Calcitonin gene-related peptide protects against whole body ischemia in a porcine model of cardiopulmonary resuscitation

The Cardiopulmonary Effects of the Calcitonin Gene-related Peptide Family

Cardiopulmonary diseases are very common among the population. They are high-cost diseases and there are still no definitive treatments. The roles of members of the calcitonin-gene related-peptide (CGRP) family in treating cardiopulmonary diseases have been studied for many years and promising results obtained. Especially in recent years, two important members of the family, adrenomedullin and adrenomedullin2/intermedin, have been considered new treatment targets in cardiopulmonary diseases. In this review, the roles of CGRP family members in cardiopulmonary diseases are investigated based on the studies performed to date.

Determination of the site of action of calcitonin gene-related peptide in the alteration of intracellular calcium levels in adult and neonatal rodent myocytes

The purpose of this study is to elucidate the mechanism of action and site of action of calcitonin gene-related peptide (CGRP) and its effects on calcium concentrations in two types of cardiomyocytes, neonatal and adult, by employing real-time fluorescence imaging. CGRP caused an increase in intramyocytic calcium with adult cells, but a decrease with neonates. Treatment of adult myocytes with ouabain and ryanodine yielded results suggesting that CGRP action is not at the ryanodine receptor (RyR) and does not involve Na+ +K+ ATPase. Furthermore, in neonatal cardiomyocytes CGRP caused a reduction in intramyocytic calcium levels, and challenges with ryanodine and ouabain gave results supporting the hypothesis that CGRP acts at the sarcolemmal L-type calcium channel. Employing real-time fluorescence measurements in cultured, dedifferentiated adult cardiomyocytes, which are known to express a fetal phenotype and exhibit neonatal-like calcium transients, our acquisitions demonstrated a major reduction in intracellular calcium levels. Finally, our collaborative studies in human myocardium using fluorescence deconvolution microscopy revealed that CGRP localization was found in a pattern similar to that of the sarcolemmal L-type calcium channel.

The effects of CGRP on calcium transients of dedifferentiating cultured adult rat cardiomyocytes compared to non-cultured adult cardiomyocytes: possible protective and deleterious results in cardiac function

CGRP has potent cardiovascular effects but its role in heart failure is unclear. Effects of CGRP on calcium concentrations in fresh adult rat cardiomyocytes, cultured adult cardiomyocytes and neonatal cardiomyocytes were determined by real time fluorescence spectrophotometry. Treatment of cultured adult cardiomyocytes with CGRP resulted in a rapid cessation of beating and a reduction in intracellular calcium. Similar results were obtained in cultured neonatal myocytes. However, rod-shaped adult cardiomyocytes revealed a number of responses; (a) non-beating cells began to beat with increased intracellular calcium; (b) spontaneously beating cells exhibited increased intracellular calcium content and a faster beating rate or (c), myocytes increased their beating rate and became arrhythmic, suggesting that CGRP action on cultured dedifferentiated adult and neonatal myocytes depletes intracellular calcium, whereas in the rod-shaped mature myocytes calcium is retained, pointing to a different mode of action for CGRP on developing and dedifferentiating cardiomyocytes, compared to fully developed cardiomyocytes.