PTGER3 and myocardial infarction: However, beyond the pharmacological modulation and blockage/activation of the EP3 or EP4 receptors, the balance of the natural expression between EP3 and EP4 receptors may play a pivotal role in the cardiovascular system, since it has been reported that the overexpression of EP3 receptor reduces cardiac function under basal conditions and that this is exacerbated after myocardial infarction [27].