The Cholonergic System Flashcards
Where is this found?
in the periphery - acetylcholine at neuromuscular junction and synapses in the autonomy ganglia
in the brain - basal forebrain complex, projections to hippocampus and cortex
What is the pontomesencephalotegmental complex?
Cholinergic link between the brain stem and the Baal forebrain complex
What are cholinergic interneurons?
Messes with other neurons near by and modulates their activity
each interneuron innervates 1000’s of local principle neurons and modulates activity
How is acetylcholine synthesised?
It is made from choline - amount of choline is the rate limited step
How is it metabolised?
Rapidly degraded in synaptic clef but acetylcholinesterase - choline is transported back into the presynaptic terminal and coverted to acetylcholine
How is acetylcholinesterase made?
By the cholinergic neuron, secreted into synaptic cleft
What drugs affect the release, storage and degradation?
Acetylcholinesterase inhibitors - block the breakdown of ACh thus prolonging its action in the synaptic cleft. for example, physostigmine - treats alzeimers (the cognitive decline) and myasthenia gravis
What is myasthenia gravis?
Autoimmune disorders - where AchR is destroyed - get a droopy eye, characterised by muscle weakness
What is acetylcholine?
Causes muscles to contract, activates pain responses and regulates endocrine and REM sleep functions
What drugs affect the vesicle docking and release?
Botulinum and tetanus toxins - blocks the docking of vesicles by attacking SNARE’s - no release. Tetaus toxins is transported and works inhibitory on cholinergic motor neurons of spinal cord - they constantly fire, resulting in permanent muscle contraction, lock jaw
Botox acts directly at synapse in metro-muscular junction - the muscles lose all input so become relaxed
What are the disorders of the cholinergic system?
Peripheral - myasthenia gravis (destroys cholinergic receptos in the muscle, muscle weakness)
Brain - alzeimers (loss of cholinergic neurons in basic ganglia)
Addition - nicotine
Epilepsy - mutations in nicotinic receptor genes
Schizophrenia
