House of Mind

"Biology gives you a brain. Life turns it into a mind" - Jeffrey Eugenides

  • 26th July
    2011
  • 26
Acetylcholine The major source of acetylcholine in the brain is the pedunculopontine tegmental nucleus. The basal forebrain is another source one of cholinergic neurons (i.e. ACh neurons originate from the medial septum, diagonal band of Broca, nucleus basalis, and more).  The basal cholinergic forebrain is affected in neurodegenerative disorders like Alzheimer’s disease, Parkinson’s disease and dementia with Lewy bodies. Deficits in cholinergic neurotransmission have been associated with the neuropsychiatric effects present in some of these diseases.  Acetylcholine is synthesized from acetyl co-enzyme A and choline via choline acetyl transferase (CAT). Acetylcholine exerts its multiple effects via 2 receptors: muscarinic (mAChR) and nicotinic (nAChR) receptors. Both of these receptors are found pre- and postsynaptically in glutamatergic and gabaergic neurons.  nAChRs are ligand-gated ion channels that are divided into 2 subtypes depending on their distribution. Those that are found in the neuromuscular junction skeletal muscle are called nicotinic muscle (nM) while those that are found elsewhere within the nervous system are called nicotinic neuronal (nN).  mAChRs are G-protein coupled receptors that include 2 classes of receptors: M1-like and M2-like receptors. M1-like receptors activate phospholipase C and inhibit potassium currents. In contrast, M2-like receptors inhibit adenylyl cyclase and presynaptic calcium channels to activate potassium channels.  The action of acetylcholine is terminated via acetylcholinesterase which hydrolyzes it. Acetylcholine is one of the neurotransmitters that can also function as a neuromodulator. When it is not re-uptaked by the postsynaptic cell, it modulates synchronization of neural networks, among other things. ACh has a great number of physiologic effects including: enhancement of attention to sensory stimuli, improving sensory processing, encoding of memory for specific stimuli, modulation of cortical function and cognition, modulation of theta and gamma oscillations (during wakefulness and REM sleep), among others.  Sources:  Acetylcholine as a Neurotransmitter. 2004. Available at:  http://courses.washington.edu/chat543/cvans/sfp/acetylch.html Benarroch, Eduardo E. 2010. Acetylcholine in the cerebral cortex: Effects and clinical implications. Neurology. 75: 659-665. DOI: 10.1212/WNL.0b013e3181ee267e Hasselmo, Michael E. and Martin Sarter. 2011. Modes and Models of Forebrain Cholinergic Neuromodulation of Cognition. Neuropsychopharmacology. 36: 52-73. doi:10.1038/npp.2010.104

Acetylcholine

  • The major source of acetylcholine in the brain is the pedunculopontine tegmental nucleus. The basal forebrain is another source one of cholinergic neurons (i.e. ACh neurons originate from the medial septum, diagonal band of Broca, nucleus basalis, and more). 
  • The basal cholinergic forebrain is affected in neurodegenerative disorders like Alzheimer’s disease, Parkinson’s disease and dementia with Lewy bodies. Deficits in cholinergic neurotransmission have been associated with the neuropsychiatric effects present in some of these diseases. 
  • Acetylcholine is synthesized from acetyl co-enzyme A and choline via choline acetyl transferase (CAT).
  • Acetylcholine exerts its multiple effects via 2 receptors: muscarinic (mAChR) and nicotinic (nAChR) receptors. Both of these receptors are found pre- and postsynaptically in glutamatergic and gabaergic neurons. 
  • nAChRs are ligand-gated ion channels that are divided into 2 subtypes depending on their distribution. Those that are found in the neuromuscular junction skeletal muscle are called nicotinic muscle (nM) while those that are found elsewhere within the nervous system are called nicotinic neuronal (nN). 
  • mAChRs are G-protein coupled receptors that include 2 classes of receptors: M1-like and M2-like receptors. M1-like receptors activate phospholipase C and inhibit potassium currents. In contrast, M2-like receptors inhibit adenylyl cyclase and presynaptic calcium channels to activate potassium channels. 
  • The action of acetylcholine is terminated via acetylcholinesterase which hydrolyzes it.
  • Acetylcholine is one of the neurotransmitters that can also function as a neuromodulator. When it is not re-uptaked by the postsynaptic cell, it modulates synchronization of neural networks, among other things.
  • ACh has a great number of physiologic effects including: enhancement of attention to sensory stimuli, improving sensory processing, encoding of memory for specific stimuli, modulation of cortical function and cognition, modulation of theta and gamma oscillations (during wakefulness and REM sleep), among others. 

Sources: 

Acetylcholine as a Neurotransmitter. 2004. Available at: 

http://courses.washington.edu/chat543/cvans/sfp/acetylch.html

Benarroch, Eduardo E. 2010. Acetylcholine in the cerebral cortex: Effects and clinical implications. Neurology. 75: 659-665. DOI: 10.1212/WNL.0b013e3181ee267e

Hasselmo, Michael E. and Martin Sarter. 2011. Modes and Models of Forebrain Cholinergic Neuromodulation of Cognition. Neuropsychopharmacology. 36: 52-73. doi:10.1038/npp.2010.104