Table 1.

Summary of the role of cholinergic receptors in the brain. The role of the cholinergic receptors such as nicotinic (nAchRs) or muscarinic (mAchRs) receptors in different brain regions of animal models is summarized.

Description	Outcomes	References
α7 nAchRs	Enhancement of LTP in the hippocampus and in the amygdala	[46,47]
3xTg-AD mouse model	Reduction in α7 nAchRs levels in an age-dependent manner	[49]
Blockade of mAchR signaling by an antagonist in rats	Impairment in the acquisition and consolidation of contextual fear conditioning	[51]
Muscarinic agonist against M1 mAchRs in a 3xTg-AD mouse model	Decrease in β-amyloid plaques accumulation, decrease in tau hyperphosphorylation, improvement in cholinergic activity in the cortex and the hippocampus and improved some cognitive functions	[54]
Knockout of M1 and M4 mAchRs in mice	Impacted hippocampal circuitry and hippocampal release of Ach	[57,58]
Lack of M1 AchR in mouse PFC	Impairment of cholinergic signaling in pyramidal neurons and cue detection deficits	[59]
M2 AchR knockout mice	Deficit in specific learning and memory tests	[62]