title: Pharmacology of reflex blinks in the rat: a novel model for headache research.
abstract: BACKGROUND
  Migraineurs are highly sensitive to the nitric oxide donor glyceryl trinitrate which triggers attacks in many sufferers. In animal studies, glyceryl trinitrate increases neuronal activity in the trigeminovascular pathway and elevates neurotransmitter levels in the brainstem. Many migraineurs also display alterations in blink reflexes, known to involve brainstem circuits. We investigated the effect of GTN on evoked blinks in the anaesthetised rat to determine whether such reflexes may prove useful as the basis for a novel animal model to evaluate potential anti-migraine therapeutic agents.
  
  
  METHODS
  In anaesthetised rats the electromyogram associated with the reflex blink evoked by corneal airpuff was recorded. Rats were infused with glyceryl trinitrate, sumatriptan plus glyceryl trinitrate or vehicle control. Changes in the magnitude of the reflex blink-associated electromyogram following these treatments were measured.
  
  
  RESULTS
  Glyceryl trinitrate potentiated the evoked reflex blink-associated EMG response from 2 h after infusion. That effect was abolished by simultaneous infusion of sumatriptan with glyceryl trinitrate.
  
  
  CONCLUSIONS
  These results show that simple skin surface measurements of evoked electromyographic activity in the rat can reliably detect the evoked blink reflex that can be potentiated by nitric oxide donors. This novel model may be an effective tool for evaluating putative anti-migraine therapeutic agents.
authors: Neurorestoration Group, Wolfson Centre for Age-Related Disease, Kings College London, London, UK. martyn.jones@kcl.ac.uk.|Zenith NeuroTech, Wolfson Centre for Age-Related Disease, Kings College London, London, UK. martyn.jones@kcl.ac.uk.
authors: M G
authors: MG
authors: Jones
authors: Academic Headache Centre, Wolfson Centre for Age-Related Disease, Kings College London, London, UK.|London and Pain Management and Neuromodulation Centre, St Thomas's Hospital, London, UK.
authors: A P
authors: AP
authors: Andreou
authors: Neurorestoration Group, Wolfson Centre for Age-Related Disease, Kings College London, London, UK.
authors: S B
authors: SB
authors: McMahon
authors: Neurosolutions Ltd., University of Warwick, Coventry, UK.
authors: D
authors: D
authors: Spanswick
mesh_terms: D000818:Animals; D001767:Blinking / Q000187:drug effects*; D004195:Disease Models, Animal; D004576:Electromyography; D008297:Male; D008881:Migraine Disorders / Q000503:physiopathology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects; D058825:Serotonin 5-HT1 Receptor Agonists / Q000494:pharmacology*; D018170:Sumatriptan / Q000494:pharmacology*
chemical_list: D020030:Nitric Oxide Donors; D058825:Serotonin 5-HT1 Receptor Agonists; D018170:Sumatriptan; D005996:Nitroglycerin
keywords: Blink reflex; Migraine; Nitric oxide donor; Sumatriptan