title: Rhythmic Aortic Contractions Induced by Electrical Stimulation In Vivo in the Rat.
abstract: For over a century, the behavior of the aorta and other large arteries has been described as passive elastic tubes in which no active contraction occurs in the smooth muscle wall. In response to pulsatile pressure changes, the vessels undergo a 'passive' elastic dilatation-contraction cycle, described as a "Windkessel" effect. However, Mangel and colleagues have presented evidence that is contrary to this view. They reported that in the rabbit, the aorta undergoes rhythmic 'active' (contraction) during the cardiac cycle; but these findings have been largely ignored. In the present study, we observed spontaneous contractions in synchrony with the heartbeat in another species (rat). In addition we demonstrate that aorta contractions are of neurogenic origin. Electrical stimulation of the aorta evoked contractions that occur at a rate that is in the range of the animal's heartbeat and are suppressed by tetrodotoxin and the alpha-adrenergic receptor blocker, phentolamine. Altogether, these findings indicate that aortic contractions are under neural control from the heart.
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, 3900 Reservoir Road, NW, Washington, DC, 20007, United States of America.
authors.forename: Niaz
authors.initials: N
authors.lastname: Sahibzada
authors.affiliation: RTI Health Solutions, 3090 Cornwallis Drive, Research Triangle Park, NC, 27709, United States of America.
authors.forename: Allen W
authors.initials: AW
authors.lastname: Mangel
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, 3900 Reservoir Road, NW, Washington, DC, 20007, United States of America.
authors.forename: Jaclyn E
authors.initials: JE
authors.lastname: Tatge
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, 3900 Reservoir Road, NW, Washington, DC, 20007, United States of America.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Dretchen
authors.affiliation: Cardiology Division, Veterans Affairs Medical Center, 50 Irving St, NW, Washington, DC, 20422, United States of America.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Franz
authors.affiliation: CVPath Institute, Gaithersburg, Maryland, 20878, United States of America.
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, 3900 Reservoir Road, NW, Washington, DC, 20007, United States of America.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Gillis
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology*; D001683:Biological Clocks; D004558:Electric Stimulation; D008297:Male; D009119:Muscle Contraction; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction