Sumatriptan

BackgroundThe development of new anti-migraine treatments is limited by the difficulty inassessing migraine pain in laboratory animals. Depression of activity is one of the few diagnostic criteria formigraine that can be mimicked in rats. The goal of the present study was to test the hypothesis thatdepression of home cage wheel running is a reliable and clinically relevant method to assess migraine painin rats.MethodsAdult female rats were implanted with a cannula to inject allyl isothiocyanate (AITC) onto the dura to induce migraine pain, as has been shown before. Rats recovered from implantation surgery for 8 days in cages containing a running wheel. Home cage wheel running was recorded 23 h a day. AITC and the migraine medication sumatriptan were administered in the hour prior to onset of the dark phase.ResultsAdministration of AITC caused a concentration-dependent decrease in wheel running that lasted 3 h. The duration and magnitude of AITC-induced depression of wheel running was consistent following three repeated injections spaced 48 h apart. Administration of sumatriptan attenuated AITC-induced depressionof wheel running when a large dose (1 mg/kg) was administered immediately following AITC administration. Wheel running patterns did not change when sumatriptan was given to naïve rats.ConclusionsThese data indicate that home cage wheel running is a sensitive, reliable, and clinically relevant method to assess migraine pain in the rat.

BackgroundHeadaches are more frequent in Chronic Fatigue Syndrome (CFS) than healthy control (HC) subjects. The 2004 International Headache Society (IHS) criteria were used to define CFS headache phenotypes.MethodsSubjects in Cohort 1 (HC = 368; CFS = 203) completed questionnaires about many diverse symptoms by giving nominal (yes/no) answers. Cohort 2 (HC = 21; CFS = 67) had more focused evaluations. They scored symptom severities on 0 to 4 anchored ordinal scales, and had structured headache evaluations. All subjects had history and physical examinations; assessments for exclusion criteria; questionnaires about CFS related symptoms (0 to 4 scale), Multidimensional Fatigue Inventory (MFI) and Medical Outcome Survey Short Form 36 (MOS SF-36).ResultsDemographics, trends for the number of diffuse "functional" symptoms present, and severity of CFS case designation criteria symptoms were equivalent between CFS subjects in Cohorts 1 and 2. HC had significantly fewer symptoms, lower MFI and higher SF-36 domain scores than CFS in both cohorts. Migraine headaches were found in 84%, and tension-type headaches in 81% of Cohort 2 CFS. This compared to 5% and 45%, respectively, in HC. The CFS group had migraine without aura (60%; MO; CFS+MO), with aura (24%; CFS+MA), tension headaches only (12%), or no headaches (4%). Co-morbid tension and migraine headaches were found in 67% of CFS. CFS+MA had higher severity scores than CFS+MO for the sum of scores for poor memory, dizziness, balance, and numbness ("Neuro-construct", p = 0.002) and perceived heart rhythm disturbances, palpitations and noncardiac chest pain ("Cardio-construct"; p = 0.045, t-tests after Bonferroni corrections). CFS+MO subjects had lower pressure-induced pain thresholds (2.36 kg [1.95-2.78; 95% C.I.] n = 40) and a higher prevalence of fibromyalgia (47%; 1990 criteria) compared to HC (5.23 kg [3.95-6.52] n = 20; and 0%, respectively). Sumatriptan was beneficial for 13 out of 14 newly diagnosed CFS migraine subjects.ConclusionsCFS subjects had higher prevalences of MO and MA than HC, suggesting that mechanisms of migraine pathogenesis such as central sensitization may contribute to CFS pathophysiology.Clinical trial registrationGeorgetown University IRB # 2006-481

Cortical spreading depression (CSD) in the CNS is suggested as a common mechanism contributing to headache. Despite strong evidence for CNS involvement in headache disorders, drug development for headache disorders remains focused on peripheral targets. Difficulty in delivering drugs across the blood-brain barrier (BBB) may partially account for this disparity. It is known, however, that BBB permeability is increased during several CNS pathologies. In this study, we investigated BBB changes in response to KCl-induced CSD events and subsequent allodynia in rats. Cortical KCl injection in awake, freely moving rats produced facial allodynia with peak intensity between 1.5 and 3 h and CSD induction within 0.5-2 h postinjection. Brain perfusion of 14C-sucrose as a marker of BBB paracellular permeability revealed increased leak in the cortex, but not brainstem, beginning 0.5 h post-KCl injection and resolving within 6 h; no changes in tight junction (TJ) proteins occludin or claudin-5 expression were observed. Acute pretreatment with topiramate to inhibit CSD did not prevent the increased BBB paracellular permeability. CNS delivery of the abortive anti-migraine agent sumatriptan was increased in the cortex 1.5 h post-KCl injection. Surprisingly, sumatriptan uptake was also increased in the brainstem following CSD induction, suggesting regulation of active transport mechanisms at the BBB. Together, these results demonstrate the ability of CSD events to produce transient, time-dependent changes in BBB permeability when allodynia is present and to mediate access of clinically relevant therapeutics (i.e., sumatriptan) to the CNS.

This study examined the solubility of sumatriptan when dissolved in supercritical carbon dioxide. The temperature of the system was varied between 308 and 338 K, and the pressure was ranged between 10 and 30 MPa. The experimental mole fraction and the solubility ranged from 4.30 × 10-6 to 5.26 × 10-5 and from 0.010 to 0.278 g/l respectively with a cross over point of 15 MPa. A total of four semi-empirical models (Chrastil, Bartle et al., K-J, and MST) were evaluated for their potential in facilitating both the correlation and the self-consistency of the data. The K-J method yielded the best outcome, with an AARD of 8.21% and a Radj of 0.991. These models also helped estimate thermal enthalpies ([Formula: see text] = 40.96 kJ mol-1, [Formula: see text] = 59.83 kJ mol-1, and [Formula: see text] = - 18.87 kJ mol-1). Thermodynamic modeling using the PC-SAFT, Peng-Robinson and Soave-Redlich-Kwong combined with mixing rules showed that the PC-SAFT offered better accuracy (AARD = 11.75%, Radj = 0.988). These findings provide essential experimental data and validated predictive models that are critical for designing eco-friendly supercritical fluid processes, such as the supercritical anti-solvent.