Neurotransmitters

• Neurotransmitters are chemical messengers that play a crucial role in transmitting signals between neurons in the nervous system.

• They are released by the presynaptic neuron at a synapse, diffuse across the synaptic cleft, and bind to specific receptors on the postsynaptic neuron.

• This binding can either excite or inhibit the postsynaptic neuron, influencing the likelihood of generating an action potential.

Neurotransmitters

1. Amino acids:

• These are the most common neurotransmitters in the central nervous system (CNS). Examples include:

  • Glutamate: The primary excitatory neurotransmitter in the CNS, involved in learning and memory.

  • Gamma-aminobutyric acid (GABA): The primary inhibitory neurotransmitter in the CNS, involved in reducing neuronal excitability.

  • Glycine: An inhibitory neurotransmitter found mainly in the spinal cord and brainstem.

2. Monoamines:

• Derived from single amino acids, these neurotransmitters include:

  • Dopamine: Involved in the regulation of movement, reward, motivation, and cognition.

  • Norepinephrine (noradrenaline): Involved in the regulation of attention, alertness, and the fight-or-flight response.

  • Serotonin: Involved in mood regulation, appetite, sleep, and cognitive functions such as learning and memory.

  • Histamine: Involved in the regulation of arousal, wakefulness, and inflammatory responses.

3. Neuropeptides:

• These are short chains of amino acids that act as neurotransmitters or neuromodulators, regulating neuronal activity. Examples include:

  • Endorphins: Involved in pain relief and the regulation of emotions.

  • Substance P: Involved in pain transmission and inflammation.

  • Oxytocin: Involved in social bonding, childbirth, and lactation.

4. Acetylcholine:

• Found in both the central and peripheral nervous systems.

• Functions: Involved in muscle movement, memory, and the regulation of autonomic functions such as heart rate and digestion.

5. Purines:

• Involved in energy metabolism and cellular signaling.

• Examples:

  A.  Adenosine: Involved in energy metabolism.

  B.  ATP (Adenosine Triphosphate): Involved in cellular signaling..

6. Gasotransmitters:

• Small gaseous molecules that can act as neurotransmitters.

• Example:

  • Nitric Oxide (NO): Plays a role in vasodilation and synaptic plasticity.