No effect of endoperoxide 4 or thromboxane A

We investigated the role of cyclooxygenase metabolite-associated endoperoxide 4 receptors (EP4-R) and thromboxane A(2) receptors (TxA(2)-R) on thin fiber muscle afferents in the chronic mechanoreflex sensitization in rats with myocardial infarction-induced heart failure with reduced ejection fraction (HF-rEF). We hypothesized that injection of either the EP4-R antagonist L-161,982 (1 μg) or the TxA(2)-R antagonist daltroban (80 μg) into the arterial supply of the hindlimb would reduce the increase in blood pressure and renal sympathetic nerve activity (RSNA) evoked in response to 30 s of static hindlimb skeletal muscle stretch (a model of isolated mechanoreflex activation) in decerebrate, unanesthetized HF-rEF rats but not sham operated control rats (SHAM). Ejection fraction was significantly reduced in HF-rEF (45±11%) compared to SHAM (83±6%; P