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Sleep Breath 2004; 08(3): 147-154
DOI: 10.1055/s-2004-834485
ORIGINAL ARTICLE

Copyright © 2004 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA.

C-Fiber Activation Exacerbates Sleep-Disordered Breathing in Rats

D. W. Carley1 , 2 , 3 , S. Pavlovic2 , M. Malis2 , N. Knezevic2 , J. Saponjic1 , C. Li3 , M. Radulovacki2
  • 1Department of Medicine, University of Illinois at Chicago, Chicago Illinois
  • 2Department of Pharmacology, University of Illinois at Chicago, Chicago Illinois
  • 3Department of Bioengineering, University of Illinois at Chicago, Chicago Illinois
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Publication History

Publication Date:
24 September 2004 (online)

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We reported previously that activation of vagal feedback by protoveratrines or serotonin exacerbates sleep apnea in rats, but each of these agents activates multiple afferent fiber types. To elucidate the specific impact of C-fiber activity on sleep apnea, the present study utilized capsaicin (CAP), which stimulates C-fibers via the CAP receptor. Nine adult Sprague-Dawley rats were instrumented for chronic polysomnography and recorded for 6 hours on four occasions. Prior to each recording, the animals received an intraperitonea injection of either saline (control), or CAP 0.1, 1.0, or 10.0 mg/kg. Respiration was monitored by single-chamber plethysmography and apneas were scored as breaths longer than 2.5 seconds not preceded by a sigh. CAP increased apneas during non-rapid eye movement (NREM) sleep (p < 0.05 vs control) and reduced respiratory minute ventilation by about 15% in all behavioral states (waking, NREM, and REM sleep). We conclude that selective pharmacological activation of C-fibers produces a diathesis of sleep-disordered breathing specific to NREM sleep in rats.

KEYWORDS

Capsaicin - C-fibers - sleep apneas - rats

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David W CarleyPh.D. 

Section of Respiratory and Critical Care Medicine, Department of Medicine, MC 787

840 South Wood St.

Chicago, IL 60612

Email: DWCarley@uic.edu