ANS Neurotransmitters and Receptors
ANS neurons are classified as either Cholinergic or Adrenergic based upon the neurotransmitter they produce and release. The receptors for these NTs are integral membrane proteins located in the plasma membrane of the postsynaptic neuron or effector cell.
1) Cholinergic Neurons and Receptors
These neurons release the NT Acetylcholine (ACh). In the ANS, these include:
All the sympathetic and parasympathetic preganglionic neurons Sympathetic postganglionic neurons that innervate sweat glands (human) All the parasympathetic postganglionic neurons
ACh is stored in synaptic vesicles and released by exocytosis where is diffuses across the cleft and binds with specific Cholinergic Receptors .
There are 2 types: Nicotinic & Muscarinic
Nicotinic Receptors : present in the plasma membrane of dendrites and cell bodies of both sympathetic and parasympathetic postganglionic neurons, the chromaffin cells in the adrenal medullae, and the motor end plate at the neuromuscular junction. These receptors get their name because nicotine mimics ACh by binding to these receptors.
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