User:Camiladavila17/Retrograde signaling

The most prevalent endogenous retrograde neurotransmitters are nitric oxide[21][22] and various endocannabinoids, which are lipophilic ligands [26].

The retrograde neurotransmitter, nitric oxide (NO) is a soluble gas that can readily diffuse through various cell membranes. Nitric oxide synthase is the enzyme responsible for the synthesis of NO in various presynaptic cells [6]. Specifically, NO is known to play a critical role in the long-term potentiation (LTP), which plays an important role in memory storage within the hippocampus. Additionally, literature suggests that NO can act as intracellular messengers in the brain and can also have an effect on the presynaptic glutamatergic and GABAergic synapses.

Utilizing retrograde signaling, endocannabinoids, a type of retrograde neurotransmitter, are activated when they bind to G-protein coupled receptors on the presynaptic terminals of neurons. The activation of endocannabinoids results in the release of particular neurotransmitters at the excitatory and inhibitory synapses of a neuron, ultimately impacting various forms of plasticity.

In contrast to conventional (anterograde) neurotransmitters, retrograde neurotransmitters are synthesized in the postsynaptic neuron, and bind to receptors on the axon terminal of the presynaptic neuron[4]. Additionally, retrograde signaling initiates a signaling cascade that focuses on the presynaptic neuron. Once retrograde signaling is initiated, there is an increase in action potentials that begin in the presynaptic neuron, which directly impacts the postsynaptic neuron by increasing the number of its receptors.