A<unk>  receptor agonist is an agent that enhances the activity of the<unk>  acetylcholine receptor. The<unk>  receptor has different subtypes, labelled M1-M5, allowing for further differentiation.
In the form of pilocarpine<unk>  receptor agonists have been used medically for a long time.
M1-type<unk>  acetylcholine receptors  play a role in cognitive processing.  In Alzheimer disease (AD) amyloid formation may decrease the ability of these receptors to transmit their signals leading to decrease cholinergic activity. As these receptors themselves appear relatively unchanged in the disease process, they have become a potential therapeutic target  when trying to improve cognitive function in patients with AD.
A number of<unk> s have been developed and are under investigation to treat AD. These agents show promise as they are neurotrophic, decrease amyloid depositions, and improve damage due to oxidative stress. Tau-phosphorylation is decreased and   cholinergic function enhanced.  Notably several agents of the AF series of<unk> s have become the focus of such research:. AF102B, AF150(S), AF267B. In animal models that are mimicking the damage of AD, these agents appear promising.
Muscarinic agonist
Muscarinic antagonist
Alpha-adrenergic agonist
Beta-adrenergic agonist
Adrenergic agonist
H₂-receptor antagonist
Ganglionic blocker
Serotonin antagonist