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Rhythmic Aortic Contractions Induced by Electrical Stimulation In Vivo in the Rat.

Sahibzada N, Mangel AW, Tatge JE, Dretchen KL, Franz MR, Virmani R, Gillis RA - PLoS ONE (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, 3900 Reservoir Road, NW, Washington, DC, 20007, United States of America.

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.

No MeSH data available.


Related in: MedlinePlus

Spontaneous rhythmic contractions (pulse pressure) of the aorta correlated to ECG.(A, B) Representative tracings of aortic contractions (upper panel) and ECG recording (lower panel) before (A) and after (B) bleeding the rat.
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pone.0130255.g003: Spontaneous rhythmic contractions (pulse pressure) of the aorta correlated to ECG.(A, B) Representative tracings of aortic contractions (upper panel) and ECG recording (lower panel) before (A) and after (B) bleeding the rat.

Mentions: Our goal in the first series of experiments was to confirm the earlier findings of Mangel and colleagues [10] obtained in the rabbit, namely, that the rat aorta undergoes spontaneous rhythmic contractions in synchrony with the heartbeat. That this was the case is shown in Fig 3. The traces displayed in part A of the figure are aortic contractions (upper) and the ECG signal (lower). These recordings were made with a Millar catheter placed in the aorta and obtained prior to bleeding the animal. Note the correlation of aortic contraction with the ECG (i.e., the heartbeat). Part B of the figure shows these traces after bleeding the animal. In this condition, rhythmic contraction of the aorta would not be due to transference of contractile activity from other parts of the vascular system. Yet, rhythmic contractions do occur and are correlated with the heartbeat. While these are data from a single rat, the same result was obtained in 3 of 4 rats where PSCs persisted when the rats were bled, and pulsatile pressure changes in the vascular system were eliminated. Removal of the right atrial appendage eliminated PSCs in 2 of 3 rats studied while cardiac contractions persisted.


Rhythmic Aortic Contractions Induced by Electrical Stimulation In Vivo in the Rat.

Sahibzada N, Mangel AW, Tatge JE, Dretchen KL, Franz MR, Virmani R, Gillis RA - PLoS ONE (2015)

Spontaneous rhythmic contractions (pulse pressure) of the aorta correlated to ECG.(A, B) Representative tracings of aortic contractions (upper panel) and ECG recording (lower panel) before (A) and after (B) bleeding the rat.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4489007&req=5

pone.0130255.g003: Spontaneous rhythmic contractions (pulse pressure) of the aorta correlated to ECG.(A, B) Representative tracings of aortic contractions (upper panel) and ECG recording (lower panel) before (A) and after (B) bleeding the rat.
Mentions: Our goal in the first series of experiments was to confirm the earlier findings of Mangel and colleagues [10] obtained in the rabbit, namely, that the rat aorta undergoes spontaneous rhythmic contractions in synchrony with the heartbeat. That this was the case is shown in Fig 3. The traces displayed in part A of the figure are aortic contractions (upper) and the ECG signal (lower). These recordings were made with a Millar catheter placed in the aorta and obtained prior to bleeding the animal. Note the correlation of aortic contraction with the ECG (i.e., the heartbeat). Part B of the figure shows these traces after bleeding the animal. In this condition, rhythmic contraction of the aorta would not be due to transference of contractile activity from other parts of the vascular system. Yet, rhythmic contractions do occur and are correlated with the heartbeat. While these are data from a single rat, the same result was obtained in 3 of 4 rats where PSCs persisted when the rats were bled, and pulsatile pressure changes in the vascular system were eliminated. Removal of the right atrial appendage eliminated PSCs in 2 of 3 rats studied while cardiac contractions persisted.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, 3900 Reservoir Road, NW, Washington, DC, 20007, United States of America.

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.

No MeSH data available.


Related in: MedlinePlus