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Vasoactivity of the Vasculature Directly Supplying the Rat Sciatic Nerve
Author(s) -
Williams Elise,
Klein Amanda Taylor,
Jackson Dwayne N,
Twynstra Jasna
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.835.4
Subject(s) - sciatic nerve , phenylephrine , sodium nitroprusside , acetylcholine , vasodilation , intravital microscopy , anesthesia , medicine , biomedical engineering , chemistry , blood pressure , microcirculation , nitric oxide
Objectives The purpose of this study was to determine the vasoactivity of the vasculature directly supplying the sciatic nerve in response to phenylephrine (PE) and acetylcholine (ACh) using plasma fluorescence and intravital microscopy. Methods PE (10 −4 M, n=6) and ACh (10 −4 M, n=9) were applied to an exposed sciatic nerve in an anesthetized Sprague Dawley rat model (PE: 321.6±11.7g, ACh: 307.56±41.57g). A fluorescent dye, FITC (0.3 ml at 5%), was infused via a jugular catheter to fluoresce the plasma stream, while intravital microscopy was used to visualize the plasma stream through the vessels running directly over the sciatic nerve. Each vasoactive agent was topically applied over the sciatic nerve for 6 minutes. Measurements were taken at baseline (immediately prior to drug application), 2 minutes, 4 minutes and 6 minutes after the start of drug application, and finally at 4 minutes after PE or ACh application was stopped (recovery). Maximal diameter was achieved via application of 10 −4 M of Sodium Nitroprusside (SNP). Data are expressed as mean ± standard error. Results Following PE and ACh application, mean arterial pressure (baseline PE: 105.6±11.1mmHg; PE: 102.0±9.9mmHg, baseline ACh: 100.8±4.1mmHg, ACh: 100.2±4.6mmHg) was not affected. PE application resulted in a decreased diameter of the plasma stream (maximal change in diameter: −5.8±1.9um), while ACh application did not result in changes in diameter (maximal change in diameter: 1.5±0.7um). Maximal diameter in response to SNP was not significantly different from the baseline diameter (Baseline: 19.36±6.62um, SNP: 19.80±7.01um) Conclusion PE application resulted in a vasoconstriction of the vessels directly supplying the sciatic nerve, while application of ACh or SNP failed to produce significantly vasodilation. Overall, the vessels supplying the sciatic nerve appeared to be maximally dilated at baseline, which may explain the lack of dilation in response to ACh or SNP. Support or Funding Information This study was supported by Brescia University College Research Grant.