Given that P2X is increased and TRPV1 is decreased after induction of myocardial infraction (MI; Smith et al., 2005; Gao et al., 2007), we hypothesized that contraction-induced increase in Tm is attenuated in HF rats and then abnormal Tm response in HF may affect the muscle pressor reflex via temperature-sensitive P2X and TRPV1 (Garcia-Villalon et al., 1997; Wang et al., 2003; Kluess et al., 2005). This evidence concerns the gene TRPV1 and hydrops fetalis.