[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to use protein array analysis to investigate temporal regulation of stimulated cytokine expression in trigeminal ganglia and the spinal trigeminal nucleus in response to co-treatment of sumatriptan and naproxen sodium or individual drug.
Activation of neurons and glia in trigeminal ganglia and the spinal trigeminal nucleus leads to increased levels of cytokines that promote peripheral and central sensitization, which are key events in migraine pathology. While recent clinical studies have provided evidence that a combination of sumatriptan and naproxen sodium is more efficacious in treating migraine than either drug alone, it is not well understood why the combination therapy is superior to monotherapy.
Male Sprague-Dawley rats were left untreated (control), injected with capsaicin, or pretreated with sumatriptan/naproxen, sumatriptan, or naproxen for 1 hour prior to capsaicin. Trigeminal ganglia and the spinal trigeminal nucleus were isolated 2 and 24 hours after capsaicin or drug treatment, and levels of 90 proteins were determined using a RayBio® Label-Based Rat Antibody Array (RayBiotech, Norcross, GA, USA).
Capsaicin stimulated a >3-fold increase in expression of the majority of cytokines in trigeminal ganglia at 2 hours that was sustained at 24 hours. Significantly, treatment with sumatriptan/naproxen almost completely abolished the stimulatory effects of capsaicin at 2 and 24 hours. Capsaicin stimulated >3-fold expression of more proteins in the spinal trigeminal nucleus at 24 hours when compared to 2 hours. Similarly, sumatriptan/naproxen abolished capsaicin stimulation of proteins in the spinal trigeminal nucleus at 2 hours and greatly suppressed protein expression 24 hours post-capsaicin injection. Interestingly, treatment with sumatriptan alone suppressed expression of different cytokines in trigeminal ganglia and the spinal trigeminal nucleus than repressed by naproxen sodium.
We found that the combination of sumatriptan/naproxen was effective in blocking capsaicin stimulation of pro-inflammatory proteins implicated in the development of peripheral and central sensitization in response to capsaicin activation of trigeminal neurons. Based on our findings that sumatriptan and naproxen regulate expression of different proteins in trigeminal ganglia and the spinal trigeminal nucleus, we propose that these drugs function on therapeutically distinct cellular targets to suppress inflammation and pain associated with migraine.
Headache The Journal of Head and Face Pain 12/2011; 52(1):80-9. · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Based on preclinical and clinical studies, the neuropeptide calcitonin gene-related peptide (CGRP) is proposed to play a central role in the underlying pathology of migraine. CGRP and its receptor are widely expressed in both the peripheral and central nervous systems by multiple cell types involved in the regulation of inflammatory and nociceptive responses. Peripheral release of CGRP from trigeminal nerve fibres within the dura and from the cell body of trigeminal ganglion neurons is likely to contribute to peripheral sensitization of trigeminal nociceptors. Similarly, the release of CGRP within the trigeminal nucleus caudalis can facilitate activation of nociceptive second-order neurons and glial cells. Thus, CGRP is involved in the development and maintenance of persistent pain, central sensitization and allodynia, events characteristic of migraine pathology. In contrast, CGRP release within the brain is likely to function in an anti-nociceptive capacity. Given the role of CGRP in migraine pathology, the potential of CGRP receptor antagonists in the treatment of migraine has been investigated. Towards this end, the non-peptide CGRP receptor antagonists olcegepant and telcagepant have been shown to be effective in the acute treatment of migraine. While telcagepant is being pursued as a frontline abortive migraine drug in a phase III clinical trial, an oral formulation of a novel CGRP receptor antagonist, BI 44370, is currently in phase II clinical trials. Encouragingly, data from clinical studies on these compounds have clearly demonstrated the potential therapeutic benefit of this class of drugs and support the future development of CGRP receptor antagonists to treat migraine and possibly other types of chronic pain.
[Show abstract][Hide abstract] ABSTRACT: To measure prostaglandin levels in the saliva of individuals during menstrual migraine associated with dysmenorrhea (MMaD) and in response to treatment with a single tablet combination of sumatriptan succinate and naproxen sodium.
Prostaglandins are thought to play a role in MMaD as elevated serum prostaglandin levels have been reported during attacks of menstrual migraine and are increased in the menstrual fluid of women with dysmenorrhea. While triptans are the primary line of migraine treatment, nonsteriodal anti-inflammatory drugs are the most commonly prescribed therapy for dysmenorrhea symptoms. Data from recent clinical studies have provided evidence that treatment with a single tablet combination of sumatriptan and naproxen sodium is an effective abortive therapy for attacks of MMaD.
Women diagnosed with MMaD were treated with a sumatriptan succinate and naproxen sodium single tablet combination or placebo at time of migraine attack. Saliva samples were collected at time of attack as well as 2 and 4 hours after treatment. PGD(2), PGE(2), PGF(2), PGI(2), and TXA(2) levels were determined by enzyme-linked immunosorbent assay.
Elevated levels of PGD(2), PGF(2), and TXA(2) at 2 and 4 hours and PGE(2) at 4 hours were found in saliva obtained from placebo subjects when compared with onset of attack levels. However, in subjects treated with a single tablet combination of sumatriptan and naproxen sodium, the levels of PGD(2), PGF(2), and PGE(2) were not elevated at either time point while TXA(2) levels were still elevated at 4 hours.
Data from this pilot study provide evidence that saliva levels of several prostaglandins increase during attacks of MMaD and that treatment with a single tablet combination of sumatriptan and naproxen sodium prevents elevation of prostaglandin levels.
Headache The Journal of Head and Face Pain 03/2010; 50(5):844-51. · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Calcitonin gene-related peptide (CGRP) is a multifunctional neuropeptide implicated in inflammatory diseases involving trigeminal ganglion nerve activation. Within trigeminal ganglia, satellite glia and Schwann cells are found in close association with neuronal cell bodies and fibers, respectively, and are known to express functional CGRP receptors. The goal of this study was to use array analysis to provide a more comprehensive understanding of CGRP regulation of inflammatory proteins and genes in trigeminal glia. Primary trigeminal ganglia cultures enriched for glia were treated with 500 nM CGRP for 8 or 24h. CGRP caused a >3-fold increase in the level of 19 cytokines 8h after CGRP treatment and the levels of each of these cytokines remained significantly elevated over basal unstimulated levels at 24h. While mRNA levels of many genes involved in mitogen-activated protein (MAP) kinase signaling were increased 8h after CGRP treatment, the number of responsive genes was greatly increased at 24h. Specifically, CGRP was shown to temporally regulate expression of multiple MAP kinases as well as numerous MAP kinase-responsive genes including transcription factors, scaffold/anchoring proteins, and cell cycle proteins. Thus, our data provide evidence of an emerging role of CGRP as an important modulator of trigeminal ganglion glia by stimulating cytokine release as well as inducing expression of a diverse array of proteins involved in MAP kinase signaling.
[Show abstract][Hide abstract] ABSTRACT: (1) To measure calcitonin gene-related peptide (CGRP) levels in the saliva of individuals with migraine during the premonitory period, mild headache, moderate to severe headache, and post-resolution phases as compared with baseline (interictal) CGRP levels. (2) To correlate response to rizatriptan administered during moderate headache with levels of CGRP levels measured in saliva.
CGRP is implicated in the underlying pathophysiology of migraine. To date no study has measured changes of saliva CGRP through the clinical evolution of a migraine attack and correlated saliva CGRP levels to clinical response to therapy.
Data were summarized using tables and descriptive statistics. Statistical analysis was performed with the non-parametric signed-rank test using Minitab15 statistical software. Results of statistical analyses were considered significant at P < .05. Responding subjects were defined as those who were symptom free at the time of the last collected saliva sample and did not have to rescue. Non-responding subjects were defined as those who rescued with an additional dose of rizatriptan or another medication or who were not symptom free at the end of the collection period.
Statistically significant elevations of CGRP were noted in the premonitory, mild headache, and moderate to severe headache phase of the migraine compared with baseline (interictal) levels. A better therapeutic response to rizatriptan was observed in subjects with elevated saliva CGRP levels. Successful treatment with rizatriptan correlated with saliva CGRP levels returning to near baseline levels. In the rizatriptan non-responder group, no significant change in saliva CGRP levels was found at any phase of the migraine attack.
Elevation of saliva CGRP is predictive of responsiveness to rizatriptan. In the rizatriptan responsive population, CGRP levels are elevated beginning with the premonitory period and throughout mild and moderate/severe headache. Successful response to rizatriptan correlated with return of saliva CGRP levels to near baseline (interictal) values.
Headache The Journal of Head and Face Pain 10/2009; 49(9):1258-66. · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Clinical and basic science data support an integral role of calcitonin gene-related peptide (CGRP) in the pathophysiology of temporomandibular joint disorders. Recently, we have shown that CGRP can stimulate the synthesis and release of nitric oxide (NO) from trigeminal ganglion glial cells. The goal of this study was to determine the role of mitogen-activated protein kinase (MAPK) signaling pathways in CGRP regulation of iNOS expression and NO release from cultured trigeminal ganglion glial cells from Sprague-Dawley rats. CGRP treatment for 2 h significantly increased activity of the MAPK reporter genes, Elk, ATF-2, and CHOP. In addition, CGRP increased nuclear staining for the active forms of the MAPKs: extracellular signal-regulated kinase, c-Jun amino-terminal kinase, and p38. This stimulatory event was not observed in cultures pre-treated with the CGRP receptor antagonist peptide CGRP(8-37). Similarly, pre-treatment with selective MAPK inhibitors repressed increases in reporter gene activity as well as CGRP-induced increases in iNOS expression and NO release mediated by MAPKs. In addition, over-expression of MAPK kinase 1 (MEK1), MEK3, MEK6, and MEK kinase significantly increased iNOS expression and NO production in glial cells. Results from our study provide evidence that CGRP binding to its receptor can stimulate iNOS gene expression via activation of MAPK pathways in trigeminal ganglion glial cells.
Journal of Neurochemistry 06/2009; 110(3):811-21. · 3.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Clinical and basic science data support an integral role of calcitonin gene-related peptide (CGRP) in migraine pathology. Following trigeminal nerve activation, afferent release of CGRP causes vasodilation while efferent release leads to pain. Although CGRP can also be secreted from cell bodies of trigeminal neurons located within the ganglion, the function of CGRP released in the ganglion is poorly understood. Initially, we showed that SNAP-25, a protein required for CGRP release, was localized in cell bodies of trigeminal ganglia neurons. We also found that satellite glial cells in the ganglia express the CGRP1 receptor protein RAMP1. To determine whether CGRP could directly activate glial cells, primary cultures of rat trigeminal ganglia were utilized to study the effects of CGRP on glial nitric oxide (NO) synthesis and release. Under our culture conditions, >95% of the cells expressed glial fibrillary acidic protein and RAMP1. While weak iNOS staining was observed in glia under basal conditions, CGRP treatment greatly increased glial iNOS expression and NO release. This stimulatory effect was blocked by the CGRP1 receptor antagonist, CGRP(8-37) peptide. Treatment of glial cultures with forskolin or cAMP also increased iNOS expression and stimulated NO release to levels similar to CGRP. To our knowledge, this is the first evidence that activation of CGRP1 receptors regulates glial iNOS and NO release. We propose that following trigeminal nerve activation, CGRP secretion from neuronal cell bodies activates satellite glial cells that release NO and initiate inflammatory events in the ganglia that contribute to peripheral sensitization in migraine.
Brain Research 03/2008; 1196:22-32. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cocoa bean preparations were first used by the ancient Maya and Aztec civilizations of South America to treat a variety of medical ailments involving the cardiovascular, gastrointestinal, and nervous systems. Diets rich in foods containing abundant polyphenols, as found in cocoa, underlie the protective effects reported in chronic inflammatory diseases. Release of calcitonin gene-related peptide (CGRP) from trigeminal nerves promotes inflammation in peripheral tissues and nociception.
To determine whether a methanol extract of Theobroma cacao L. (Sterculiaceae) beans enriched for polyphenols could inhibit CGRP expression, both an in vitro and an in vivo approach was taken.
Treatment of rat trigeminal ganglia cultures with depolarizing stimuli caused a significant increase in CGRP release that was repressed by pretreatment with Theobroma cacao extract. Pretreatment with Theobroma cacao was also shown to block the KCl- and capsaicin-stimulated increases in intracellular calcium. Next, the effects of Theobroma cacao on CGRP levels were determined using an in vivo model of temporomandibular joint (TMJ) inflammation. Capsaicin injection into the TMJ capsule caused an ipsilateral decrease in CGRP levels. Theobroma cacao extract injected into the TMJ capsule 24h prior to capsaicin treatment repressed the stimulatory effects of capsaicin.
Our results demonstrate that Theobroma cacao extract can repress stimulated CGRP release by a mechanism that likely involves blockage of calcium channel activity. Furthermore, our findings suggest that the beneficial effects of diets rich in cocoa may include suppression of sensory trigeminal nerve activation.
Journal of Ethnopharmacology 02/2008; 115(2):238-48. · 2.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to determine whether the physiological effects of carbon dioxide (CO(2)) involve regulation of CGRP secretion from trigeminal sensory neurons.
The neuropeptide calcitonin gene-related peptide (CGRP) is implicated in the pathophysiology of allergic rhinosinusitis and migraine. Recent clinical evidence supports the use of noninhaled intranasal delivery of 100% CO(2) for treatment of these diseases. Patients report 2 distinct physiological events: first, a short duration stinging or burning sensation within the nasal mucosa, and second, alleviation of primary symptoms.
Primary cultures of rat trigeminal ganglia were utilized to investigate the effects of CO(2) on CGRP release stimulated by a depolarizing stimulus (KCl), capsaicin, nitric oxide, and/or protons. The amount of CGRP secreted into the culture media was determined using a CGRP-specific radioimmunoassay. Intracellular pH and calcium levels were measured in cultured trigeminal neurons in response to CO(2) and stimulatory agents using fluorescent imaging techniques.
Incubation of primary trigeminal ganglia cultures at pH 6.0 or 5.5 was shown to significantly stimulate CGRP release. Similarly, CO(2) treatment of cultures caused a time-dependent acidification of the media, achieving pH values of 5.5-6 that stimulated CGRP secretion. In addition, KCl, capsaicin, and a nitric oxide donor also caused a significant increase in CGRP release. Interestingly, CO(2) treatment of cultures under isohydric conditions, which prevents extracellular acidification while allowing changes in PCO(2) values, significantly repressed the stimulatory effects of KCl, capsaicin, and nitric oxide on CGRP secretion. We found that CO(2) treatment under isohydric conditions resulted in a decrease in intracellular pH and inhibition of the KCl- and capsaicin-mediated increases in intracellular calcium.
Results from this study provide the first evidence of a unique regulatory mechanism by which CO(2) inhibits sensory nerve activation, and subsequent neuropeptide release. Furthermore, the observed inhibitory effect of CO(2) on CGRP secretion likely involves modulation of calcium channel activity and changes in intracellular pH.
Headache The Journal of Head and Face Pain 01/2007; 47(10):1385-97. · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to investigate neuronal-glial cell signaling in trigeminal ganglia under basal and inflammatory conditions using an in vivo model of trigeminal nerve activation.
Activation of trigeminal ganglion nerves and release of calcitonin gene-related peptide (CGRP) are implicated in the pathology of migraine. Cell bodies of trigeminal neurons reside in the ganglion in close association with glial cells. Neuron-glia interactions are involved in all stages of inflammation and pain associated with several central nervous system (CNS) diseases. However, the role of neuron-glia interactions within the trigeminal ganglion under normal and inflammatory conditions is not known.
Sprague-Dawley rats were utilized to study neuron-glia signaling in the trigeminal ganglion. Initially, True Blue was used as a retrograde tracer to localize neuronal cell bodies in the ganglion by fluorescent microscopy and multiple image alignment. Dye-coupling studies were conducted under basal conditions and in response to capsaicin injection into the TMJ capsule. S100B and p38 expression in neurons and glia were determined by immunohistochemistry following chemical stimulation. CGRP levels in the ganglion were measured by radioimmunoassay in response to capsaicin. In addition, the effect of CGRP on the release of 19 different cytokines from cultured glial cells was investigated by protein microarray analysis.
In unstimulated control animals, True Blue was detected primarily in neuronal cell bodies localized in clusters within the ganglion corresponding to the V3 region (TMJ capsule), V2 region (whisker pad), or V1 region (eyebrow and eye). However, True Blue was detected in both neuronal cell bodies and adjacent glia in the V3 region of the ganglion obtained from animals injected with capsaicin. Dye movement into the surrounding glia correlated with the time after capsaicin injection. Chemical stimulation of V3 trigeminal nerves was found to increase the expression of the inflammatory proteins S100B and p38 in both neurons and glia within the V3 region. Unexpectedly, increased levels of these proteins were also observed in the V2 and V1 regions of the ganglion. CGRP and the vesicle docking protein SNAP-25 were colocalized in many neuronal cell bodies and processes. Decreased CGRP levels in the ganglion were observed 2 hours following capsaicin stimulation. Using protein microarray analysis, CGRP was shown to differentially regulate cytokine secretion from cultured trigeminal ganglion glia.
We demonstrated that activation of trigeminal neurons leads to changes in adjacent glia that involve communication through gap junctions and paracrine signaling. This is the first evidence, to our knowledge, of neuron-glia signaling via gap junctions within the trigeminal ganglion. Based on our findings, it is likely that neuronal-glial communication via gap junctions and paracrine signaling are involved in the development of peripheral sensitization within the trigeminal ganglion and, thus, are likely to play an important role in the initiation of migraine. Furthermore, we propose that propagation of inflammatory signals within the ganglion may help to explain commonly reported symptoms of comorbid conditions associated with migraine.
Headache The Journal of Head and Face Pain 01/2007; 47(7):1008-23; discussion 24-5. · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The current state of art of detoxifying collective protection structures and shelters used by the Army is tedious, cumbersome and importantly lacks fast response to chem. and biol. attack. We have designed smart polymeric coatings that can be applied on structures, which respond instantly by destroying chem. and biol. warfare agents (CBA) on contact. Our smart polymeric coatings are capable of generating hydrogen peroxide in-situ, which subsequently gets activated by a catalytic coating to an aggressive oxidative state that destroys CBA. We report the development of an integrated polymeric system that generates hydrogen peroxide and activated peroxide in-situ. The oxidn./hydrolysis of chem. and biol. agent surrogates using activated peroxides will also be presented. [on SciFinder(R)]
234th ACS National Meeting, Boston, MA, United States; 01/2007