Effects of combined histamine [H.sub.1] and [H.sub.2] receptor blockade on hemodynamic responses to dynamic exercise in males with high-normal blood pressure

• Published in: Applied physiology, nutrition, and metabolism nutrition, and metabolism, 2020-07, Vol.45 (7), p.769
• Main Authors: Naylor, Ashley, Shariffi, Brian, Gillum, Trevor L, William, Boyer, Sullivan, Sean, Kim, Jong-Kyung
• Format: Article
• Language: English
• Subjects: Blood pressure; Comparative analysis; Histamine; Histamine receptors
• ISSN: 1715-5312
• DOI: 10.1139/apnm-2019-0645

While postexercise hypotension is associated with histamine [H.sub.1] and [H.sub.2] receptor-mediated postexercise vasodilation, effects of histaminergic vasodilation on blood pressure (BP) in response to dynamic exercise are not known. Thus, in 20 recreationally active male participants (10 normotensive and 10 with high-normal BP) we examined the effects of histamine Hl and [H.sub.2] receptor blockade on cardiac output (CO), mean atrial pressure (MAP), aortic stiffness (AoStiff), and total vascular conductance (TVC) at rest and during progressive cycling exercise. Compared with the normotensive group, MAP, CO, and AoStiff were higher in the high-normal group before and after the blockade at rest, while TVC was similar. At the 40% workload, the blockade significantly increased MAP in both groups, while no difference was found in the TVC. CO was higher in the high-normal group than the normotensive group in both conditions. At the 60% workload, the blockade substantially increased MAP and decreased TVC in the normotensive group, while there were no changes in the high-normal group. A similar CO response pattern was observed at the 60% workload. These findings suggest that the mechanism eliciting an exaggerated BP response to exercise in the high-normal group may be partially due to the inability of histamine receptors. Novelty * Males with high-normal BP had an exaggerated BP response to exercise. * The overactive BP response is known due to an increase in peripheral vasoconstriction. * Increase in peripheral vasoconstriction is partially due to inability of histamine receptors. Key words: histamine receptors, dynamic exercise, peripheral vasoconstriction, mean arterial pressure, cardiac output, total vascular conductance. Bien que l'hypotension postexercice soit associee a une vasodilatation postexercice mediee par les recepteurs [H.sub.1] et [H.sub.2] de l'histamine, les effets de la vasodilatation histaminergique sur la pression arterielle () en reponse a un exercice dynamique ne sont pas connus. Ainsi, chez 20 hommes actifs par loisir (10 normotendus et 10 avec une BP elevee mais normale), nous examinons les effets du blocage des recepteurs histaminiques [H.sub.1] et [H.sub.2] sur le debit cardiaque (), la pression auriculaire moyenne (), la rigidite aortique () et la conductance vasculaire totale () au repos et pendant un exercice de pedalage par increment. Comparativement au groupe normotendu, la MAP, le CO et l'AoStiff sont plus eleves dans