Functional organization of brain pathways subserving the baroreceptor reflex: Studies in conscious animals using immediate early gene expression

Roger A.L. Dampney, Jaimie W. Polson, Patrick D. Potts, Yoshitaka Hirooka, Jouji Horiuchi

Research output: Contribution to journalReview article

128 Citations (Scopus)

Abstract

1. This paper reviews studies carried out in our laboratory in which we have used the c-fos functional mapping method, in combination with other methods, to determine the functional organization of central baroreceptor pathways as they operate in the conscious rabbit. 2. First, we showed that periods of induced hypertension or hypotension each result in a specific and reproducible pattern of activation of neurons in the brainstem and forebrain. In particular, hypotension (but not hypertension) results in the activation of catecholamine neurons in the medulla and pons and vasopressin-synthesizing neurons in the hypothalamus. 3. The activation of medullary cell groups in response to induced hypertension or hypotension in the conscious rabbit is almost entirely dependent on inputs from arterial baroreceptors, while the activation of hypothalamic vasopressin-synthesising neurons in response to hypotension is largely dependent on baroreceptors, although an increase in circulating angiotensin also appears to contribute. 4. Discrete groups of neurons in the rostral ventrolateral medulla (RVLM) and A5 area in the pons are the major groups of spinally projecting neurons activated by baroreceptor unloading. In contrast, spinally projecting neurons in the paraventricular nucleus in the hypothalamus appear to be largely unaffected by baroreceptor signals. 5. Direct afferent inputs to RVLM neurons in response to increases or decreases in arterial pressure originate primarily from other medullary nuclei, particularly neurons located in the caudal and intermediate levels of the ventrolateral medulla (CVLM and IVLM), as well as in the nucleus tractus solitarius (NTS). 6. There is also a direct projection from barosensory neurons in the NTS to the CVLM/IVLM region, which is activated by baroreceptor inputs. 7. Collectively, the results of our studies in conscious animals indicate that baroreceptor signals reach all levels of the brain. With regard to the baroreceptor reflex control of sympathetic activity, our studies are consistent with previous studies in anesthetized animals, but in addition reveal other previously unrecognized pathways that also contribute to this reflex regulation.

Original languageEnglish
Pages (from-to)597-616
Number of pages20
JournalCellular and molecular neurobiology
Volume23
Issue number4-5
DOIs
Publication statusPublished - Oct 1 2003

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Immediate-Early Genes
Baroreflex
Pressoreceptors
Gene Expression
Neurons
Brain
Hypotension
Solitary Nucleus
Pons
Hypertension
Vasopressins
Hypothalamus
Rabbits
Paraventricular Hypothalamic Nucleus
Angiotensins
Prosencephalon
Brain Stem
Catecholamines
Reflex
Arterial Pressure

All Science Journal Classification (ASJC) codes

  • Cellular and Molecular Neuroscience
  • Cell Biology

Cite this

Functional organization of brain pathways subserving the baroreceptor reflex : Studies in conscious animals using immediate early gene expression. / Dampney, Roger A.L.; Polson, Jaimie W.; Potts, Patrick D.; Hirooka, Yoshitaka; Horiuchi, Jouji.

In: Cellular and molecular neurobiology, Vol. 23, No. 4-5, 01.10.2003, p. 597-616.

Research output: Contribution to journalReview article

Dampney, Roger A.L. ; Polson, Jaimie W. ; Potts, Patrick D. ; Hirooka, Yoshitaka ; Horiuchi, Jouji. / Functional organization of brain pathways subserving the baroreceptor reflex : Studies in conscious animals using immediate early gene expression. In: Cellular and molecular neurobiology. 2003 ; Vol. 23, No. 4-5. pp. 597-616.
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