What is the clinical evidence from this study?

Intervention: Pressor (phenylephrine) and depressor (sodium nitroprusside) challenges. Primary outcome: Neural responses (signal-intensity changes) visualized by fMRI.

What question did this study set out to answer?

To investigate neural responses to arterial pressure manipulation and the role of baroreceptor reflex in these responses.

January 31, 2004Journal of Applied Physiology

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

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Key result

Pressor and depressor challenges in anesthetized cats elicited widespread, lateralized functional magnetic resonance signal changes in medullary and extramedullary neural structures.

Why the study?

Does arterial pressure manipulation alter functional magnetic resonance signals in neural structures in anesthetized cats?

Population

7 isoflurane-anesthetized adult cats

Comparison

Pressor and depressor challenges vs Barodenervation in a subset of animals

Design

Preclinical

Authors

LHLuke A. HendersonCardiac Surgery CRC RichardUniversity of California, Los Angeles PMPaul M. MaceyAllen Institute for Brain Science

Discussion

Member takes

Implication

Animal findings on pressure-evoked fMRI signals require validation before human use; leaves open extramedullary baroreflex mapping in conscious subjects.

Key Points

To investigate neural responses to arterial pressure manipulation and the role of baroreceptor reflex in these responses.
Used functional magnetic resonance imaging in seven isoflurane-anesthetized adult cats.
Assessed neural responses during depressor (sodium nitroprusside) and pressor (phenylephrine) challenges.
Evaluated signal intensity changes across various brain regions associated with cardiovascular function.
Depressor challenges led to signal intensity declines in cardiovascular-related medullary sites such as the nucleus tractus solitarius (p<0.05).
Rostral sites like the amygdala showed increased signal intensity when arterial pressure declined (p<0.05).
Barodenervation resulted in distinct regional neural responses to blood pressure changes compared to pharmacological challenges.

Structured PICO

Does arterial pressure manipulation alter functional magnetic resonance signals in neural structures in anesthetized cats?

Population

7 isoflurane-anesthetized adult cats subjected to pressor and depressor challenges.

Intervention

Pressor (phenylephrine) and depressor (sodium nitroprusside) challenges

Comparator

Barodenervation in a subset of animals

Outcome

Functional magnetic resonance signal changes in neural structuressurrogate

The study demonstrates widespread lateralized distribution of neural sites responsive to blood pressure manipulation, mediated by central baroreceptor mechanisms.

Cite This Study

Henderson et al. (2004) studied this question. Pressor (phenylephrine) and depressor (sodium nitroprusside) challenges was evaluated on Neural responses (signal-intensity changes) visualized by fMRI. Pressor and depressor challenges in anesthetized cats elicited widespread, lateralized functional magnetic resonance signal changes in medullary and extramedullary neural structures.

synapsesocial.com/papers/6a5d2f13289a75eadbc27158 https://doi.org/10.1152/japplphysiol.00852.2003

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Implication

Animal findings on pressure-evoked fMRI signals require validation before human use; leaves open extramedullary baroreflex mapping in conscious subjects.

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

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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