Sumatriptan-Induced Sensitization of the Trigeminal System to Cortical Spreading Depression (CSD) is Blocked by Topiramate

Persistent Link:
http://hdl.handle.net/10150/243092
Title:
Sumatriptan-Induced Sensitization of the Trigeminal System to Cortical Spreading Depression (CSD) is Blocked by Topiramate
Author:
Gu, Pengfei
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release after 31-Jul-2014
Abstract:
The studies in this thesis research were conducted to investigate if sensitivity to induced cortical spread depression (CSD) or the consequence of a CSD event is affected by sumatriptan induced latent sensitization. Previous studies in our lab showed persistent exposure of sumatripan to rats produced a latent state of sensitization. Using persistent sumatripan exposed rats as a model for medication overuse headache, behavior, electrical stimulation threshold to provoke a CSD event and the immunoreactivity of c-Fos in the trigeminal nucleus caudalis (TNC) were characterized. Current results showed no statistical difference of electrically induced CSD thresholds in anesthetized rats measured at day 20 in sumatripan exposed rats compared with saline treated rats. Topiramate (80 mg/kg, i.p.) used clinically for prophylaxis of migraine headache significantly increased CSD threshold in both saline and sumatriptan infused rats. CSD events appear to be associated with trigeminal vascular system activation in TNC because c-Fos expression significantly enhanced in rats with electrically stimulated CSD events. As compared to saline treated rats, sumatriptan-exposed rats demonstrated a significantly higher number of c-Fos positive cells following the electrically stimulated CSD event. Under environmental stress (bright light), sumatripan exposed rats demonstrated decreased response thresholds to periorbital and hindpaw tactile stimuli (i.e., allodynia) and enhanced c-Fos expression in TNC. A single dose of topiramate (80 mg/kg, i.p.) reversed environmental stress induced allodynia and c-Fos over-activity. Taken together, these results suggest that latent sensitization induced by persistent sumatripan exposure seems not correlated to the threshold of electrically stimulated CSD in current model. However, CSD enhanced the responses of trigeminal system in rats with sumatriptan-induced latent sensitization. The protective effects of topiramate shown in this model may be related to blocking the initiation of CSD events resulting from environmental stimulation as well as inhibiting the consequences of CSD events in primary afferents. These findings correlate with clinical observations of protective effects of topiramate for migraine prophylaxis.
Type:
text; Electronic Thesis
Keywords:
Sumatriptan; Topiramate; Medical Pharmacology; Bright light stress; Cortical Spreading Depression
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College; Medical Pharmacology
Degree Grantor:
University of Arizona
Advisor:
Porreca, Frank

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleSumatriptan-Induced Sensitization of the Trigeminal System to Cortical Spreading Depression (CSD) is Blocked by Topiramateen_US
dc.creatorGu, Pengfeien_US
dc.contributor.authorGu, Pengfeien_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseRelease after 31-Jul-2014en_US
dc.description.abstractThe studies in this thesis research were conducted to investigate if sensitivity to induced cortical spread depression (CSD) or the consequence of a CSD event is affected by sumatriptan induced latent sensitization. Previous studies in our lab showed persistent exposure of sumatripan to rats produced a latent state of sensitization. Using persistent sumatripan exposed rats as a model for medication overuse headache, behavior, electrical stimulation threshold to provoke a CSD event and the immunoreactivity of c-Fos in the trigeminal nucleus caudalis (TNC) were characterized. Current results showed no statistical difference of electrically induced CSD thresholds in anesthetized rats measured at day 20 in sumatripan exposed rats compared with saline treated rats. Topiramate (80 mg/kg, i.p.) used clinically for prophylaxis of migraine headache significantly increased CSD threshold in both saline and sumatriptan infused rats. CSD events appear to be associated with trigeminal vascular system activation in TNC because c-Fos expression significantly enhanced in rats with electrically stimulated CSD events. As compared to saline treated rats, sumatriptan-exposed rats demonstrated a significantly higher number of c-Fos positive cells following the electrically stimulated CSD event. Under environmental stress (bright light), sumatripan exposed rats demonstrated decreased response thresholds to periorbital and hindpaw tactile stimuli (i.e., allodynia) and enhanced c-Fos expression in TNC. A single dose of topiramate (80 mg/kg, i.p.) reversed environmental stress induced allodynia and c-Fos over-activity. Taken together, these results suggest that latent sensitization induced by persistent sumatripan exposure seems not correlated to the threshold of electrically stimulated CSD in current model. However, CSD enhanced the responses of trigeminal system in rats with sumatriptan-induced latent sensitization. The protective effects of topiramate shown in this model may be related to blocking the initiation of CSD events resulting from environmental stimulation as well as inhibiting the consequences of CSD events in primary afferents. These findings correlate with clinical observations of protective effects of topiramate for migraine prophylaxis.en_US
dc.typetexten_US
dc.typeElectronic Thesisen_US
dc.subjectSumatriptanen_US
dc.subjectTopiramateen_US
dc.subjectMedical Pharmacologyen_US
dc.subjectBright light stressen_US
dc.subjectCortical Spreading Depressionen_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineMedical Pharmacologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorPorreca, Franken_US
dc.contributor.committeememberOssipov, Michaelen_US
dc.contributor.committeememberDussor, Gregoryen_US
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