Relationship between arterial distensibility and low-frequency power spectrum of blood pressure in spontaneously hypertensive rats.
The aim of this study was to determine in spontaneously hypertensive rats (SHRs) whether a significant association may be observed between the low-frequency component of blood pressure variability (BPV) and arterial distensibility and to evaluate the role of the autonomic nervous system in this relationship. Doxazosin (1 mg/kg/d s.c.), flesinoxan (1 mg/kg/d s.c.), and urapidil (30 mg/kg/d s.c.) were infused over 24 h in SHRs. Blood pressure was recorded in conscious rats and BPV was characterized by spectral analysis. The distensibility-pressure curves for the carotid artery were determined by an ultrasonic echo-tracking device in anesthetized rats. Untreated SHRs had higher mean arterial pressure (MAP) and low-frequency MAP but a lower distensibility than normotensive Wistar-Kyoto rats. In SHRs inhibition of the autonomic nervous system by peripheral blockade of alpha1-adrenoceptors (doxazosin, 1 mg/kg, or urapidil, 30 mg/kg) or centrally mediated reduction of sympathetic tone (flesinoxan, 1 mg/kg) reduced MAP and low-frequency MAP in the conscious state and increased carotid operational distensibility in the anesthetized state. In these SHRs, we observed a negative association between low-frequency MAP and operational distensibility ( r = -0.48, p < 0.01). From multiple regression analysis, MAP and low-frequency MAP, but not drug treatment, influenced arterial distensibility. Our study in SHRs provides evidence for a strong association between increased low-frequency MAP and reduced arterial distensibility, with a common modulation provided by the autonomic nervous system via the alpha 1 -adrenergic receptor component and central nervous system.
Dabiré
Hubert
H
Institut National de la Santé et de la Recherche Médicale, Paris, France.
Lacolley
Patrick
P
Chaouche-Teyara
Kamel
K
Fournier
Berthe
B
Safar
Michel E
ME
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D017536:Carotid Artery, Common / Q000187:drug effects* / Q000502:physiology; D017292:Doxazosin / Q000494:pharmacology; D015150:Echocardiography, Doppler; D008297:Male; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011985:Receptors, Serotonin / Q000187:drug effects; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000502:physiology; D018924:Vascular Capacitance / Q000187:drug effects / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists; C056895:flesinoxan; C015568:urapidil; D017292:Doxazosin