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 2.

Figure 2

Protocol 1. A: Phrenic neurogram of a young rabbit (20d, 325g). Bilateral [D-Ala2,N-Me-Phe4,Gly-ol]-enkephalin (DAMGO) microinjection (70 nl) into the preBötzinger Complex plus 1 mm rostral and 1 mm caudal to this area depressed peak phrenic amplitude and respiratory rate to the point of apnea. Local injection of naloxone (NAL) at the same coordinates reversed the DAMGO effect. B–D: Effects of localized microinjection of the μ-opioid agonist DAMGO in pharmacological concentrations (100 μM) into the bilateral preBötzinger Complex and reversal with localized injection of the opioid antagonist naloxone (1mM). Pooled data are shown separately for 16 adult (blue) and 8 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: DAMGO injection depressed respiratory rate. C: Respiratory drive, calculated as PPA/Ti, was not affected. D: DAMGO injection depressed inspiratory fraction (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.