Document Detail

Transient beta adrenergic stimulation can precondition the rat heart against postischaemic contractile dysfunction.
MedLine Citation:
PMID:  7842468     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: The aim was to assess the abilities of exogenous noradrenaline, isoprenaline, and phenylephrine to precondition the isolated rat heart against ischaemic and reperfusion injury. METHODS: The isovolumetric Langendorff rat heart model was used to determine postischaemic recovery of left ventricular function. The hearts were subjected to 30 min of normothermic global ischaemia followed by 30 min reperfusion. Treated hearts were perfused with noradrenaline (10(-7) M), isoprenaline (10(-8) M), or phenylephrine (10(-6) M, 10(-5) M, and 10(-4) M) for 5 min followed by 5 min washout before the 30 min ischaemic period. RESULTS: Control hearts recovered 47.6(SEM 4.3)% of baseline heart rate x developed pressure after 30 min reperfusion, whereas noradrenaline and isoprenaline treated hearts recovered 75.1(4.6) and 76.4(4.6)%, respectively (p < 0.001 v control). Left ventricular end diastolic pressures at the end of reperfusion were 48.8(4.0), 20.0(2.4), and 21.6(2.7)mm Hg for control, noradrenaline treated (p < 0.001 v control), and isoprenaline treated (p < 0.001 v control) hearts respectively. beta Blockade with propranolol during noradrenaline treatment blocked the protective effects. No concentration of phenylephrine used was able to enhance postischaemic heart rate x developed pressure significantly, or result in improved (lower) postischaemic left ventricular end diastolic pressure. During treatment with noradrenaline and phenylephrine (10(-5) M), lactate release was 13.0(1.0) and 11.0(0.9) mumol.5 min-1, respectively (p = NS); these values were significantly (p < 0.001) greater than baseline value of 3.7(0.5) mumol.5 min-1. Immediately before the 30 min ischaemic period, control and phenylephrine treated groups had glycogen levels of 132(14) and 128(5) protein, respectively (p = NS), whereas the glycogen content of the noradrenaline treated group was only 96(5) protein (p < 0.05 v control and phenylephrine treated). CONCLUSIONS: Transient beta adrenergic but not alpha 1 adrenergic stimulation can precondition the isolated perfused rat heart. The mechanism of protection may, at least in part, be due to transient demand ischaemia. Partial depletion of glycogen following treatment may play a role in the observed protective effects.
G K Asimakis; K Inners-McBride; V R Conti; C J Yang
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cardiovascular research     Volume:  28     ISSN:  0008-6363     ISO Abbreviation:  Cardiovasc. Res.     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1995-03-06     Completed Date:  1995-03-06     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0077427     Medline TA:  Cardiovasc Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1726-34     Citation Subset:  IM    
University of Texas Medical Branch, Galveston 77555-0528.
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MeSH Terms
Adrenergic beta-Agonists / pharmacology*
Arrhythmias, Cardiac / prevention & control*
Glycogen / metabolism
Heart / drug effects
Isoproterenol / pharmacology
Myocardial Contraction / drug effects
Myocardial Ischemia / metabolism*
Myocardial Reperfusion Injury / prevention & control
Myocardium / metabolism*
Norepinephrine / pharmacology
Phenylephrine / pharmacology
Rats, Sprague-Dawley
Stimulation, Chemical
Reg. No./Substance:
0/Adrenergic beta-Agonists; 51-41-2/Norepinephrine; 59-42-7/Phenylephrine; 7683-59-2/Isoproterenol; 9005-79-2/Glycogen
Comment In:
Cardiovasc Res. 1994 Dec;28(12):1872-3   [PMID:  7867042 ]

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