title: Chronic cholinergic stimulation promotes changes in cardiovascular autonomic control in spontaneously hypertensive rats.
abstract: Hypertension is often accompanied by autonomic dysfunction, which is detrimental to cardiac regulation. On the other hand, cholinergic stimulation through inhibition of acetylcholinesterase appears to have beneficial effects on cardiac autonomic control. Thus, our objective was to investigate the effects of chronic cholinergic stimulation on hemodynamic and cardiovascular autonomic control parameters in spontaneously hypertensive rats (SHR). For this, 26-week-old SHR (N = 32) and Wistar Kyoto rats (WK; N = 32) were divided into two groups: one treated with vehicle (H2O; N = 16) and the other treated with pyridostigmine bromide (PYR; N = 16) in drinking water (25 mg/kg/day) for 2 weeks. All groups were subjected to recording of arterial pressure (AP) and heart rate (HR), quantification of ejection fraction (EF), evaluation of cardiac tonic autonomic balance by means of double autonomic blockade with methylatropine and propranolol, analysis of systolic AP (SAP) and HR variability (HRV), and evaluation of baroreflex sensitivity (BRS). AP, HR, and EF were reduced in the SHR-PYR group compared with the SHR-H2O group. Evaluation of autonomic parameters revealed an increase in vagal tone participation in cardiac tonic autonomic balance and reduced SAP variability; however, no changes were observed in HRV or BRS. These results suggest that chronic cholinergic stimulation with pyridostigmine bromide promotes reduction in the hemodynamic parameters AP, HR, and EF. Additionally, tonic autonomic balance was improved and a reduction in LF oscillations of SAP variability was observed that could not be attributed to BRS, as the latter did not change. Further studies should be conducted to identify the mechanisms involved in the observed responses.
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: João H D
authors.initials: JH
authors.lastname: Blanco
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Ada C
authors.initials: AC
authors.lastname: Gastaldi
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Camila B
authors.initials: CB
authors.lastname: Gardim
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: João E
authors.initials: JE
authors.lastname: Araujo
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Marcus V
authors.initials: MV
authors.lastname: Simões
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Luciano F L
authors.initials: LF
authors.lastname: Oliveira
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Eduardo E V
authors.initials: EE
authors.lastname: Carvalho
authors.affiliation: Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil. Electronic address: hugocds@fmrp.usp.br.
authors.forename: Hugo C D
authors.initials: HC
authors.lastname: Souza
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D017704:Baroreflex / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004195:Disease Models, Animal; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D011729:Pyridostigmine Bromide / Q000494:pharmacology; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013318:Stroke Volume / Q000187:drug effects / Q000502:physiology*; D014630:Vagus Nerve / Q000187:drug effects / Q000503:physiopathology
chemical_list: D002800:Cholinesterase Inhibitors; D011729:Pyridostigmine Bromide
keywords: Cardiovascular autonomic control; Hypertension;; Pyridostigmine bromide;