Transcranial Doppler in spontaneous attacks of migraine

Neurovascular Compression-Induced Intracranial Allodynia May Be the True Nature of Migraine Headache: an Interpretative Review

PURPOSE OF REVIEW

Surgical deactivation of migraine trigger sites by extracranial neurovascular decompression has produced encouraging results and challenged previous understanding of primary headaches. However, there is a lack of in-depth discussions on the pathophysiological basis of migraine surgery. This narrative review provides interpretation of relevant literature from the perspective of compressive neuropathic etiology, pathogenesis, and pathophysiology of migraine.

RECENT FINDINGS

Vasodilation, which can be asymptomatic in healthy subjects, may produce compression of cranial nerves in migraineurs at both extracranial and intracranial entrapment-prone sites. This may be predetermined by inherited and acquired anatomical factors and may include double crush-type lesions. Neurovascular compression can lead to sensitization of the trigeminal pathways and resultant cephalic hypersensitivity. While descending (central) trigeminal activation is possible, symptomatic intracranial sensitization can probably only occur in subjects who develop neurovascular entrapment of cranial nerves, which can explain why migraine does not invariably afflict everyone. Nerve compression-induced focal neuroinflammation and sensitization of any cranial nerve may neurogenically spread to other cranial nerves, which can explain the clinical complexity of migraine. Trigger dose-dependent alternating intensity of sensitization and its synchrony with cyclic central neural activities, including asymmetric nasal vasomotor oscillations, may explain the laterality and phasic nature of migraine pain. Intracranial allodynia, i.e., pain sensation upon non-painful stimulation, may better explain migraine pain than merely nociceptive mechanisms, because migraine cannot be associated with considerable intracranial structural changes and consequent painful stimuli. Understanding migraine as an intracranial allodynia could stimulate research aimed at elucidating the possible neuropathic compressive etiology of migraine and other primary headaches.

Magnesium as an Important Factor in the Pathogenesis and Treatment of Migraine—From Theory to Practice

So far, no coherent and convincing theory has been developed to fully explain the pathogenesis of migraine, although many researchers and experts emphasize its association with spreading cortical depression, oxidative stress, vascular changes, nervous excitement, neurotransmitter release, and electrolyte disturbances. The contribution of magnesium deficiency to the induction of cortical depression or abnormal glutamatergic neurotransmission is a likely mechanism of the magnesium–migraine relationship. Hence, there is interest in various methods of assessing magnesium ion deficiency and attempts to study the relationship of its intra- and extracellular levels with the induction of migraine attacks. At the same time, many clinicians believe that magnesium supplementation in the right dose and form can be a treatment to prevent migraine attacks, especially in those patients who have identified contraindications to standard medications or their different preferences. However, there are no reliable publications confirming the role of magnesium deficiency in the diet as a factor causing migraine attacks. It also seems interesting to deepen the research on the administration of high doses of magnesium intravenously during migraine attacks. The aim of the study was to discuss the probable mechanisms of correlation of magnesium deficiency with migraine, as well as to present the current clinical proposals for the use of various magnesium preparations in complementary or substitute pharmacotherapy of migraine. The summary of the results of research and clinical observations to date gives hope of finding a trigger for migraine attacks (especially migraine with aura), which may turn out to be easy to diagnose and eliminate with pharmacological and dietary supplementation.

Migraine and Its Association with Hyperactivity of Cell Membranes in the Course of Latent Magnesium Deficiency-Preliminary Study of the Importance of the Latent Tetany Presence in the Migraine Pathogenesis

So far, there is no consistent and convincing theory explaining the pathogenesis of migraines. Vascular disorders, the effect of oxidative stress on neurons, and the contribution of magnesium-calcium deficiencies in triggering cortical depression and abnormal glutaminergic neurotransmission are taken into account. However, there are no reliable publications confirming the role of dietary deficits of magnesium and latent tetany as factors triggering migraine attacks. The aim of the study was to evaluate the influence of latent magnesium deficiency assessed with the electrophysiological tetany test on the course of migraine. The study included: a group of 35 patients (29 women and six men; in mean age 41 years) with migraine and a control group of 24 (17 women and seven men; in mean age 39 years) healthy volunteers. Migraine diagnosis was based on the International Headache Society criteria, 3rd edition. All patients and controls after full general and neurological examination were subjected to a standard electrophysiological ischemic tetany test. Moreover, the level of magnesium in blood serum was tested and was in the normal range in all patients. Then, the incidence of a positive tetany EMG test results in the migraine group and the results in the subgroups with and without aura were compared to the results in the control group. Moreover, the relationship between clinical markers of spasmophilia and the results of the tetany test was investigated in the migraine group. As well as the relationship between migraine frequency and tetany test results. There was no statistically significant difference in the occurrence of the electrophysiological exponent of spasmophilia between the migraine and control group. Neither correlation between the occurrence of clinical symptoms nor the frequency of migraine attacks and the results of the tetany test was stated (p > 0.05). However, there was an apparent statistical difference between the subgroup of migraine patients with aura in relation to the control group (p < 0.05). The result raises hope to find a trigger for migraine attacks of this clinical form, the more that this factor may turn out to be easy to supplement with dietary supplementation.

Effect of occipitoatlantal decompression on cerebral blood flow dynamics as evaluated by Doppler ultrasonography

Context

Osteopathic manipulative treatment reduces symptoms in patients with headache disorders, but the underlying mechanisms are unclear.

Objective

To evaluate blood flow in the intracranial and extracranial vasculature before and after occipitoatlantal decompression (OAD) using Doppler ultrasonography.

Methods

Healthy, first-year osteopathic medical students from A.T. Still University's Kirksville College of Osteopathic Medicine participated in a randomized, single-blinded, two-period, two-treatment crossover study. The participants were randomly assigned to 1 of 2 treatment interventions: OAD or sham touch. After one week, participants returned to have the other intervention performed. Blood flow parameters-peak systolic velocity (PSV) and end-diastolic velocity (EDV)-in the middle cerebral artery (MCA), internal carotid artery (ICA), and vertebral artery (VA) were evaluated before, immediately after, 5 minutes after, and 10 minutes after treatment. Differences in PSV, EDV, heart rate (HR), and blood pressure (BP) for both interventions were analyzed for the four time points using mixed-effects models.

Results

Thirty healthy medical students (11 men, 19 women; mean age, 24 years) participated in this study. EDV increased after OAD in the MCA, ICA, and VA (all p<0.001); no change occurred after sham touch (all p>0.05). EDV was greater for all post-treatment timepoints after OAD in the MCA, ICA, and VA than after sham touch (all p<0.001). Although baseline PSV in the MCA measured before treatment was different between treatment interventions (p=0.01), no difference was found between interventions at any post-treatment time point (all p>0.59). Changes in PSV in the ICA and VA and for HR and BP did not depend on treatment intervention (p>0.06).

Conclusion

Increases in EDV occurred in major cranial arteries after OAD but not after sham touch, indicating that OAD improves blood flow to the brain. The exact mechanism of this increase is unknown; however, it can be explained by either parasympathetic stimulation through the secretion of vasodilating neurotransmitters or by a decrease in external tissue pressure on ICA and VA, with the resulting flow causing further dilation in the MCA.

Cerebral hemodynamics in the different phases of migraine and cluster headache

Headache is one of the most common ailments; migraine is one of the most prevalent and disabling neurological disorders and cluster headache presents as one of the most excruciating pain disorders. Both are complex disorder characterized by recurrent episodes of headache. A key feature is that various triggers can set off an attack providing the opportunity to explore disease mechanisms by experimentally inducing attacks. This review summarizes neuroimaging and hemodynamic studies in human in provoked and spontaneous attacks of migraine and cluster headache. Cerebral hemodynamics during different phases of the migraine attack demonstrate alterations in cerebral blood flow and perfusion, vessel caliber, cortical and sub-cortical function, underscoring that migraine pathophysiology is highly complex. Migraine attacks might begin in diencephalic and brainstem areas, whereas migraine aura is a cortical phenomenon. In cluster headache pathophysiology, the hypothalamus might also play a pivotal role, whereas the pattern of cerebral blood flood differs from migraine. For both disorders, alterations of arterial blood vessel diameter might be more an epiphenomenon of the attack than a causative trigger. Studying cerebral hemodynamics in provocation models are important in the search for specific biomarkers in the hope to discover future targets for more specific and effective mechanism-based anti-headache treatment.

White matter hyperintensities in migraine: Clinical significance and central pulsatile hemodynamic correlates

Background The role of central pulsatile hemodynamics in the pathogenesis of white matter hyperintensities in migraine patients has not been clarified. Methods Sixty patients with migraine (20-50 years old; women, 68%) without overt vascular risk factors and 30 demographically-matched healthy controls were recruited prospectively. Cerebral white matter hyperintensities volume was determined by T1-weighted magnetic resonance imaging with CUBE-fluid-attenuated-inversion-recovery sequences. Central systolic blood pressure, carotid-femoral pulse wave velocity, and carotid augmentation index were measured by applanation tonometry. Carotid pulsatility index was derived from Doppler ultrasound carotid artery flow analysis. Results Compared to the controls, the migraine patients had higher white matter hyperintensities frequency (odds ratio, 2.75; p = 0.04) and greater mean white matter hyperintensities volume (0.174 vs. 0.049, cm³, p = 0.04). Multivariable regression analysis showed that white matter hyperintensities volume in migraine patients was positively associated with central systolic blood pressure ( p = 0.04) and carotid-femoral pulse wave velocity ( p < 0.001), but negatively associated with carotid pulsatility index ( p = 0.04) after controlling for potential confounding factors. The interaction effects observed indicated that the influence of carotid-femoral pulse wave velocity ( p = 0.004) and central systolic blood pressure ( p = 0.03) on white matter hyperintensities formation was greater for the lower-carotid pulsatility index subgroup of migraine patients. White matter hyperintensities volume in migraine patients increased with decreasing carotid pulsatility index and with increasing central systolic blood pressure or carotid-femoral pulse wave velocity. Conclusions White matter hyperintensities are more common in patients with migraine than in healthy controls. Increased aortic stiffness or central systolic blood pressure in the presence of low intracranial artery resistance may predispose patients with migraine to white matter hyperintensities formation.

Longitudinal changes in cerebral blood flow velocities in different clinical courses of migraine

Objective To assess longitudinal changes in cerebral blood flow velocities (ΔCBFVs) according to the clinical course of migraine. Methods We retrospectively included migraine patients with two or more attacks per month at baseline who were followed up within 2 years with transcranial Doppler in a tertiary headache clinic. ΔCBFVs were analyzed in relation to clinical courses, defined as remission (0-1 headache days/month), persistence (2-14/month), or progression (≥15/month) in episodic migraine (EM), and conversion to EM (<15/month) and persistence (≥15/month) in chronic migraine (CM). Results A total of 166 patients (90 EM and 76 CM) were included. In EM, the remission group ( n = 30) showed a decrease in CBFV in the middle cerebral artery (MCA) and the basilar artery (BA). The progression group ( n = 10) showed increasing CBFVs in the bilateral MCAs. Patients with the persistence course ( n = 50) showed generally unchanged CBFVs. In CM, ΔCBFVs decreased in the BA and increased in the posterior cerebral artery (PCA) after conversion to EM ( n = 61), whereas they remained unchanged in the persistence group ( n = 15). In all patients, % change in headache days was positively correlated with the %ΔCBFVs of the bilateral MCAs and the BA. Conclusions CBFV changes are associated with the different clinical courses of migraine. The association is more prominent in EM than CM.

“Prolonged” migraine aura: New information on underlying mechanisms

The aim of this study is to identify the pathophysiology of “prolonged” migraine aura not clearly understood. We studied cortical cerebral microcirculation by Near Infrared Spectroscopy system (NIRS) and cerebral macrocirculation by transcranial Doppler (TCD) in 8 subjects (3 M and 5 F, age range 21–41 years) during spontaneous “prolonged” migraine aura in according to ICHD-II criteria 2004 (code 1.6.2.) up to 24 hours after the end of aura and compared the results with the headache-free periods. During aura NIRS showed a significant decrease of the Arterial Pulse Wave of Cerebral Microcirculation (APWCM) amplitude (−33 % ± 5.7), p<0.001, and a significant increase of Cerebral Tissue Oxygen Saturation (SctO2) (+15.5 % ± 5.1), p<0.001 contralateral to the symptoms of aura compared with the headache-free periods; TCD showed a significant increase of Pulsatility Index (+36.5 % ± 6.5), p<0.001 and a significant decrease of the diastolic velocity in the posterior and middle cerebral artery contralateral to the symptoms of aura compared with the headache-free periods. In conclusion during “prolonged” migraine aura we find areas of cortical hypoperfusion corresponding to the topography of aura symptoms that are the result of a decreased metabolic demand rather than an ischemic mechanism.

Transcranial Doppler measurements in migraine and nitroglycerin headache

The objective of this study was to examine the cerebral circulation during spontaneous migraine attacks and to compare changes to an experimental headache model induced by nitroglycerin (NTG) infusion. This prospective study was carried out in a tertiary care hospital on migraineurs with or without aura. Healthy volunteers served as controls. There were no interventions. Flow velocity (FV) and pulsatility index (PI) were measured in migraineurs between and during headache attacks. In controls, FV and PI of the middle cerebral arteries were performed at baseline and after each IV infusion of 0.125, 0.25 and 0.5 microg/kg/min of NTG. In migraineurs, a significant increase in the mean flow velocity (MFV) in the left vertebral artery (VA) and the PI of the right VA during spontaneous migraine headache was found. In controls, all FV significantly decreased after infusion of NTG. The NTG model produces expected and substantially different vascular effects than those seen with spontaneous migraine headache.

Increased dilator response to nitrate and decreased flow-mediated dilatation in migraineurs

BACKGROUND

It has been known that in a migraine attack intracranial and extracranial arteries on the headache side dilate and when the migraine attack has subsided, the intracranial arteries show segmental narrowing. We hypothesized that patients with migraine had an underlying systemic vasomotion abnormality and there might be an increased nitrate-mediated vasodilatory response in the brachial artery of migraineurs. Accordingly we aimed to measure endothelium dependent and independent functions of brachial artery in migraineurs and healthy subjects.

MATERIALS AND METHODS

Twenty-four patients who fulfilled the diagnostic criteria of migraine were enrolled in the study. Twenty-six age- and sex-matched healthy control subjects comprised the control group. Flow-mediated dilatation and nitrate-mediated dilatation were measured in all patients and control subjects by means of brachial artery ultrasonography.

RESULTS

Flow-mediated dilatation of patients with migraine was significantly lower than that of control subjects (7.6 +/- 3.7% vs 10.4 +/- 3.5%, respectively, P= .008). However, nitrate-mediated dilatation in migraineurs was significantly higher than that of nonmigraineurs (25% vs 14%, respectively, P< .001).

CONCLUSION

We have shown that migraineurs have decreased endothelium dependent function whereas increased nitrate-mediated response in their brachial artery. It can be suggested that the mechanism underlying migraine may be a diffuse vascular vasomotion abnormalities and migraine may be a local manifestation of systemic vascular abnormality rather than a primary cerebral phenomenon.

Color Doppler sonography of orbital and vertebral arteries in migraineurs without aura

PURPOSE

The objective of this study was to investigate whether the retrobulbar hemodynamics in the ophthalmic (OA), posterior ciliary (PCA), central retinal (CRA), and vertebral (VA) arteries are affected in migraineurs without aura.

METHODS

The eyes of migraineurs without aura and those of healthy control subjects were evaluated during both headache and headache-free periods. Retrobulbar and vertebral blood flow velocities in the OA, PCA, CRA, and the extracranial part of the VA were measured bilaterally using color Doppler sonography. The peak systolic and end-diastolic flow velocities and the pulsatility (PI) and resistance (RI) indices were determined for all arteries.

RESULTS

In total, we enrolled 30 migraineurs and 31 healthy control subjects. Statistically significant differences between headache-free migraineurs and control subjects were observed in the PI and RI of both right and left PCAs and in the RI of both right and left CRAs. The PI and RI of the left VA of the migraineurs were significantly lower during both headache and headache-free periods than were those of the control subjects. Among the migraineurs, the peak systolic and end-diastolic velocities of the left VA were increased during headache periods relative to those found during the headache-free periods.

CONCLUSIONS

The retrobulbar circulation and flow hemodynamics in the left VA may be altered in both headache and headache-free periods in migraineurs without aura. The differences found between migraineurs and control subjects may implicate autonomic dysfunction in migraineurs.

Biofeedback-assisted relaxation in migraine headache: relationship to cerebral blood flow velocity in the middle cerebral artery

OBJECTIVE

To determine if migraineurs with aura respond differently to biofeedback/relaxation than those without aura and, if so, whether the variability in outcome can be explained by blood flow velocity. Background.-The relationship between cerebral blood flow velocity and treatment response to biofeedback/relaxation in migraine with and without aura is uncertain.

METHOD

Twenty migraineurs underwent 12 sessions of biofeedback/relaxation therapy, while 20 controls simply were told to relax on their own. Cerebral blood flow velocity was measured bilaterally in the middle cerebral artery with transcranial Doppler.

RESULTS

The biofeedback group showed significant (P <.05) reductions in pain, depression, and anxiety compared to the control group. Patients with and without aura did equally well. There were significant (P <.05) left to right blood flow velocity differences only in the migraine with aura group. Maximum blood flow velocities were significantly higher (P <.05) in the migraine with aura group than in the cohort without aura. There was an inverse correlation between indicators of anxiety and blood flow velocity, perhaps related to hyperventilation-induced constriction in the small vessels distal to the middle cerebral artery.

CONCLUSION

The positive treatment response to biofeedback/relaxation in migraine headache is not related to presence of aura, nor to changes in blood flow velocity, but may be associated with reduction in anxiety and depression.

Blood flow velocity and pulsatility index differences in patients with unilateral migraine

OBJECTIVE

To evaluate blood flow velocity and pulsatility in unilateral migraine without aura during the headache-free period using transcranial Doppler (TCD) sonography.

METHODS

Patients with unilateral headache were recruited during the headache-free period. Maximum mean flow velocity (MFV) and pulsatility index (PI) were measured in the middle cerebral (MCA) and basilar arteries. Controls were headache-free individuals without cerebrovascular disease.

RESULTS

Twenty-five patients with right-sided migraine, 25 patients with left-sided migraine, and 19 controls were studied. The MCA PI was higher on the right headache side versus the left headache side (0.97 +/- 0.2 versus 0.86 +/- 0.1 cm/s, P =.02) and versus controls (0.9 +/- 0.2 cm/s, NS). The basilar artery MFV was higher in patients with right-sided headache versus left-sided headache (39.5 +/- 5.6 versus 34.7 +/- 8.2 cm/s, P =.02) and versus controls (38.2 +/- 8 cm/s, NS). No decrease in MFV with age was observed in patients with migraine.

CONCLUSIONS

Middle cerebral artery flow pulsatility and basilar artery velocity are higher in patients with right-sided migraine compared with left-sided migraineurs, during the headache-free period. Although these parameters were similar to controls, the differences found during the headache-free period in migraineurs may indicate vascular involvement predisposing to the unilateral headache recurrence.

Transcranial Doppler ultrasonography: year 2000 update

In this update, the main clinical applications of transcranial Doppler ultrasonography are reassessed. A specific format for technology assessment, personal experience, and an extensive review of the literature form the basis of the evaluation. The document is approved by the American Society of Neuroimaging and the Neurosonology Research Group of the World Federation of Neurology.

Investigations into the role of nitric oxide and the large intracranial arteries in migraine headache

Previous studies suggest that nitric oxide (NO) is involved in headaches induced by i.v. infusion of the vasodilator and NO donor glyceryl trinitrate (GTN) in healthy subjects. Extending these studies to sufferers of migraine without aura, it was found that migraineurs experienced a stronger headache than non-migraineurs. In addition, most migraineurs experienced a delayed migraine attack at variable times (mean 5.5 h) after GTN provocation. This biphasic headache response in migraineurs may be linked to hypersensitivity in the NO-cGMP pathway. Thus, compared to controls, migraineurs were found to be more sensitive to GTN-induced intracranial arterial dilatation, which is known to be mediated via liberation of NO and subsequent synthesis of cGMP Furthermore, histamine infusions in migraineurs induced headache responses and intracranial arterial responses resembling those induced by GTN in migraineurs. Histamine is known to liberate NO from the endothelium via stimulation of the H1 receptor, which is present in the large intracranial arteries in man. Because both immediate histamine-induced headache and intracranial arterial dilatation and delayed histamine-induced migraine are blocked by H1-receptor blockade, a likely common pathway for GTN and histamine-induced headaches/migraines and intracranial arterial responses may be via activation of the NO-cGMP pathway. The delay in the development of these experimental migraines may reflect activation of multiple physiological processes. The intracranial arteries of migraineurs were found supersensitive to the vasodilating effect of GTN (exogenous NO). This relates to clinical findings suggesting dilatation of the large intracranial arteries on the headache side during spontaneous migraine attacks. The function of arterial regulatory mechanisms involving NO in migraine was therefore studied. In peripheral arteries, no endothelial dysfunction of NO was found and cardiovascular and intracranial arterial sympathetic function was normal. A mild parasympathetic dysfunction may be involved and may, via denervation supersensitivity, be responsible for the observed supersensitivity to NO. Another possibility is that NO initiates a perivascular neurogenic inflammation with liberation of vasoactive peptides. NO also mediates a variety of other physiological phenomena. One of these, the pain-modulating effect observed in animals, was evaluated in a human study using GTN infusion and measurements of pain thresholds. No definite effects of GTN were demonstrated. The precise mechanisms involved in NO-triggered migraines and which part of the NO-activated cascade that is involved remain to be determined. The possibilities for pharmacological stimulation and/or inhibition of several steps of the NO-activated cascade increase rapidly and soon may be available for human studies.

Influence of caffeine and caffeine withdrawal on headache and cerebral blood flow velocities

Caffeine consumption may cause headache, particularly migraine. Its withdrawal also produces headaches and may be related to weekend migraine attacks. Transcranial Doppler sonography (TCD) has shown changes in cerebral blood flow velocities (BFV) during and between attacks of migraine. In order to examine whether headache and changes in BFV could develop from controlled caffeine alterations, 20 healthy volunteers without a headache history, underwent clinical evaluation, TCD and serum caffeine measurements on four occasions, comparing conditions of regular caffeine intake, caffeine withdrawal and "re-caffeination". After 24 h of complete caffeine abstinence, 10 suffered from moderate to severe headaches with complete recovery within 1 h after caffeine intake. The BFVs in both middle cerebral, both posterior cerebral and basilar arteries were higher following the withdrawal period, reaching statistical significance in the left middle cerebral basilar and both posterior cerebral arteries. BFVs decreased significantly within half an hour after caffeine intake in all subjects, and were similar to baseline values after 2 h. Our results emphasize the relationship between caffeine withdrawal, the development of headache and alterations in cerebral blood flow velocities. Also, these findings indicate that accurate interpretation of TCD measurements should account for the influence of caffeine on BFVs.

Cerebral blood flow velocities are reduced during attacks of unilateral migraine without aura

It has been disputed whether or not large intracranial arteries are dilated during migraine attacks. In order to answer this question the present transcranial Doppler study focused on side-to-side differences of middle cerebral artery blood velocity during unilateral attacks of migraine without aura in 25 patients. Blood velocity in the middle cerebral artery was lower on the headache side (59 cm/s) than on the non-headache side (65 cm/s) during the migraine attack. No such difference was found outside of attack (65 cm/s both sides). The difference (headache side minus non-headache side) was on average -6.1 cm/s during attack compared to -0.4 cm/s outside of attack (p = 0.01). Assuming that rCBF is unchanged during attacks of migraine without aura, our results suggest a 9% increase in middle cerebral artery lumen (cross-sectional area) on the affected side during unilateral attacks of migraine without aura. The findings, however, do not necessarily mean that arterial dilatation is the only or even the most significant cause of pain.

Suppression by the sumatriptan analogue, CP-122,288 of c-fos immunoreactivity in trigeminal nucleus caudalis induced by intracisternal capsaicin

1. The effects of an intravenously administered sumatriptan analogue were examined on c-fos-like immunoreactivity (c-fos-LI), a marker of neuronal activation, evoked within trigeminal nucleus caudalis (TNC) and other brain stem regions 2 h after intracisternal injection of the irritant, capsaicin (0.1 ml, 0.1 mM), in pentobarbitone-anaesthetized Hartley guinea-pigs. 2. C-fos-LI was assessed in eighteen serial sections (50 microns) using a polyclonal antiserum. A weighted average, reflecting total expression within lamina I, IIo of TNC was obtained from three representative levels (i.e., at -0.225 mm, -2.475 mm and -6.975 mm.). 3. Capsaicin caused significant labelling within lamina I, IIo, a region containing axonal terminations of small unmyelinated C-fibres, as well as within the nucleus of the solitary tract, area postrema and medial reticular nucleus. A similar distribution of positive cells was reported previously after intracisternal injection of other chemical irritants such as autologous blood or carrageenin. 4. Pretreatment with a conformationally restricted sumatriptan analogue (with some selectivity for 5-HT1B and 5-HTID receptor subtypes) CP-122,288, reduced the weighted average by approximately 50-60% (P < 0.05) in lamina I, IIo at > or = 100 pmol kg-1, i.v., but did not decrease cell number within area postrema, nucleus of the solitary tract or medial reticular nucleus. A similar pattern was reported previously following sumatriptan, dihydroergotamine or CP-93,129 administration after noxious meningeal stimulation. 5. We conclude that modifications at the amino-ethyl side chain of sumatriptan dramatically enhance the suppression of c-fos expression within TNC, a finding consistent with its remarkable potency against neurogenic plasma protein extravasation within dura mater. CP-122,288 and related analogues may serve as an important prototype for drug development in migraine and related headaches.

Endothelin 1 in migraine and tension-type headache

We determined the plasma levels of ET1, both interictally and ictally, in 50 migraine patients, 20 with aura (MPA) and 30 without aura (MPWA), comparing them with the levels of 40 age-matched tension-type headache patients (20 episodic and 20 chronic) (ETTHP and CTTHP) and the levels of a group of 20 healthy control subjects (CS). No statistically significant difference was evident between the mean ET1 plasma levels of MPA and those of MPWA, assessed in headache-free periods. The mean ET1 plasma levels of MPA and MPWA, assessed interictally, were significantly higher than those of CS. However, the values of plasma ET1 in ETTP and in CTTHP did not differ statistically from those of CS. MPA and MPWA ET1 plasma levels increased significantly within 2 h from the onset of attacks (p < 0.0001) and remained significantly higher between 4 and 6 h from the onset. The ET1 plasma levels of ETTHP and CTTHP assessed during attacks did not differ statistically from those of the same patients assessed in the headache-free periods. The increase in ET1 levels in MPA and MPWA patients when assessed ictally, suggests that this peptide is involved in the haemodynamic changes and vascular tone modifications observed during migraine attacks, particularly in the first phase of the ictal period.