Contribution of serotonin uptake and degradation to myocardial interstitial serotonin levels during ischaemia-reperfusion in rabbits.
Acta Physiol (Oxf) 2013;
207:260-8. [PMID:
22687057 DOI:
10.1111/j.1748-1716.2012.02461.x]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/19/2012] [Accepted: 06/06/2012] [Indexed: 01/02/2023]
Abstract
AIM
Although deleterious effects of serotonin (5-HT) have been demonstrated during myocardial ischaemia-reperfusion, little information is available on myocardial interstitial 5-HT kinetics. This study evaluated the contribution of 5-HT reuptake and degradation to myocardial interstitial 5-HT levels during ischaemia-reperfusion.
METHODS
Using microdialysis technique in anaesthetized rabbits, we monitored myocardial interstitial 5-HT levels in the ischaemic region during ischaemia (30 min) followed by reperfusion (60 min) and investigated the effects of local infusion of fluoxetine, a 5-HT uptake inhibitor, and/or pargyline, a monoamine oxidase inhibitor.
RESULTS
In vehicle control, dialysate 5-HT concentration increased gradually from 16 ± 3 at baseline to 85 ± 18 nM during 20-30 min of ischaemia. Dialysate 5-HT concentration further increased to 236 ± 47 nM at 0-10 min of reperfusion and then began to decline. Averaged 5-HT concentration was 61 ± 11 during ischaemia and 113 ± 13 nM during reperfusion. Fluoxetine elevated dialysate 5-HT level at baseline and at 10-30 min of reperfusion; it increased averaged dialysate 5-HT concentration by approx. 304% during reperfusion compared to control. Pargyline elevated averaged dialysate 5-HT concentration during ischaemia by approx. 243% and that during reperfusion by approx. 250% compared to control. The changes in dialysate 5-HT concentration by fluoxetine + pargyline were similar to those of fluoxetine alone.
CONCLUSION
The 5-HT reuptake function plays an important role in the clearance of myocardial interstitial 5-HT during reperfusion. When 5-HT reuptake function is intact, degradation of 5-HT by monoamine oxidase contributes to reduce myocardial interstitial 5-HT level throughout ischaemia-reperfusion.
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