Introduction:

Cardiomyocytes have a biochemical machinery with the capacity to synthesize, utilize and reuptake serotonin.

Objective:

To determine whether hypertrophic cardiomyopathy (HCM) induces changes in the expression of tryptophan-5-hydroxylase (TPH) 1 and 2, serotonin transporter (SERT) and serotonergic receptors (SR).

Methods:

Cross-sectional study of five tissue blocks from hearts with HCM and five controls. Five sections of the left ventricular free wall (LVFW) and interventricular septum (IVS) were obtained from each block to determine the expression of TPH1 and TPH2, SERT and SRs by immunofluorescence with specific antibodies. Immunofluorescence was evaluated by WELCH t-test, with a level of significance of p < 0.05.

Results:

LVFW and IVS of hearts with HCM showed an increase in the expression of TPH1 and TPH 2 and 5-HT2A and 5-HT2B receptors in comparison with controls (p < 0.01). The 5-HT4 receptor and SERT showed an increase in the IVS of hearts with HCM (p < 0.01).

Conclusions:

This study demonstrated an increased expression of TPH, SERT and SRs in cardiomyocytes from hearts with HCM in comparison with controls, which could be involved in the pathophysiology of HCM in humans.