Acute exercise and gender alter cardiac autonomic tonus differently in hypertensive and normotensive rats.
*Sex Characteristics; Adrenergic alpha-Antagonists/pharmacology; Animals; Autonomic Nervous System/drug effects/*physiopathology; Blood Pressure; Female; Heart Rate/physiology; Heart/*innervation; Hypertension/*physiopathology; Inbred SHR; Inbred WKY; Male; Metoprolol/pharmacology; N-Methylscopolamine/pharmacology; Parasympathetic Nervous System/drug effects/physiopathology; Parasympatholytics/pharmacology; Physical Exertion/*physiology; Rats; Sympathetic Nervous System/drug effects/physiopathology
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.
Chandler M P; DiCarlo S E
The American journal of physiology
1998
1998-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpregu.1998.274.2.r510" target="_blank" rel="noreferrer noopener">10.1152/ajpregu.1998.274.2.r510</a>
Daily exercise and gender influence postexercise cardiac autonomic responses in hypertensive rats.
*Physical Conditioning; Animal; Animals; Atropine Derivatives/pharmacology; Autonomic Nervous System/drug effects/*physiopathology; Exercise Test; Female; Heart Rate/*drug effects; Heart/*innervation; Hypertension/genetics/*physiopathology; Inbred SHR; Male; Metoprolol/pharmacology; Nitroglycerin/pharmacology; Phenylephrine/pharmacology; Rats; Running; Sex Characteristics; Sympathetic Nervous System/drug effects/*physiopathology; Weight Loss
The influence of daily spontaneous running (DSR) and gender on postexercise cardiac autonomic responses was examined in spontaneously hypertensive rats. Rats were weaned at 4-5 wk of age and were randomly assigned to a sedentary (7 males and 6 females) or DSR (7 males and 8 females) group. After 8 weeks of DSR or sedentary control, rats were chronically instrumented with arterial and venous catheters. After 5 days of recovery, cardiac sympathetic (ST) and parasympathetic tonus (PT) were determined (by the response of heart rate to receptor antagonists) on alternate days under two experimental conditions: no exercise and postexercise. After a single bout of dynamic treadmill exercise (12 m/min, 10% grade for 40 min) ST was reduced (P \textless 0.05) (male sedentary: no exercise 45 +/- 4 vs. postexercise 28 +/- 3 beats/min; female sedentary: no exercise 69 +/- 10 vs. postexercise 37 +/- 7 beats/ min). PT was also altered after exercise (male sedentary: no exercise -31 +/- 4 vs. postexercise -11 +/- 2 beats/min; female sedentary: no exercise -5 +/- 4 vs. postexercise 7 +/- 4 beats/min). After DSR, ST was reduced (male sedentary 45 +/- 4 vs. DSR 22 +/- 3 beats/min; female sedentary 69 +/- 10 vs. DSR 36 +/- 4 beats/min) (P \textless 0.05). Finally, male rats had a lower ST and higher PT than female rats. These results demonstrate that 1) ST was reduced after a single bout of dynamic exercise; 2) ST was reduced after DSR; 3) the autonomic response to acute exercise was attenuated after DSR; and 4) there was a gender influence on the cardiac autonomic function.
Chen Y; Chandler M P; DiCarlo S E
The American journal of physiology
1997
1997-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.1997.272.3.H1412" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.1997.272.3.H1412</a>
Inactivation of one copy of the mouse neurotrophin-3 gene induces cardiac sympathetic deficits.
*Gene Dosage; Aging/metabolism; Animals; Axons/metabolism; Body Weight/genetics; Cell Count; Coronary Vessels/innervation; Heart Rate/genetics; Heart/*innervation; Heterozygote; Homozygote; In Situ Nick-End Labeling; Knockout; Mice; Muscle Tonus/genetics; Mutant Strains; Myocardium/cytology/*metabolism; Neurotrophin 3/deficiency/*genetics; Norepinephrine/metabolism; Organ Size/genetics; Stellate Ganglion/cytology; Sympathetic Nervous System/cytology/*growth & development/metabolism; Tyrosine 3-Monooxygenase/metabolism
Whether two copies of the neurotrophin-3 (NT3) gene are necessary for proper development of cardiac sympathetic innervation was investigated in mice carrying a targeted inactivation of the NT3 gene. Heterozygous (+/-) and null (-/-) mutant mice had fewer stellate ganglion neurons than did wild-type (+/+) mice at postnatal day 0 (P0 or birth), and this deficit was maintained between adult (P60) +/- and +/+ mice. The sympathetic innervation of the heart matured postnatally in +/+ and +/- mice. Tyrosine hydroxylase (TH)-positive axons were restricted largely to the epicardium at P0, were concentrated around large blood vessels in the myocardium at P21, and were present among cardiac myocytes at P60. Cardiac norepinephrine (NE) concentrations paralleled the growth of the sympathetic axons into the heart. NE concentrations were equivalent among +/+, +/-, and -/- mice at birth, but differences between +/- and +/+ mice increased with age. Adult +/- mice also exhibited lower resting heart rates and sympathetic tonus than +/+ mice. Thus deletion of one copy of the NT3 gene translates into anatomical, biochemical, and functional deficits in cardiac sympathetic innervation of postnatal mice, thereby indicating a gene-dosage effect for the NT3 gene.
Story G M; DiCarlo S E; Rodenbaugh D W; Dluzen D E; Kucera J; Maron M B; Walro J M
Physiological genomics
2000
2000-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/physiolgenomics.2000.2.3.129" target="_blank" rel="noreferrer noopener">10.1152/physiolgenomics.2000.2.3.129</a>