“…Also, there is a functional correlation among the midbrain dopaminergic neurons and the hippocampus, whose stimulation causes the improvement of LTP and learning (Zarrindast et al, 2012[ 89 ]). The NAC involved in passive avoidance learning and morphine state-dependent learning, too (Noorbakhshnia and Zarrinimehr, 2019[ 48 ]). Reports are suggesting a probable role for the dopaminergic (Azizbeigi et al, 2011[ 5 ]), and NO (Zarrindast et al, 2012[ 89 ]) systems of the NAC in the improving role of nicotine on the morphine-produced memory-impairment as well as morphine state-dependent memory (Zarrindast et al, 2012[ 89 ]).…”