Effect of cortical spreading depression on activity of trigeminovascular sensory neurons.
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, induced via cortical pinprick injury, produced an initial wave of cortical hyperemia (243+/-57% of control) and a later and smaller phase of oligemia (96+/-4% of control). Neither the basal discharge rate (6.7+/-1.7 sec(-1)) nor the evoked responses to electrical stimulation of the superior sagittal sinus (4.1+/-0.8 discharges per stimulus) of upper cervical spinal cord neurons was altered over periods of up to 2 h following one, two, or three waves of spreading cortical depression. We conclude that a small number of episodes of cortical spreading depression is not capable of activating C2 cervical spinal cord craniovascular sensory neurons in the cat.
Lambert
G A
GA
Institute of Neurological Sciences, The Prince Henry Hospital, University of New South Wales, Little Bay, Australia. G.Lambert@unsw.edu.au
Michalicek
J
J
Storer
R J
RJ
Zagami
A S
AS
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002415:Cats; D002560:Cerebrovascular Circulation; D013181:Cortical Spreading Depression / Q000502:physiology*; D003392:Cranial Sinuses; D004388:Dura Mater / Q000098:blood supply; D004558:Electric Stimulation; D006439:Hemodynamics; D006940:Hyperemia / Q000209:etiology; D017078:Laser-Doppler Flowmetry; D020325:Migraine with Aura / Q000503:physiopathology; D008959:Models, Neurological; D009475:Neurons, Afferent / Q000502:physiology*; D013116:Spinal Cord / Q000503:physiopathology*; D014276:Trigeminal Nerve / Q000503:physiopathology*; D014793:Visual Cortex / Q000098:blood supply / Q000293:injuries; D014951:Wounds, Stab
D015740:Calcitonin Gene-Related Peptide