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Serotonin type 1D receptors (5HT1DR) are differentially distributed in nerve fibres innervating craniofacial tissues

Authors

  • AM Harriott,

    1. Department of Biomedical Sciences and Medical Sciences Training Program, University of Maryland, Baltimore, MD, and Departments of
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  • MS Gold

    Corresponding author
    1. Medicine, Division of Gastroenterology, Hepatology and Nutrition, and
    2. Neurobiology and
    3. the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
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Michael S. Gold, PhD, Department of Medicine, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA W1451, USA. Tel. + 1 412 383 5367, fax + 1 412 383 8663, e-mail goldm@dom.pitt.edu

Abstract

We tested the hypothesis that the 5HT1DR, the primary antinociceptive target of triptans, is differentially distributed in tissues responsible for migraine pain. The density of 5HT1DR was quantified in tissues obtained from adult female rats with Western blot analysis. Receptor location was assessed with immunohistochemistry. The density of 5HT1DR was significantly greater in tissues known to produce migraine-like pain (i.e. circle of Willis and dura) than in structures in which triptans have no antinociceptive efficacy (i.e. temporalis muscle). 5HT1DR-like immunoreactivity was restricted to neuronal fibres, where it colocalized with calcitonin gene-related peptide and tyrosine hydroxylase immunoreactive fibres. These results are consistent with our hypothesis that the limited therapeutic profile of triptans could reflect its differential peripheral distribution and that the antinociceptive efficacy reflects inhibition of neuropeptide release from sensory afferents. An additional site of action at sympathetic efferents is also suggested.

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