Acute stress increases venomotor tone in conscious rats.
This study tested the hypothesis that acute psychological stress causes venoconstriction. Male Sprague-Dawley rats were instrumented with indwelling catheters in a femoral artery and vein and a balloon-tipped catheter in the right atrium. Mean arterial pressure (MAP), venous pressure, heart rate (HR), and mean circulatory filling pressure (MCFP) were monitored in conscious rats. Air-jet stress was performed before and after treatment with saline, chlorisondamine, phentolamine, or prazosin. Air-jet stress caused MAP, HR, and MCFP to increase by 10 +/- 1 mmHg, 31 +/- 4 beats/min, and 0.95 +/- 0.09 mmHg, respectively. Treatment with either chlorisondamine or phentolamine was equally effective in abolishing the stress-induced increases in MAP, HR, and MCFP. Prazosin treatment abolished the pressor response to air-jet stress but did not significantly affect the HR and MCFP responses. In contrast, pretreatment with the alpha 2-receptor antagonist rauwolscine hydrochloride abolished both the MAP and MCFP responses to air-jet stress but did not affect the HR response. These findings indicate that venoconstriction is an important component of the cardiovascular response to acute psychological stress. Stress-induced venoconstriction appears to be mediated primarily via the alpha 2-receptor subtype.
Department of Physiology and Pharmacology, University of South Dakota, Vermillion 57069, USA.
D S
DS
Martin
C
C
Appelt
M C
MC
Rodrigo
M C
MC
Egland
D000208:Acute Disease; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001341:Autonomic Nervous System / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D012039:Regional Blood Flow; D013312:Stress, Physiological / Q000503:physiopathology*; D014666:Vasomotor System / Q000503:physiopathology*; D014680:Veins / Q000503:physiopathology*
D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha