Fentanyl effects on breath generation in C57BL/6J and A/J mouse strains

Abstract We examined the effect of fentanyl on chemoresponsiveness in mouse strains divergent in the expression of spontaneous and post-hypoxic pauses. Frequency and tidal volume were recorded with plethysmography in A/J and C57BL/6J (B6) male mice. Mice selected at random received an intraperitoneal (IP) injection of either saline, low dose fentanyl (LDF = 0.04 mg/kg), or high dose fentanyl (HDF = 0.4 mg/kg) under hypoxia (8% O 2 ) or hyperoxia (100%O 2 ). LDF produced a decrease in frequency during hypoxia in B6, but not A/J, mice. HDF significantly decreased frequency and tidal volume in both strains under hypoxia and hyperoxia ( p