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Glibenclamide decelerates the responses of coronary regulation in the goat
Ist Teil von
American journal of physiology. Heart and circulatory physiology, 1994-05, Vol.266 (5), p.H1715-H1721
Ort / Verlag
United States
Erscheinungsjahr
1994
Quelle
MEDLINE
Beschreibungen/Notizen
J. Dankelman, C. P. Van der Ploeg and J. A. Spaan
Department of Medical Physics and Informatics, University of Amsterdam, The Netherlands.
The role of blocking ATP-sensitive potassium (KATP) channels by
glibenclamide on the dynamic responses of coronary resistance to abrupt
changes in perfusion pressure and heart rate was investigated. The left
main coronary artery of the open-chest anesthetized goat was perfused with
constant pressure (Pp). Pp and arterial flow were averaged per beat, and
their ratio was calculated as index of coronary resistance. Responses of
resistance index after heart rate (HR) and Pp changes before and after
administration of glibenclamide were compared. Their rate of change was
quantified by t50, the required time to obtain half of the complete
response. During control, t50 for the dilating response induced by a
decrease in Pp or increase in HR was 3.8 +/- 0.2 and 6.2 +/- 0.5 (SE) s,
respectively. With glibenclamide these values were 24.4 +/- 1.6 and 14.9
+/- 2.1 s. For the constricting response, the numbers for control were 5.8
+/- 0.3 (increase Pp) and 7.2 +/- 0.8 (decrease HR) s. With glibenclamide
these values were 22.1 +/- 1.5 and 16.0 +/- 2.9 s. The steady-state
adjustment of coronary flow was not altered by glibenclamide. It was
concluded that glibenclamide has a minor effect on coronary flow control
but reduces the rate of change of coronary resistance index up to a factor
of four. Because glibenclamide is supposed to act on KATP channels, it may
be concluded that these channels play a major role in the dynamics of
coronary blood flow regulation.