title: ATP-sensitive muscle afferents activate spinal trigeminal neurons with meningeal afferent input in rat - pathophysiological implications for tension-type headache.
abstract: BACKGROUND
  Tension-type headache and other primary headaches may be triggered or aggravated by disorders of pericranial muscles, which is possibly due to convergent or collateral afferent input from meningeal and muscular receptive areas. In rodent models high extracellular concentrations of ATP caused muscle nociception and central sensitization of second order neurons. In a rat model of meningeal nociception we asked if spinal trigeminal activity induced by ATP can be modulated by local anaesthesia of distinct muscles.
  
  
  METHODS
  Ongoing activity was recorded from spinal trigeminal neurons with afferent input from the cranial dura mater, the temporal muscle and neck muscles. The stable ATP analogue α,β-methylene adenosine 5'-triphosphate (α,β-meATP, 10 mM) was injected into the ipsilateral temporal muscle, 30 min later followed by injection of local anaesthetics (lidocaine, 2 %) into the ipsilateral neck muscles and/or the temporal muscle.
  
  
  RESULTS
  Injection of α,β-meATP into the temporal muscle caused progressive increase in ongoing activity of most of the spinal trigeminal neurons within 30 min. Injection of lidocaine into the neck muscles and/or the temporal muscle reduced this activation to previous levels within 10 min.
  
  
  CONCLUSIONS
  Distinct spinal trigeminal neurons processing meningeal nociceptive information are under the control of convergent afferent input from several pericranial muscles. Blockade of at least one of these inputs can normalize central trigeminal activity. This may explain why therapeutic manipulations of head muscles can be beneficial in primary headaches.
authors: Institute of Physiology and Pathophysiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Universitätsstr. 17, 91054, Erlangen, Germany.
authors: Moritz
authors: M
authors: Nöbel
authors: Institute of Physiology and Pathophysiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Universitätsstr. 17, 91054, Erlangen, Germany.
authors: Stephan
authors: S
authors: Feistel
authors: Institute of Physiology and Pathophysiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Universitätsstr. 17, 91054, Erlangen, Germany.|Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark.
authors: Jens
authors: J
authors: Ellrich
authors: Institute of Physiology and Pathophysiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Universitätsstr. 17, 91054, Erlangen, Germany. karl.messlinger@fau.de.
authors: Karl
authors: K
authors: Messlinger
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004195:Disease Models, Animal; D004388:Dura Mater / Q000473:pathology* / Q000502:physiology; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology*; D009474:Neurons / Q000502:physiology; D009475:Neurons, Afferent / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D018781:Tension-Type Headache / Q000473:pathology*
chemical_list: D000255:Adenosine Triphosphate; D008012:Lidocaine
keywords: Local anaesthesia; Meningeal nociception; Pericranial muscles; Tension-type headache; α,β-meATP