| Title: |
Altered coronary and cardiac adrenergic response in the failing hamster heart: role of cyclooxygenase derivatives. |
| Authors: |
Brousseau, Danica, Desjardins, Jean-Francois, Jasmin, Gaetan, Dumont, Louis |
| Source: |
Canadian Journal of Physiology & Pharmacology. Mar2002, Vol. 80 Issue 3, p218. 8p. |
| Subject Terms: |
*HEART physiology, *CYCLOOXYGENASES, *SYMPATHOMIMETIC agents, *INDOMETHACIN, *NONSTEROIDAL anti-inflammatory agents |
| Abstract: |
Although the influence of the adrenergic system has been studied in the presence of heart failure, controver-sies still exist. Since cyclooxygenase derivatives appear to modulate coronary and cardiac adaptation in the failing heart, we hypothesized that cyclooxygenase derivatives may participate in the altered adrenergic responses in this situation. Isolated hearts from cardiomyopathic (UM-X7.1 subline) and normal hamsters, aged >240 days, were utilized. Coronary and cardiac response to α[sub1]-, β[sub1]-, and β[sub2]-adrenergic stimulations was observed before and after pretreatment with indomethacin, a cyclooxygenase inhibitor. Reduction of coronary flow elicited by α[sub1]-adrenergic stimulation was unchanged in the presence of heart failure, while β[sub1]- and β[sub2]-induced vasodilatations were reduced. Inotropic response to α[sub1] and β[sub1] stimulations were also reduced in failing hearts, while β[sub2]-adrenergic action was unchanged. Pretreatment with indomethacin exacerbated coronary flow reduction observed with α[sub1] stimulation in failing hearts only. Β[sub2]-induced coronary vasodilatation and inotropic response to α[sub1]and &beta[sub2] stimulations were impaired similarly in the presence of indomethacin in normal and failing hearts. The results suggest a complex interaction between adrenergic and cyclooxygenase activation. [ABSTRACT FROM AUTHOR] |
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