since the wildtype and knockout mice responded for nicotine at a similar maximal rate. Instead, deficient α5* nAChR signaling appears to attenuate the negative effects of nicotine that limit its intake (i.e., descending portion of dose-response curve). These findings are highly consistent with the increased vulnerability to tobacco addiction in human smokers carrying CHRNA5 risk alleles that result in less functional α5* nAChRs12,13.
