Activity patterns of cardiac vagal motoneurons in rat nucleus ambiguus
In: American journal of physiology. Regulatory, integrative and comparative physiology, Jg. 283 (2002-10-22), Heft 6
Online
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Zugriff:
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−1 · mmHg−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.
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Activity patterns of cardiac vagal motoneurons in rat nucleus ambiguus
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Autor/in / Beteiligte Person: | Quintin, Luc ; Jean Marc Pequignot ; McAllen, Robin M. ; Trevaks, David ; Cividjian, Andrei ; Rentero, Nicolas |
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Zeitschrift: | American journal of physiology. Regulatory, integrative and comparative physiology, Jg. 283 (2002-10-22), Heft 6 |
Veröffentlichung: | 2002 |
Medientyp: | unknown |
ISSN: | 0363-6119 (print) |
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