title: The role of substance P and calcitonin gene-related peptide in neurogenic plasma extravasation and vasodilatation in the rat.
abstract: Immunohistochemistry combined with retrograde tracing has been used to show that of the afferent neurons supplying the dorsomedial surface of the hind paw, approximately 30% contain substance P and 50% calcitonin gene-related peptide immunoreactivity. Stimulation of the saphenous nerve causes plasma extravasation and antidromic vasodilatation in this area of skin. The roles of calcitonin gene-related peptide and substance P released from peripheral afferent endings in mediating these effects were examined using immunoneutralization. In pilot experiments, the binding of radiolabelled peptide to the immunoglobulin fraction of calcitonin gene-related peptide and substance P antisera was characterized in quasi-physiological conditions. Systemic administration of either substance P or calcitonin gene-related peptide antibodies caused a significant decrease (P less than 0.05) in plasma extravasation measured by the Evans Blue method in response to topical application of mustard oil (0.5%) to the skin, or of capsaicin (5 microM) to the saphenous nerve. Topical application of mustard oil also produced a 52.9 +/- 5.1% increase in skin red cell flux. This increase was significantly decreased by both substance P and calcitonin gene-related peptide antibodies. The results suggest that both peptides are involved in mediating neurogenic inflammatory responses.
authors: Department of Physiology, University of Liverpool, U.K.
authors: S M
authors: SM
authors: Louis
authors: A
authors: A
authors: Jamieson
authors: N J
authors: NJ
authors: Russell
authors: G J
authors: GJ
authors: Dockray
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000276:immunology / Q000502:physiology*; D002199:Capillary Permeability / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology; D006614:Hindlimb / Q000294:innervation; D007106:Immune Sera / Q000494:pharmacology; D007249:Inflammation / Q000378:metabolism*; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000276:immunology / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D007106:Immune Sera; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin