title: Reduced hemodynamic responses to physical and mental stress under low-dose rilmenidine in healthy subjects.
abstract: Activation of the sympathetic nervous system plays a major role in the pathogenesis and prognosis of cardiovascular diseases. Rilmenidine is an I(1)-imidazoline receptor agonist that reduces blood pressure by modulation of central sympathetic activity, but the effects of low-dose rilmenidine on the hemodynamic responses to physiological maneuvers that increase adrenergic drive is not known. To assess the effects of low-dose rilmenidine on the hemodynamic responses to stress, 32 healthy subjects (20-56 years old) underwent acute physical exercise (n = 15, individualized ramp protocol on treadmill) and mental stress (n = 17, word color Stroop and mental arithmetics tests) two hours after the oral administration of 0.5 mg of rilmenidine (RIL) or placebo (PLA) following a randomized, double-blind, placebo controlled crossover study. No subject complained of any side effect. Rilmenidine reduced peak exercise heart rate (PLA: 187 +/- 7; RIL: 181 +/- 9 bpm; P = 0.003), but did not modify peak aerobic power (VO(2max) - PLA: 41.7 +/- 6.2; RIL: 42.3 +/- 6.7 ml/kg/min; P = 0.26). During mental stress, rilmenidine inhibited the peak systolic (PLA: 123 +/- 10; RIL: 114 +/- 8 mmHg; P = 0.02) and diastolic (PLA: 86 +/- 7; RIL: 81 +/- 7 mmHg; P <0.05) blood pressure responses. In conclusion, rilmenidine reduced the hemodynamic response to physical and mental stress stimuli without limiting exercise capacity. These results support the concept that rilmenidine, at a dose lower than the ones recommended to treat hypertension, reduced the myocardial oxygen demand to stress and may carry potential clinical impact.
authors.affiliation: Departament of Physiology and Pharmacology, Instituto Biomédico, Universidade Federal Fluminense, Rua Prof. Hernani Melo, 101 Niterói, RJ, Brazil CEP 24210-131.
authors.forename: Renata Rodrigues
authors.initials: RR
authors.lastname: Teixeira de Castro
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tibiriçá
authors.forename: Marcos Aurélio Brazão
authors.initials: MA
authors.lastname: de Oliveira
authors.forename: Paula Barbosa Baptista
authors.initials: PB
authors.lastname: Moreira
authors.forename: Marcelo Flores
authors.initials: MF
authors.lastname: Catelli
authors.forename: Nazareth Novaes
authors.initials: NN
authors.lastname: Rocha
authors.forename: Antonio C L
authors.initials: AC
authors.lastname: Nóbrega
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000187:drug effects / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010080:Oxazoles / Q000008:administration & dosage / Q000494:pharmacology*; D010809:Physical Fitness / Q000502:physiology / Q000523:psychology; D000077769:Rilmenidine; D013315:Stress, Psychological / Q000503:physiopathology*
chemical_list: D000959:Antihypertensive Agents; D010080:Oxazoles; D000077769:Rilmenidine