In this thesis, the innervation patterns by substance P- (SP), dopamine-beta-hydroxylase- (DbetaH) and the vesicular acetylcholine transporter- (VAChT) immunoreactive (IR) fibres were investigated in the skin of the rat lower lip, in order to provide a morphological basis for the possible interactions between sensory and autonomic fibres in the periphery. Our immunocytochemical approach revealed that SP-IR sensory fibres were widely distributed throughout the epidermis and dermis. In the dermis, they were associated with blood vessels, hair follicles, sebaceous glands and mast cells. Electron microscopical quantification revealed that SP-IR fibres equally innervated arterioles, capillaries and venules, all of which were shown to possess SP receptor (NK-1r) immunoreactivity within their walls. DbetaH- and VAChT-IR fibres were present around blood vessels in the lower dermis, but not in the upper dermis, indicating that these fibres are not as widely distributed as the SP-IR fibres. SP-DbetaH, SP-VAChT and DbetaH-VAChT fibre combinations were observed around lower dermal blood vessels. The absence of single labeled blood vessels suggested that blood vessels in the lower dermis are innervated by all three fibre-types. Quantification at the ultrastructural level revealed that DbetaH- and VAChT-IR terminals lie closer to their targets than SP-IR terminals. Bilateral lesions of the mental nerve, a purely sensory nerve, led to the total loss of SP-IR fibres from the lower lip skin, and to the migration of DbetaH-IR fibres into the upper dermis, a territory from which they are normally absent. These sprouted fibres remained in their new territory despite the reinnervation of the lower lip by SP-IR fibres. The bilateral removal of the superior cervical ganglia (SCG) caused the complete degeneration of DbetaH-IR fibres and a transient SP-IR fibre sprouting and NK-1r up-regulation. The number of SP-IR fibres and the content of SP within these fibres was increased both in th / Therefore we can conclude that SP-, DbetaH- and VAChT-IR fibres all innervate the same blood vessels in the lower dermis of the rat lower lip skin. Furthermore, the plastic changes observed in the association between SP- and DbetaH-IR fibres following trauma to peripheral nerve injuries, may lead to painful sensations and, possibly, abnormal blood flow in the affected region.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.38091 |
| Date | January 2001 |
| Creators | Ruocco, Isabella. |
| Contributors | Ribeiro-da-Silva, Alfredo (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Pharmacology & Therapeutics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001837478, proquestno: NQ75675, Theses scanned by UMI/ProQuest. |
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