Effect of chronic IL-6 infusion on acute pressor responses to vasoconstrictors in mice.

Abstract

Interleukin (IL)-6 has been implicated as a contributing factor in the pathogenesis of hypertension, although the mechanisms involved are unclear. Studies conducted in vitro suggest that IL-6 may have a direct effect on vascular tone and may modulate constrictor responses to agonists. Whether this effect can be observed in vivo is unknown. Therefore, mice were treated with either IL-6 (16 ng/h sc) or vehicle for 14 days, and the acute blood pressure and heart rate responses to endothelin (ET)-1, angiotensin II (ANG II), and phenylephrine (PE) were assessed under isoflurane anesthesia. Blood pressure responses to ET-1 were identical in vehicle- and IL-6-infused mice, both in the presence and the absence of ganglion blockade with chlorisondamine. The fall in heart rate during ET-1 responses was significantly attenuated in IL-6-infused mice with autonomic reflexes intact (vehicle vs. IL-6, P < 0.05 at 1 and 3 nmol/kg of ET-1), but this difference was not observed after ganglionic blockade. Both blood pressure and heart rate responses to ANG II were indistinguishable between IL-6- and vehicle-infused mice, as were responses to PE except for a significant increase in the blood pressure response and decrease in the heart rate response in IL-6-infused mice observed only at the highest dose of PE (300 microg/kg; P < 0.05). These findings show that, despite what might be predicted from studies conducted in vitro, chronic exposure to elevated plasma IL-6 concentrations in itself does not predispose the mouse to enhanced responsiveness to vasoconstrictors in vivo.

• Authors: Erika I Boesen, David M Pollock
• Journal: American journal of physiology. Heart and circulatory physiology (Am J Physiol Heart Circ Physiol) Vol. 293 Issue 3 Pg. H1745-9 (Sep 2007) ISSN: 0363-6135 [Print] United States
• PMID: 17557918 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Endothelin-1
• Interleukin-6
• Vasoconstrictor Agents
• Angiotensin II
• Phenylephrine

Topics

• Angiotensin II (pharmacology)
• Animals
• Blood Pressure (drug effects, physiology)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Endothelin-1 (pharmacology)
• Heart Rate (drug effects, physiology)
• Hypertension (etiology, physiopathology)
• Interleukin-6 (blood, physiology)
• Male
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Phenylephrine (pharmacology)
• Pressoreceptors (drug effects, physiology)
• Vasoconstrictor Agents (pharmacology)