NEUROTRANSMITTERS OF NS

The nervous system (NS) uses various neurotransmitters (Acetylcholine, Dopamine, Serotonin, Glutamate, Gamma­aminobutyric acid, Norepinephrine, Endorphins) to transmit signals between neurons and other cells.

A brief information on the grouping of neurotransmit­ters based on their precursors and functions is provided in Table 8.3.

1. Neurotransmitters of PNS include Acetylcholine, Norepinephrine (noradrenaline), Epinephrine (adrenaline), Dopamine, and Serotonin.

2. Neurotransmitters of CNS include Glutamate, GABA, Acetylcholine, Dopamine, Serotonin, Norepinephrine, Histamine, Endorphins, and Enkephalins.

1. Excitatory neurotransmitters: Excitatory neu­rotransmitters are neurotransmitters that promote the generation of action potentials in postsynap- tic neurons, thereby increasing neuronal activity. The most common and abundant excitatory neu­rotransmitter in the central nervous system is glu­tamate. When glutamate binds to its receptors on

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TABLE 8.3

Grouping of Neurotransmitters Based on their Precursors

Principles of Veterinary Animal Physio

the postsynaptic neuron, it triggers depolarization of the neuron, leading to an action potential.

2. Inhibitory neurotransmitters: Inhibitory neu­rotransmitters are neurotransmitters that decrease the likelihood of a postsynaptic neuron firing an action potential, thereby reducing neuronal activ­ity. The primary inhibitory neurotransmitter in the central nervous system is gamma-aminobutyric acid (GABA). When GABA binds to its receptors on the postsynaptic neuron, it typically increases the flow of negatively charged ions into the neu­ron, hyperpolarizing it and inhibiting the genera­tion of an action potential.

Another important inhibitory neurotransmitter in the cen­tral nervous system is glycine. Like GABA, glycine also hyperpolarizes the postsynaptic neuron by increasing the flow of negatively charged ions into the neuron.

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