Sympathetic nerve response and vascular function: effects of inflammation on nerve-mediated vasoconstriction in the rat tail artery

Fotso Soh, Jocelyn (2016) Sympathetic nerve response and vascular function: effects of inflammation on nerve-mediated vasoconstriction in the rat tail artery. Masters thesis, Memorial University of Newfoundland.

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Abstract

Chronic inflammation contributes to changes in vascular function in a range of vascular diseases. Whether these vascular changes in function are nerve-mediated remains unknown. Sympathetic nerve-mediated responses in isolated tail arteries of rats in an experimentally induced chronic inflammatory state were examined. Electrical field stimulations between 1.25 and 40 Hz resulted in frequency-dependent contractions sensitive to tetrodotoxin. Neurogenic contractions in blood vessels of experimental animals were significantly greater compared to those of control animals. Alpha₁-adrenoceptor antagonists significantly inhibited contractile responses at lower frequencies of stimulation (1.25 – 5 Hz) in blood vessels of experimental rats compared to controls. Alpha₂-adrenoceptor antagonism had no effect on electric field-evoked vasoconstrictions in experimental and control animals. Inhibition of neuronal reuptake by cocaine comparably enhanced field-stimulated responses in blood vessels of experimental and control animals. Furthermore, the expression of α₁- and α₂-adrenoceptors was different in the endothelium of blood vessels of treated animals compared to control animals. The observation of enhanced neurogenic contraction in blood vessels of animals in a chronic state of inflammation may be attributed to alterations in responsiveness and/or distribution of postjunctional α₁-adrenoceptors.

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