Effects of α2-adorenoceptor agonist dexmedetomidine on respiratory rhythm generation of newborn rats

Dexmedetomidine-mediated neuroprotection against sevoflurane-induced neurotoxicity extends to several brain regions in neonatal rats

“…50 We found that administration of DEX alone, at doses of 25 mg kg À1 and above, caused minor decreases in respiratory rate and small alterations in blood gas parameters. These results are consistent with previous reports showing a small decrease in respiratory rhythm generation in vitro in newborn rats 58 and with mild effects on respiratory rate in dogs treated with DEX alone or in combination with isoflurane. 59 Our results are also consistent with the absence of adverse effects on respiratory rate and blood gas parameters in patients treated with DEX post-surgery in the ICU.…”

Imidazoline 1 receptor activation preserves respiratory drive in spontaneously breathing newborn rats during dexmedetomidine administration

“…Although our present observation is limited in newborn rats, a recent study using a newborn rat brainstem–spinal cord preparation has shown that the administration of dexmedetomidine + atipamezole affects respiration indices in a manner consistent with the change in f R observed in our previous study , although in these experiments and present study a possible influence of isoflurane anesthesia for preparation cannot be excluded from the results. Therefore, further investigations are needed into the relationship between our observations regarding respiratory drive and timing and the involvement of the central mechanisms related to α 2 ‐adrenoceptor and I 1 receptor.…”

“…In addition, we found that the administration of atipamezole, a selective α 2 ‐adrenoceptor antagonist, completely (in the case of f R and therefore ) or partially (in the case of HR) ameliorated the dexmedetomidine‐associated reduction of these cardiorespiratory indices . The results were compatible with earlier observations, which showed that atipamezole can reverse suppressive effect of dexmedetomidine on blood pressure and HR in human volunteers and respiratory rhythm in newborn rat brainstem–spinal cord preparation .…”

Effect of dexmedetomidine on cardiorespiratory regulation in spontaneously breathing adult rats

“…been seen in a newborn rat in vitro brainstem-spinal cord preparation [19], suggesting that dexmedetomidine affects the generation of respiratory rhythm at the level of the brainstem and spinal cord. Furthermore, from a comparison of the results of dexmedetomidine plus atipamezole with those of dexmedetomidine plus efaroxan (the latter being an α 2 -adrenoceptor/I 1 receptor antagonist), we hypothesized that I 1 receptor stimulation due to dexmedetomidine was a factor involved in maintaining V T /T I (an index of respiratory drive) in newborn rats [11].…”