Exaggerated sympathetic and cardiovascular responses to dynamic mechanoreflex activation in rats with heart failure: Role of endoperoxide 4 and thromboxane A < sub > 2 < /sub > receptors

Auton Neurosci. 2021 Feb 13;232:102784. doi: 10.1016/j.autneu.2021.102784. Online ahead of print.ABSTRACTThe primary purpose of this investigation was to determine the role played by endoperoxide 4 receptors (EP4-R) and thromboxane A2 receptors (TxA2-R) during isolated dynamic muscle mechanoreflex activation in rats with heart failure with reduced ejection fraction (HF-rEF) and sham-operated healthy controls. We found that injection of the EP4-R antagonist L-161,982 (1 μg) into the arterial supply of the hindlimb had no effect on the peak pressor response to dynamic hindlimb muscle stretch in HF-rEF (n = 6, peak ∆MAP pre: 27 ± 7; post: 27 ± 4 mm Hg; P = 0.99) or sham (n = 6, peak ∆MAP pre: 15 ± 3; post: 13 ± 3 mm Hg; P = 0.67) rats. In contrast, injection of the TxA2-R antagonist daltroban (80 μg) into the arterial supply of the hindlimb reduced the pressor response to dynamic hindlimb muscle stretch in HF-rEF (n = 11, peak ∆MAP pre: 28 ± 4; post: 16 ± 2 mm Hg; P = 0.02) but not sham (n = 8, peak ∆MAP pre: 17 ± 3; post: 16 ± 3; P = 0.84) rats. Our data suggest that TxA2-Rs on thin fibre muscle afferents contribute to the exaggerated mechanoreflex in HF-rEF.PMID:33610008 | DOI:10.1016/j.autneu.2021.102784

Source: Autonomic Neuroscience - February 20, 2021 Category: Neuroscience Authors: Alec L E Butenas Korynne S Rollins Auni C Williams Shannon K Parr Stephen T Hammond Carl J Ade K Sue Hageman Timothy I Musch Steven W Copp Source Type: research