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The effect of cortical spreading depression, a proposed initiating event for migraine pain, on cortical blood flow (laser Doppler method) and on the spontaneous firing rate and stimulus-evoked responses of trigemino-cervical neurons with craniovascular input was studied in 17 neurons in 8 cats anesthetized with chloralose. Cortical spreading depression,(More)
A method is described for fabrication of 7-barrelled microiontophoresis electrodes with a center barrel of platinum-coated tungsten. The electrodes require a minimum of expensive apparatus and can be fabricated in an hour or two. The electrodes have low recording impedance (typically 100 k omega and low resistance iontophoresis barrels (typically 20-50 M(More)
Changes in cortical blood flow and cerebrovascular activity occurring during and after cortical spreading depression (CSD) were studied in alpha-chloralose-urethan-anesthetized cats. CSD was induced by superficial cortical pinprick, and laser-Doppler velocimetry (LDV) was used to measure cerebral blood flow (CBFLD). CSD resulted in a wave of cortical(More)
OBJECTIVES To review conjectured modes of action of migraine triggers and to present a new hypothesis about them. BACKGROUND Migraine attacks are initiated in many migraineurs by a variety of "triggers," although in some patients no external trigger can be identified. Many triggers provoke attacks with such a short latency that only some kind of neural(More)
This report examines the effect of the transient receptor potential vanilloid 1 receptor antagonist SB-705498 on neurotransmission and inflammation-induced sensitisation in the trigeminovascular sensory system. A single-neuron electrophysiological animal model for neurovascular head pain was used to evaluate dural and facial noxious inputs and the effects(More)
AIM To use an animal model to test whether migraine pain arises peripherally or centrally. METHODS We monitored the spontaneous and evoked activity of second-order trigeminovascular neurons in rats to test whether traffic increased following a potential migraine trigger (cortical spreading depression, CSD) and by what mechanism any such change was(More)
Electrical stimulation at 1-200/s of the locus coeruleus in 12 Macaca nemestrina monkeys caused a frequency-dependent drop in vascular resistance in the extracerebral circulation which was twice as great on the side stimulated. Accompanying this dilatation of the extracerebral vasculature was a frequency-dependent rise in internal carotid vascular(More)
The effects of ergot alkaloids on field potentials and unit responses produced in the upper cervical spinal cord by stimulation of the superior sagittal sinus (SSS) were examined in 57 anesthetized cats. Electrical stimulation of the SSS produced field potentials and single-unit responses at latencies of 5-20 ms. Field potentials were abolished by section(More)
Cortical spreading depression (SD) has not been shown in the human neocortex by direct cortical recordings. However, animal studies suggest that cortical injury, such as that occurring during neurosurgical procedures, should result in the initiation of SD. It is possible that inhibition of SD by volatile anesthetic agents may partially explain the failure(More)