Skip to main content
. Author manuscript; available in PMC: 2016 Jun 1.
Published in final edited form as: Anesthesiology. 2015 Jun;122(6):1288–1298. doi: 10.1097/ALN.0000000000000628

Figure 3.

Figure 3

Protocol 2. A: Phrenic neurogram (PNG, in arbitrary units) of a young rabbit (13d, 160g). Intravenous (IV) remifentanil depressed both peak phrenic amplitude and respiratory rate. Naloxone microinjection into the bilateral preBötzinger Complex (preBC) partially reversed the respiratory depression in this animal. IV naloxone achieved complete reversal of the remifentanil effect. B–D: Effects of intravenous remifentanil infusion (IV REMI), localized microinjection of the opioid antagonist naloxone (local NAL, 1mM) into the bilateral preBötzinger Complex and reversal of residual opioid effects with intravenous bolus of naloxone (IV NAL). Pooled data are shown separately for 16 adult (blue) and 14 young (red) rabbits. Box plots show median and range (10%, 25%, 75%, 90%); individual data points are superimposed. Levels of significance reflect the results of the 2-way analysis of variance. B: Local naloxone did not affect respiratory rate. C: Local naloxone did not affect respiratory drive, calculated as PPA/Ti. D: Local naloxone partially reversed the decrease in Ti/Ttotal. The effects in young and adult animals were not significantly different. n.s. = not significant; PPA = peak phrenic activity; Ti = inspiratory duration; Ttotal = duration of the respiratory cycle.