State-dependent alteration of respiratory cycle timing by stimulation of the central nucleus of the amygdala
Harper RM, Frysinger RC, Trelease RB, and Marks JD (1984) State-dependent alteration of respiratory cycle timing by stimulation of the central nucleus of the amygdala. Brain Res 306:1-2 1–8.
Abstract: The effect of electrical stimulation of the amygdaloid central nucleus (ACE) on respiration was studied in unanesthetized, unrestrained cats during sleep-waking states. Single 0.5-ms 500-microA constant-current pulses delivered to the ACE at various points on the respiratory cycle, produced a transient inspiratory effort which summated with ongoing inspiratory activity and reduced inspiratory time. Stimulus pulses delivered during the expiratory phase resulted in an earlier shift to inspiration. Repetitive single pulse stimuli delivered to the ACE at a rate slightly faster than the spontaneous respiratory cycle during the alert state, were capable of 'entraining' respiration at the stimulus frequency. This entrainment disappeared in quiet sleep. Atropine, however, which produced synchronous high voltage slow waves and 12-14-Hz EEG spindle activity in the alert cat, did not impair this entrainment. Short (300-500 ms) 100-Hz trains of 0.5-ms pulses to the ACE produced rapid onset, sustained inspiration and a rise in blood pressure in the alert animal. During quiet sleep the response was attenuated but qualitatively similar, and also aroused the animal. Single pulse stimuli, however, were not associated with cardiovascular changes or generalized arousal. These results suggest that the ACE contributes to excitation of the inspiratory cycle, possibly through the large projection of this nucleus to the parabrachial pons.
Keywords: amygdala, respiration, stimulation, central nucleus, forebrain, brain stem, sleep, waking
Context
- Direct physiologic assessment of the contribution of the amygdala to respiratory cycle timing by electrical stimulation of the central nucleus in freely behaving cats. Stimulation suring inspiration increased inspiratory activity, while stimulation during expiration led to earlier inspiration. Respiration could be entrained to a frequency slightly above the spontaneous one in awake animals but not while sleeping.