Abstract | OBJECTIVE: METHODS: The rats were randomly divided into six groups, control group (group I), Iso ( isoproterenol) group (group II), Iso + BRL group (group III), Iso + BRL + low dose of L-NAME group (5 mg/kg, group IV), Iso + BRL + moderate dose of L-NAME group (50 mg/kg, group V), Iso + BRL + high dose of L-NAME group (100 mg/kg, group VI). The hemodynamics [left ventricular end systolic pressure (LVESP), +/- dp/dt, left ventricular end diastolic pressure (LVEDP)], cardiac cGMP and the levels of beta(1)-, beta(2)-, and beta(3)-ARs mRNA were measured. RESULTS: (1) LVESP, +/- dp/dt values in group II were significantly lower, and LVEDP was significantly higher than that in group I (except -dp/dt P < 0.05, the rest were P < 0.01). Comparing with group II, group III had lower -dp/dt value and LVESP, higher LVEDP (P < 0.05). The level of +dp/dt had a trend to be lower but lacked statistical significance between two groups. The value of +/- dp/dt got higher and LVEDP got lower along with higher dose of L-NAME, but a large dose of L-NAME had more deteriorated cardiac functions. (2) The cardiac cGMP in group I, II and III had a higher tendency (P < 0.01). The tendency of cardiac cGMP in group IV, V and VI was inversed with the dose of L-NAME. After a large dose of L-NAME was applied, cGMP returned to the same level as Group I. (3) Among groups I, II and III, the level of beta(1)-AR mRNA was the highest in group I and the lowest in group III (P < 0.01). The levels of beta(2)-AR mRNA were also tended to be lower among three groups but with no significance. While the level of beta(3)-AR mRNA was the highest in group III. The levels of beta-AR mRNA were all the same in group VI, V and VI. CONCLUSIONS: The negative inotropic effect of beta(3)-ARs stimulation was mediated by activation of the NOS pathway. L-NAME blocked beta(3)-ARs agonist negative chronotropic effect on failing heart partly and improved hemodynamics, but a large dose of L-NAME had more deteriorated cardiac functions.
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Authors | Wei-min Li, Yi-hui Kong, Jing-yi Xue, Ying Tian |
Journal | Zhonghua xin xue guan bing za zhi
(Zhonghua Xin Xue Guan Bing Za Zhi)
Vol. 33
Issue 6
Pg. 509-12
(Jun 2005)
ISSN: 0253-3758 [Print] China |
PMID | 16053782
(Publication Type: English Abstract, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Adrenergic Agonists
- RNA, Messenger
- Receptors, Adrenergic, beta-3
- Cyclic GMP
- NG-Nitroarginine Methyl Ester
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Topics |
- Adrenergic Agonists
(therapeutic use)
- Animals
- Cyclic GMP
(metabolism)
- Heart Failure
(drug therapy, metabolism, physiopathology)
- Male
- NG-Nitroarginine Methyl Ester
(administration & dosage, pharmacology)
- RNA, Messenger
(metabolism)
- Rats
- Rats, Wistar
- Receptors, Adrenergic, beta-3
(metabolism)
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