BPS/IC) are comorbid visceral pain disorders seen commonly in women with unknown etiology and limited treatment options and can involve visceral organ cross-sensitization. Calcitonin gene-related peptide (CGRP) is a mediator of nociceptive processing and may serve as a target for therapy. In three rodent models, we employed a monoclonal anti-CGRP F(ab') 2 to investigate the hypothesis that visceral organ cross-sensitization is mediated by abnormal CGRP signaling. Visceral organ cross-sensitization was induced in adult female rats via transurethral infusion of protamine sulfate (PS) into the urinary bladder or infusion into the colon of trinitrobenzene sulfonic acid (TNBS). Colonic sensitivity was assessed via the visceromotor response to colorectal distension (CRD). Bladder sensitivity was assessed as the frequency of abdominal withdrawal reflexes to von Frey filaments applied to the suprapubic region. PS- or TNBS-induced changes in colonic and bladder permeability were investigated in vitro via quantification of transepithelial electrical resistance (TEER). Peripheral administration of an anti-CGRP F(ab') 2 inhibited PS-induced visceral pain behaviors and colon hyperpermeability. Similarly, TNBS-induced pain behaviors and colon and bladder hyperpermeability were attenuated by anti-CGRP F(ab') 2 treatment. PS into the bladder or TNBS into the colon significantly increased the visceromotor response to CRD and abdominal withdrawal reflexes to suprapubic stimulation and decreased bladder and colon TEER. These findings suggest an important role of peripheral CGRP in visceral nociception and organ cross-sensitization and support the evaluation of CGRP as a therapeutic target for visceral pain in patients with IBS and/or BPS/IC. SIGNIFICANCE STATEMENT: A monoclonal antibody against calcitonin gene-related peptide (CGRP) was found to reduce concomitant colonic and bladder hypersensitivity and hyperpermeability. The results of this study suggest that CGRP-targeting antibodies, in addition to migraine prevention, may provide a novel treatment strategy for multiorgan abdominopelvic pain following injury or inflammation., (Copyright © 2023 by The Author(s).)

Calcitonin gene-related peptide (CGRP) pathway-targeted treatments have been shown to be efficacious in the prevention of episodic and chronic migraine. Currently approved therapies include monoclonal antibodies (mAbs) that target CGRP (eptinezumab, fremanezumab, and galcanezumab) and the CGRP receptor (erenumab), and small molecule CGRP receptor antagonists (atogepant and rimegepant). While CGRP pathway-targeted treatments are generally well-tolerated, in a review article by Holzer and Holzer-Petsche published in the January 2022 issue of Frontiers in Physiology the authors discussed the role of the CGRP pathway in gastrointestinal physiology, with a specific focus on constipation associated with the use of CGRP pathway-targeted treatments. The authors state that real-world surveys have shown constipation to be a "major adverse event" reported in "more than 50% of patients treated with erenumab, fremanezumab or galcanezumab." As described in the current commentary, the limited data from the cited references in the review article by Holzer and Holzer-Petsche do not support that statement., Competing Interests: KM and JS were employed by the company of Teva Pharmaceuticals. MO, VRC, LK, and XN were employed by the company of Teva Branded Pharmaceutical Products R&D, Inc. YK was employed by the company of Teva Pharmaceutical Industries Ltd. KC was formerly employed by the company of Teva Branded Pharmaceutical Products R&D, Inc. Medical writing and editorial support were provided by Tamara Stevenson, PhD, of Lumanity Communications, Inc., and were funded by Teva Pharmaceutical Industries., (Copyright © 2022 Mackenzie, Ortega, Kessler, Campos, Krasenbaum, Carr, Ning and Stratton.)

Migraine headache results from activation of meningeal nociceptors, however, the hypothalamus is activated many hours before the emergence of pain. How hypothalamic neural mechanisms may influence trigeminal nociceptor function remains unknown. Stress is a common migraine trigger that engages hypothalamic dynorphin/kappa opioid receptor (KOR) signalling and increases circulating prolactin. Prolactin acts at both long and short prolactin receptor isoforms that are expressed in trigeminal afferents. Following downregulation of the prolactin receptor long isoform, prolactin signalling at the prolactin receptor short isoform sensitizes nociceptors selectively in females. We hypothesized that stress may activate the kappa opioid receptor on tuberoinfundibular dopaminergic neurons to increase circulating prolactin leading to female-selective sensitization of trigeminal nociceptors through dysregulation of prolactin receptor isoforms. A mouse two-hit hyperalgesic priming model of migraine was used. Repeated restraint stress promoted vulnerability (i.e. first-hit priming) to a subsequent subthreshold (i.e. second-hit) stimulus from inhalational umbellulone, a TRPA1 agonist. Periorbital cutaneous allodynia served as a surrogate of migraine-like pain. Female and male KORCre; R26lsl-Sun1-GFP mice showed a high percentage of KORCre labelled neurons co-localized in tyrosine hydroxylase-positive cells in the hypothalamic arcuate nucleus. Restraint stress increased circulating prolactin to a greater degree in females. Stress-primed, but not control, mice of both sexes developed periorbital allodynia following inhalational umbellulone. Gi-DREADD activation (i.e. inhibition through Gi-coupled signalling) in KORCre neurons in the arcuate nucleus also increased circulating prolactin and repeated chemogenetic manipulation of these neurons primed mice of both sexes to umbellulone. Clustered regularly interspaced short palindromic repeats-Cas9 deletion of the arcuate nucleus KOR prevented restraint stress-induced prolactin release in female mice and priming from repeated stress episodes in both sexes. Inhibition of circulating prolactin occurred with systemic cabergoline, a dopamine D2 receptor agonist, blocked priming selectively in females. Repeated restraint stress downregulated the prolactin receptor long isoform in the trigeminal ganglia of female mice. Deletion of prolactin receptor in trigeminal ganglia by nasal clustered regularly interspaced short palindromic repeats-Cas9 targeting both prolactin receptor isoforms prevented stress-induced priming in female mice. Stress-induced activation of hypothalamic KOR increases circulating prolactin resulting in trigeminal downregulation of prolactin receptor long and pain responses to a normally innocuous TRPA1 stimulus. These are the first data that provide a mechanistic link between stress-induced hypothalamic activation and the trigeminal nociceptor effectors that produce trigeminal sensitization and migraine-like pain. This sexually dimorphic mechanism may help to explain female prevalence of migraine. KOR antagonists, currently in phase II clinical trials, may be useful as migraine preventives in both sexes, while dopamine agonists and prolactin/ prolactin receptor antibodies may improve therapy for migraine, and other stress-related neurological disorders, in females., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Irritable bowel syndrome (IBS) is a brain-gut disorder characterized by abdominal pain and altered bowel habits. Although the etiology of IBS remains unclear, stress in adulthood or in early life has been shown to be a significant factor in the development of IBS symptomatology. Evidence suggests that aberrant calcitonin gene-related peptide (CGRP) signaling may be involved in afferent sensitization and visceral organ hypersensitivity. Here, we used a monoclonal anti-CGRP divalent antigen-binding fragment [F(ab') 2 ] antibody to test the hypothesis that inhibition of peripheral CGRP signaling reverses colonic hypersensitivity induced by either chronic adult stress or early life stress. A cohort of adult male rats was exposed to repeated water avoidance stress. Additionally, a second cohort consisting of female rats was exposed to a female-specific neonatal odor-attachment learning paradigm of unpredictable early life stress. Colonic sensitivity was then assessed in adult animals via behavioral responses to colorectal distension (CRD). To analyze spinal nociceptive signaling in response to CRD, dorsal horn extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was measured via immunohistochemistry. Repeated psychologic stress in adulthood or unpredictable stress in early life induced colonic hypersensitivity and enhanced evoked ERK1/2 phosphorylation in the spinal cord after CRD in rats. These phenotypes were reversed by administration of a monoclonal anti-CGRP F(ab') 2 fragment antibody. Stress-induced changes in visceral sensitivity and spinal nociceptive signaling were reversed by inhibition of peripheral CGRP signaling, which suggests a prominent role for CGRP in central sensitization and the development of stress-induced visceral hypersensitivity. SIGNIFICANCE STATEMENT: Targeting peripheral calcitonin gene-related peptide (CGRP) with a monoclonal anti-CGRP divalent antigen-binding fragment antibody reduced central sensitization and attenuated colonic hypersensitivity induced by either chronic adult stress or early life stress. CGRP-targeting antibodies are approved for migraine prevention, and the results of this study suggest that targeting CGRP may provide a novel treatment strategy for irritable bowel syndrome-related, stress-induced visceral pain., (Copyright © 2021 The Author(s).)