In the present study alpha-receptor modulation of coronary flow and cardiac function was examined in exercising dogs, chronically instrumented to measure: circumflex blood flow velocity (CFV), heart rate (HR), global left ventricular function (LVP and dP/dt Max) and regional left ventricular function (%SL and dL/dt (s)max). During exercise, local adrenergic blockade was produced by intracoronary injection of 1.0 mg phentolamine ( anon-specific alpha-antagonist) or .5 mp prazosin. Exercise significantly increased HR, LVP, dP/dt max, CFV, %SL and dL/dt (s)max. Neither alpha-antagonist produced changes in HR, LVP or %SL; however, both phentolamine and prazosin produced significant increses in dP/dtmax, CFV and dL/dt(s)max of the alpha-blocked region, when compared to their exercise level before alpha-blockade. It is suggested that an alpha1-adrenergic vasoconstriction limits coronary vasodilation and, thereby, cardiac function during exercise.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc935562 |
| Date | 12 1900 |
| Creators | Overn, Steven P. (Steven Paul) |
| Contributors | Jones, Carl E., Gwirtz, Patricia A., Barker, David J., Skinner, Charles Gordon |
| Publisher | North Texas State University |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | v, 72 leaves : ill., Text |
| Rights | Public, Overn, Steven P. (Steven Paul), Copyright, Copyright is held by the author, unless otherwise noted. All rights |
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