Neurotransmitters (NT)

Neurotransmitters (NT)

Definition: Neurotransmitters (NT) are chemical messengers that transmit signals across synapses from one neuron to another or from neurons to muscles and glands. They play a crucial role in communication within the nervous system, influencing a wide range of physiological functions, including mood, muscle movement, and heart rate.

Types of Neurotransmitters

Excitatory Neurotransmitters: These neurotransmitters increase the likelihood of the receiving neuron firing an action potential. Examples include:

• Glutamate: The primary excitatory neurotransmitter in the central nervous system.
• Norepinephrine (Noradrenaline): Involved in arousal and alertness.

Inhibitory Neurotransmitters: These decrease the chances of the receiving neuron firing an action potential. Key examples include:

• Gamma-Aminobutyric Acid (GABA): The main inhibitory neurotransmitter in the brain.
• Glycine: Primarily found in the spinal cord.

Modulatory Neurotransmitters: These can affect multiple neurons simultaneously and regulate various functions. Notable examples include:

• Dopamine: Involved in reward, motivation, and motor control.
• Serotonin: Influences mood, appetite, and sleep.

Mechanism of Action

Neurotransmitters are synthesized in neurons and stored in vesicles at the presynaptic terminal. When an electrical impulse reaches this terminal, neurotransmitters are released into the synaptic cleft. They then bind to specific receptors on the postsynaptic neuron, leading to excitatory or inhibitory effects depending on the type of neurotransmitter and receptor involved.

Key Steps in Neurotransmission:

1. Synthesis: Neurotransmitters are produced from precursor molecules within the neuron.
2. Release: Upon activation, neurotransmitters are released into the synaptic cleft.
3. Binding: They bind to receptors on the postsynaptic membrane, causing a response.
4. Termination: The action of neurotransmitters is terminated by reuptake into the presynaptic neuron or enzymatic degradation.

Clinical Implications

Neurotransmitter Disorders: Imbalances or dysfunctions in neurotransmitter systems can lead to various neurological and psychiatric disorders, including:

• Depression: Often associated with low levels of serotonin and norepinephrine.
• Parkinson’s Disease: Characterized by a deficiency of dopamine.
• Anxiety Disorders: Linked to imbalances in GABA and serotonin levels.

Therapeutic Approaches: Treatments targeting neurotransmitter systems include:

• Antidepressants: Often aim to increase serotonin or norepinephrine levels.
• Antipsychotics: Typically work by modulating dopamine pathways.

Conclusion

Neurotransmitters are vital for effective communication within the nervous system, influencing numerous bodily functions and behaviors. Understanding their roles can help inform treatments for various neurological and psychological conditions.

References

• BYJU’S – Neurotransmitter
• Queensland Brain Institute – What are neurotransmitters?
• Wikipedia – Neurotransmitter
• Kenhub – Neurotransmitters: Types, functions and disorders
• Britannica – Neurotransmitter | Definition, Signaling, & Types
• Medical News Today – Neurotransmitters: What they are, functions, and psychology