Early-in-life bladder inflammation alters U50,488H but not morphine-induced inhibition of visceromotor responses to urinary bladder distension

► Morphine (i.v.) produced dose-dependent inhibition of the VMR to UBD in all groups. ► U50,488H (i.v.) produced dose-dependent inhibition of the VMR in most groups. ► Bladder inflammation both EIL and as adults augmented VMRs after 1 mg/kg U50,488H. ► The same group demonstrated diminished inhibition of VMRs after 4 mg/kg U50,488H. ► A decrease in inhibition by κ-opioids could contribute to bladder pain states.