Functional magnetic resonance signal changes in neural structures to baroreceptor reflex activation

Luke A. Henderson, Chris A. Richard, Paul M. Macey, Matthew L. Runquist, Pearl L. Yu, Jean-Philippe Galons, Ronald M. Harper

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

The sequence of neural responses to exogenous arterial pressure manipulation remains unclear, especially for extramedullary sites. We used functional magnetic resonance imaging procedures to visualize neural responses during pressor (phenylephrine) and depressor (sodium nitroprusside) challenges in seven isoflurane-anesthetized adult cats. Depressor challenges produced signal-intensity declines in multiple cardiovascular-related sites in the medulla, including the nucleus tractus solitarius, and caudal and rostral ventrolateral medulla. Signal decreases also emerged in the cerebellar vermis, inferior olive, dorsolateral pons, and right insula. Rostral sites, such as the amygdala and hypothalamus, increased signal intensity as arterial pressure declined. In contrast, arterial pressure elevation elicited smaller signal increases in medullary regions, the dorsolateral pons, and the right insula and signal declines in regions of the hypothalamus, with no change in deep cerebellar areas. Responses to both pressor and depressor challenges were typically lateralized. In a subset of animals, barodenervation resulted in rises and falls of blood pressure that were comparable to these resulting from the pharmacological challenges but different regional neural responses, indicating that the regional signal intensity responses did not derive from global perfusion effects but from baroreceptor mediation of central mechanisms. The findings demonstrate widespread lateralized distribution of neural sites responsive to blood pressure manipulation. The distribution and time course of neural responses follow patterns associated with early and late compensatory reactions.

Original languageEnglish (US)
Pages (from-to)693-703
Number of pages11
JournalJournal of Applied Physiology
Volume96
Issue number2
DOIs
StatePublished - Feb 2004

Fingerprint

Baroreflex
Arterial Pressure
Magnetic Resonance Spectroscopy
Pons
Hypothalamus
Blood Pressure
Pressoreceptors
Solitary Nucleus
Isoflurane
Nitroprusside
Phenylephrine
Amygdala
Cats
Perfusion
Magnetic Resonance Imaging
Pharmacology

Keywords

  • Barodenervation
  • Baroreflex
  • Blood pressure
  • Heart rate
  • Respiration

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Functional magnetic resonance signal changes in neural structures to baroreceptor reflex activation. / Henderson, Luke A.; Richard, Chris A.; Macey, Paul M.; Runquist, Matthew L.; Yu, Pearl L.; Galons, Jean-Philippe; Harper, Ronald M.

In: Journal of Applied Physiology, Vol. 96, No. 2, 02.2004, p. 693-703.

Research output: Contribution to journalArticle

Henderson, Luke A. ; Richard, Chris A. ; Macey, Paul M. ; Runquist, Matthew L. ; Yu, Pearl L. ; Galons, Jean-Philippe ; Harper, Ronald M. / Functional magnetic resonance signal changes in neural structures to baroreceptor reflex activation. In: Journal of Applied Physiology. 2004 ; Vol. 96, No. 2. pp. 693-703.
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