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Activity patterns of cardiac vagal motoneurons in rat nucleus ambiguus.
- Source :
- American Journal of Physiology: Regulatory, Integrative & Comparative Physiology; Dec2002, Vol. 52 Issue 6, pR1327, 8p, 1 Diagram, 20 Graphs
- Publication Year :
- 2002
-
Abstract
- Extracellular recordings were made in the right nucleus ambiguus of urethane-anesthetized rats from 33 neurons that were activated at constant latency from the craniovagal cardiac branch. Their calculated conduction velocities were in the B-fiber range (1.6-13.8 m/s, median 4.2), and most (22/33) were silent. Active units were confirmed as cardiac vagal motoneurons (CVM) by the collision test for antidromic activation and by the presence of cardiac rhythmicity in their resting discharge (9/9). Brief arterial pressure rises of 20-50 mmHg increased the activity in five of five CVM by 0.1 ± 0.02 spikes·s[sup -1]·mmHg[sup -1] from a resting 3.8 ± 1.2 spikes/s; they also recruited activity in two of four previously silent cardiac branch-projecting neurons. CVM firing was modulated by the central respiratory cycle, showing peak activity during inspiration (8/8). Rat CVM thus show firing properties similar to those in other species, but their respiratory pattern is distinct. These findings are discussed in relation to mechanisms of respiratory sinus arrhythmia. [ABSTRACT FROM AUTHOR]
- Subjects :
- MOTOR neurons
CIRCADIAN rhythms
BLOOD pressure
Subjects
Details
- Language :
- English
- ISSN :
- 03636119
- Volume :
- 52
- Issue :
- 6
- Database :
- Complementary Index
- Journal :
- American Journal of Physiology: Regulatory, Integrative & Comparative Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 8662892
- Full Text :
- https://doi.org/10.1152/ajpregu.00271.2002