Die Regulation der ANP-Freisetzung bei Herzinsuffizienz
BJECTIVE: Plasma levels of atrial natriuretic peptide (ANP) are markedly increased in congestive heart failure. ANP has been shown to be released by cardiomyocytes during atrial (and thereby cardiomyocytical) stretch. Several factors that are activated in heart failure as well enhance ANP release through the interaction with G(alpha-q)-coupled receptors and the consequent activation of proteinkinase C (PKC). The goal of this study was to analyse stretch induced ANP secretion and to investigate the involvement of PKC in the regulation of ANP release in heart failure compared to normal hearts. METHODS: Volume overload induced heart failure was produced by an infrarenal aortocaval shunt (4 weeks) in Wistar rats. ANP release was analysed in an isolated retrogradly perfused heart preparation. Atrial stretch was induced by switching to anterograd perfusion (perfusion pressure: 10mmHg). For PKC activation PMA (phorbol 12 myristate 13 acetate) was added to the perfusate and compar! ed to vehicle treatment. All experiments were performed with shunt and sham operated rats. RESULTS AND CONCLUSIONS: After shunt operation ANP baseline release was considerably augmented and could thus explain elevated ANP plasma levels in heart failure patients. In contrast, atrial stretch as an adequate secretion stimulus in control hearts did not further enhance ANP release in hearts of shunt operated animals. The ANP secretion in heart failure therefore seems to differ from the ANP secretion in the healthy state. Stimulation of PKC markedly decreased ANP release in the shunt group, whereas it did not have any significant effect on ANP release in the control group. In conclusion, the role of the proteinkinase C in ANP release differs between normal and failing hearts and seems to be involved in the deviating regulation of ANP release in states of heart failure.
School:Humboldt-Universität zu Berlin
Source Type:Master's Thesis
Keywords:heart failure Atriales natriuretisches Peptid Phorbolester Shunt atrial natriuretic peptide stretch phorbolester shunt
Date of Publication:09/13/2005