title: Effects of clonidine on blood pressure and heart rate responses to an emotional stress in the rat: a spectral study.
abstract: 1. The fluctuations that underlie the spontaneous variability of blood pressure (BP) and heart rate (HR) were investigated in conscious normotensive rats using power spectral analysis. 2. Air jet stimulation determined a significant BP rise associated with a tachycardia. This environmental mild stressor amplified the 195-605 mHz oscillations of HR which are under autonomic control. No habituation to this stressor was observed since a second stimulation determined similar responses. 3. Clonidine (10 micrograms/kg, i.v.) prevented the BP rise normally associated with air jet stimulation. In addition, clonidine dramatically reduced the amplitude of BP and HR oscillations in the frequency region of 195-605 mHz. 4. It is concluded that a mild emotional stressor elicits in normotensive rats a rise in BP and HR associated with modified spectral profiles reflecting sympathetic hyperactivity. Clonidine minored the effects of stress on BP and HR variability and also prevented BP elevation.
authors.affiliation: Laboratoire de Pharmacologie, Faculté de Médecine Necker, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Blanc
authors.forename: M L
authors.initials: ML
authors.lastname: Grichois
authors.forename: J L
authors.initials: JL
authors.lastname: Elghozi
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013057:Spectrum Analysis / Q000379:methods; D013315:Stress, Psychological / Q000188:drug therapy / Q000503:physiopathology*
chemical_list: D003000:Clonidine