title: Lisinopril indifferently improves heart rate variability during day and night periods in spontaneously hypertensive rats.
abstract: The aim of this work was to investigate the effect of 10 weeks of lisinopril treatment to spontaneously hypertensive rats (SHRs) on day/night variations of blood pressure, heart rate and autonomic cardio-regulation parameters. Male SHR with surgically implanted radio-telemetry implant that provided direct measurements of arterial pressure and electrocardiogram wave were used. Animals were allocated to two groups (n=5 each). The first group was treated with lisinopril (20 mg/kg by gavage) daily for 10 weeks (treated group); whereas the second was gavaged daily with tap water (untreated group). Arterial blood pressure, ECG and other telemetry parameters were recorded at the start and at the end of 10-week treatment. Collected data were analyzed using specialized software and were statistically tested. In addition to the expected lowering of blood pressure, spectral analysis of R-R intervals revealed that lisinopril treatment for 10 weeks significantly caused 2-3 fold increase in heart rate variability (HRV) during both active and inactive periods. However, R-R interval durations demonstrated variable distribution patterns during those periods. The cause of observed distribution pattern of R-R intervals during active and inactive periods may be of significance to better understand HRV changes and warrants further investigations.
authors.affiliation: Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khod, Muscat, Sultanate of Oman. salbarwani@squ.edu.om
authors.forename: S
authors.initials: S
authors.lastname: Albarwani
authors.forename: S
authors.initials: S
authors.lastname: Al-Siyabi
authors.forename: M O
authors.initials: MO
authors.lastname: Tanira
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage; D001341:Autonomic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects*; D002940:Circadian Rhythm / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D017706:Lisinopril; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents; D017706:Lisinopril