title: Inefficient constitutive inhibition of P2X3 receptors by brain natriuretic peptide system contributes to sensitization of trigeminal sensory neurons in a genetic mouse model of familial hemiplegic migraine.
abstract: BACKGROUND
  On trigeminal ganglion neurons, pain-sensing P2X3 receptors are constitutively inhibited by brain natriuretic peptide via its natriuretic peptide receptor-A. This inhibition is associated with increased P2X3 serine phosphorylation and receptor redistribution to non-lipid raft membrane compartments. The natriuretic peptide receptor-A antagonist anantin reverses these effects. We studied whether P2X3 inhibition is dysfunctional in a genetic familial hemiplegic migraine type-1 model produced by introduction of the human pathogenic R192Q missense mutation into the mouse CACNA1A gene (knock-in phenotype). This model faithfully replicates several properties of familial hemiplegic migraine type-1, with gain-of-function of CaV2.1 Ca(2+) channels, raised levels of the algogenic peptide calcitonin gene-related peptide, and enhanced activity of P2X3 receptors in trigeminal ganglia.
  
  
  RESULTS
  In knock-in neurons, anantin did not affect P2X3 receptor activity, membrane distribution, or serine phosphorylation level, implying ineffective inhibition by the constitutive brain natriuretic peptide/natriuretic peptide receptor-A pathway. However, expression and functional properties of this pathway remained intact together with its ability to downregulate TRPV1 channels. Reversing the familial hemiplegic migraine type-1 phenotype with the CaV2.1-specific antagonist, ω-agatoxin IVA restored P2X3 activity to wild-type level and enabled the potentiating effects of anantin again. After blocking calcitonin gene-related peptide receptors, P2X3 receptors exhibited wild-type properties and were again potentiated by anantin.
  
  
  CONCLUSIONS
  P2X3 receptors on mouse trigeminal ganglion neurons are subjected to contrasting modulation by inhibitory brain natriuretic peptide and facilitatory calcitonin gene-related peptide that both operate via complex intracellular signaling. In the familial hemiplegic migraine type-1 migraine model, the action of calcitonin gene-related peptide appears to prevail over brain natriuretic peptide, thus suggesting that peripheral inhibition of P2X3 receptors becomes insufficient and contributes to trigeminal pain sensitization.
authors.affiliation: Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Marchenkova
authors.affiliation: Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Vilotti
authors.affiliation: Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy.
authors.forename: Niels
authors.initials: N
authors.lastname: Ntamati
authors.affiliation: Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands.
authors.forename: Arn Mjm
authors.initials: AM
authors.lastname: van den Maagdenberg
authors.affiliation: Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy nistri@sissa.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nistri
mesh_terms: D000818:Animals; D000077221:Calcitonin Gene-Related Peptide Receptor Antagonists; D004195:Disease Models, Animal; D055879:Gene Knock-In Techniques; D051379:Mice; D020325:Migraine with Aura / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D008954:Models, Biological; D020097:Natriuretic Peptide, Brain / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology; D010641:Phenotype; D058920:Purinergic P2X Receptor Antagonists / Q000494:pharmacology; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism; D018015:Receptors, Calcitonin Gene-Related Peptide / Q000378:metabolism; D058477:Receptors, Purinergic P2X3 / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D050916:TRPV Cation Channels / Q000378:metabolism; D012668:Trigeminal Ganglion / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D020867:omega-Agatoxin IVA / Q000494:pharmacology
chemical_list: D000077221:Calcitonin Gene-Related Peptide Receptor Antagonists; D010456:Peptides, Cyclic; D058920:Purinergic P2X Receptor Antagonists; D018015:Receptors, Calcitonin Gene-Related Peptide; D058477:Receptors, Purinergic P2X3; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D020867:omega-Agatoxin IVA; D020097:Natriuretic Peptide, Brain; C068090:anantin; D017461:Receptors, Atrial Natriuretic Factor; C091715:atrial natriuretic factor receptor A
keywords: Trigeminal ganglia; adenosine triphosphate (ATP); calcitonin gene-related peptide; familial hemiplegic migraine type-1; lipid raft; nociception; purinergic receptor