title: Respiratory pattern in awake rats: effects of motor activity and of alerting stimuli.
abstract: Our aim was to assess the impact of motor activity and of arousing stimuli on respiratory rate in the awake rats. The study was performed in male adult Sprague-Dawley (SD, n=5) and Hooded Wistar (HW, n=5) rats instrumented for ECG telemetry. Respiratory rate was recorded using whole-body plethysmograph, with a piezoelectric sensor attached for the simultaneous assessment of motor activity. All motor activity was found to be associated with an immediate increase in respiratory rate that remained elevated for the whole duration of movement; this was reflected by: i) bimodal distribution of respiratory intervals (modes for slow peak: 336+/-19 and 532+/-80 ms for HW and SD, p<0.05; modes for fast peak 128+/-6 and 132+/-7 ms for HW and SD, NS); and ii) a tight correlation between total movement time and total time of tachypnoea, with an R(2) ranging 0.96-0.99 (n=10, p<0001). The extent of motor-related tachypnoea was significantly correlated with the intensity of associated movement. Mild alerting stimuli produced stereotyped tachypnoeic responses, without affecting heart rate: tapping the chamber raised respiratory rate from 117+/-7 to 430+/-15 cpm; sudden side move--from 134+/-13 to 487+/-16 cpm, and turning on lights--from 136+/-12 to 507+/-14 cpm (n=10; p<0.01 for all; no inter-strain differences). We conclude that: i) sniffing is an integral part of the generalized arousal response and does not depend on the modality of sensory stimuli; ii) tachypnoea is a sensitive index of arousal; and iii) respiratory rate is tightly correlated with motor activity.
authors.affiliation: School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, SA5000, Australia.
authors.forename: Muammar M
authors.initials: MM
authors.lastname: Kabir
authors.forename: Mirza I
authors.initials: MI
authors.lastname: Beig
authors.forename: Mathias
authors.initials: M
authors.lastname: Baumert
authors.forename: Mimosa
authors.initials: M
authors.lastname: Trombini
authors.forename: Francesca
authors.initials: F
authors.lastname: Mastorci
authors.forename: Andrea
authors.initials: A
authors.lastname: Sgoifo
authors.forename: Frederick R
authors.initials: FR
authors.lastname: Walker
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Day
authors.forename: Eugene
authors.initials: E
authors.lastname: Nalivaiko
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001143:Arousal / Q000502:physiology*; D005106:Exploratory Behavior; D008297:Male; D008991:Monitoring, Physiologic / Q000662:veterinary; D009043:Motor Activity / Q000502:physiology*; D010993:Plethysmography, Whole Body / Q000662:veterinary; D012123:Pulmonary Ventilation / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012016:Reference Values; D056152:Respiratory Rate / Q000502:physiology*; D013045:Species Specificity