Effects of in-vivo 3-iodothyronamine administration on gene expression in cardiac tissue

3-iodothyronamine (T1AM) is an endogenous compound, which shares structural and functional features with biogenic amines and is able to interact with a specific class of receptors, named trace amine associated receptors (TAARs). T1AM exerts in mammals significant physiological effects, which are often opposite to those produced by the thyroid hormone (TH). In particular, in the heart, T1AM produces reversible, dose-dependent negative inotropic and chronotropic effects. In addiction, a T1AM induced cardio-protective effect in isolated rat hearts subjected to ischemia and reperfusion has been recently observed. Aim of this work was to study the effects of in vivo T1AM administration on gene expression in rat cardiac tissue. Eight Wistar rats were treated with T1AM for five days (10 mg/kg per day by i.p. injection). The rats were then sacrificed by guillotine and heart tissue samples were immediately removed and frozen in liquid nitrogen. Gene expression was evaluated by two-colour microarray analysis, using the whole rat genome G4131F microarrays (Agilent Technologies, Palo Alto, CA, USA). Significant differences in gene expression were validated by quantitative RT-PCR. We observed the differential expression of 129 genes, 80 up-regulated and 49 down-regulated, many of them involved in cardiac function, cardioprotection and circadian rhythm. In vivo T1AM administration, therefore, produced significant transcriptional effects in cardiac tissue, which are consistent with the observed phenotype.