NAME(S): *Kearney, Mark Francis
TITLE(S): Vascular smooth muscle relaxation
induced by glyceryl trinitrate
[microform] : an examination of the role
of thiols and nitric oxide
PUBLISHER: Ottawa : National Library of Canada =
Bibliothèque nationale du Canada, 1997.
DESCRIPTION: 2 microfiches.
SERIES: Canadian theses = Thèses canadiennes
NOTES: Thesis (M.Sc.)--Queen's University at
Kingston, 1996.
Includes bibliographical references.
STUDENT ABSTRACT: The role of thiol-containing compounds
in glyceryl trinitrate (GTN)-induced
vasodilation was investigated using the
thiol-alkylating agent, N-ethylmaleimide
(NEM). Bovine pulmonary artery (BPA)
rings were exposed to increasing doses
of GTN following incubation with NEM.
Incubation decreased maximal relaxation
by 20%. Inhibition of GTN-induced
relaxation was not observed when BPA
rings were treated with
N-acetyl-L-cysteine (NAC) or L-cysteine
prior to incubation with NEM. If
D-cysteine was substituted, a 20%
decrease in tissue response to the
maximal dose of GTN was observed. Nitric
oxide (NO) production from GTN in the
presence of BPA strips was 46 $pm$ 19
pmol NO/g tissue after 10 minutes of
incubation and 76 $pm$ 10 pmol NO/g
after 20 minutes. Following incubation
with NEM, NO was not detected. NO
production from GTN for BPA strips
treated with NAC or L-cysteine before or
after incubation with NEM was elevated
at both time points. An increase was not
observed at either time point for
tissues treated with D-cysteine. NO may
not be the sole metabolite that mediates
GTN-induced vasodilation. The
effectiveness of a novel electrochemical
NO detection technique was tested. A
Clarke-style microelectrode was used to
measure known concentrations of
authentic NO and NO released from SNAP
in a variety of biological media. NO
production from SNAP was first
detectable in saline solution at a
concentration of 0.04 $mu$M SNAP. The
output was 5.9 pA, corresponding to a NO
concentration of 18 nM. In Dulbecco's
solution, the output was 74.6 nM NO. In
Krebs' solution, a sharp and
irreversible decrease in the sensitivity
of the microelectrode was observed. This
detection technique would be useful in
attempting to measure NO from GTN prior
to or concurrently with vascular smooth
muscle relaxation in media that do not
contain high concentrations of CO$sb2$.
(Abstract shortened by UMI.)
NUMBERS: Canadiana: 972134301
ISBN: 0612151530
CLASSIFICATION: 610 20
COPIES: NL Stacks - Mic.F. TJ- 15153
NL Stacks - Mic.F. TJ- 15153 - Copy