Neuroscience 2004 Abstract
| Presentation Number: | 539.2 |
|---|---|
| Abstract Title: | Developmental neural patterns of the baroreceptor reflex assessed with functional magnetic resonance imaging. |
| Authors: |
Henderson, L. A.*1
; Richard, C. A.2
; Macey, P. M.2
; Runquist, M. L.3
; Harper, R. M.2
1Anat. and Histology, Univ. of Sydney, Sydney, Australia 2CA, NSW 2006, 2006, 3USA, NSW 2006, 2006, |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Cardiovascular regulation |
| Session: |
539. Cardiovascular Regulation: Integrated Responses Poster |
| Presentation Time: | Monday, October 25, 2004 2:00 PM-3:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # CC13 |
| Keywords: | BLOOD PRESSURE, CARDIOVASCULAR, DEVELOPMENT, CAT |
The baroreceptor reflex is not fully developed at birth. Hypotensive challenges in the adult cat elicit functional magnetic resonance imaging (fMRI) signal intensity declines in multiple medullary, cerebellar, insular and pontine regions, and signal increases in amygdala and hypothalamic areas. We used fMRI procedures to compare responses in neural sites involved in mediating the baroreceptor reflex in kittens with adult cats, and thus determine mechanisms underlying the incomplete baroreceptor responses in developing animals. A baroreceptor reflex was elicited in isofluorane-anaesthetized adult cats (n=7) and kittens (n=14; 14-25 days old) via i.v. sodium nitroprusside. FMRI image series were collected during 60 s baseline and 180 s challenge periods. Significant differences between signal intensity changes in adult cats and kittens were assessed on a voxel-by-voxel basis using SPM2, and by volume-of-interest analysis. Baseline arterial pressure increased and heart rate decreased with age, while baroreceptor reflex sensitivity initially increased and then declined to near-adult levels by 25 days. In contrast to declines in adult cats, signals increased in kittens in the dorsal and ventrolateral medulla during the hypotensive challenges. Significant differences emerged in cerebellar cortex and deep nuclei, dorsolateral pons, midbrain tectum, hippocampus, thalamus and insular cortex. The altered neural responses in medullary baroreceptor reflex sites may have resulted from disinhibitory or facilitatory influences from cerebellar and more rostral structures as a result of inadequately-developed myelination or other neural processes. A comparable immaturity of blood pressure control mechanisms in humans would have significant clinical implications.
Supported by HL-22418
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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