Dementia of the Alzheimer type is characterized by accumulation of senile plaques and neurofibrillary tangles, and loss of cortical neurons, especially cholinergic neurons. Current therapies aim to improve cholinergic transmission using acetylcholinesterase inhibitors like donepezil, galantamine, and rivastigmine, or prevent excitotoxicity using the NMDA receptor antagonist Memantine. Acetylcholinesterase inhibitors are used to improve cholinergic transmission that is reduced due to loss of cholinergic neurons, while Memantine blocks excess calcium entry into neurons through the NMDA receptor that can lead to neurodegeneration.

2. • Dementia of the Alzheimer type has three distinguishing features
• 1 accumulation of senile plaques (β-amyloid accumulations),
• 2 formation of numerous neurofibrillary tangles, and
• 3 loss of cortical neurons, particularly cholinergic neurons.

3. Current therapies aim to either
1. improve cholinergic transmission within the CNS or
2. prevent excitotoxic actions resulting from overstimulation of NMDA-
glutamate receptors in selected areas of the brain.

4. Acetylcholinesterase inhibitors
• progressive loss of cholinergic neurons and, presumably, cholinergic transmission
within the cortex to the memory loss that is a hallmark symptom of Alzheimer
disease.
• it is postulated that inhibition of acetylcholinesterase (AChE) within the CNS
improves cholinergic transmission
• AChE inhibitors approved for the treatment of Alzheimer disease include
donepezil , galantamine , and rivastigmine .

5. NMDA receptor antagonist
• glutamate receptors in the CNS appears to be critical for the formation of
certain memories.
• overstimulation of glutamate receptors, particularly of the NMDA type, may
result in excitotoxic effects on neurons and suggested as a mechanism for
neurodegenerative or apoptotic (programmed cell death) processes

6. • Binding of glutamate to the NMDA receptor assists in the opening of an ion
channel that allows Ca2+ to enter the neuron.
• Excess intracellular Ca2+ can activate a number of processes that ultimately
damage neurons and lead to apoptosis.
• Memantine is an NMDA receptor antagonist

7. Thank you for reading ..