title: Acute exercise and gender alter cardiac autonomic tonus differently in hypertensive and normotensive rats.
abstract: Arterial pressure (AP), heart rate (HR), cardiac sympathetic tonus (ST), and parasympathetic tonus (PT) were determined in spontaneously hypertensive rats (SHR, 8 male and 8 female) and Wistar-Kyoto normotensive rats (WKY, 8 male and 12 female) before and after acute exercise. Before exercise, hypertensive rats (regardless of gender) had an increased ST (+15 beats/min), increased resting HR (+12 beats/min), and decreased PT (-11 beats/min). Similarly, female rats (regardless of strain) also had an increased ST (+15 beats/min), increased resting HR (+39 beats/min), and decreased PT (-14 beats/min). Hypertensive rats had a significant reduction in AP (-17 +/- 3 mmHg), ST (-26 beats/min), PT (-7 beats/min), and HR (-14 beats/min) after exercise. In contrast, AP was not reduced in normotensive rats and ST (+18 beats/min) and HR (+42 beats/min) were increased in female normotensive rats after exercise. However, male normotensive rats had a postexercise reduction in ST (-14 beats/min) and HR (-19 beats/min). In summary, AP, ST, and resting HR were higher whereas PT was lower in hypertensive vs. normotensive rats. Furthermore, females had a higher resting HR, intrinsic HR, and ST and lower PT than male rats. These data demonstrate that gender and the resting level of AP influence cardiac autonomic regulation.
authors.affiliation: Department of Physiology, College of Medicine, Northeastern Ohio Universities, Rootstown 44272, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Chandler
authors.forename: S E
authors.initials: SE
authors.lastname: DiCarlo
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D001794:Blood Pressure; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000502:physiology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D019832:N-Methylscopolamine / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D010276:Parasympatholytics / Q000494:pharmacology; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012727:Sex Characteristics; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology
chemical_list: D000317:Adrenergic alpha-Antagonists; D010276:Parasympatholytics; D008790:Metoprolol; D019832:N-Methylscopolamine