2c Neurotransmitters and Neuromodulators

• Neurotransmitters like glutamate and GABA play a crucial role in the transmission of neural information across a neural synapse to produce excitatory or inhibitory effects
• Neurons are categorized into sensory (afferent), motor (efferent), and interneurons that allow sensory and motor neurons to communicate in the Central Nervous System
• The pre-synaptic neuron holds the message, while the post-synaptic neuron is about to receive the message
• The neural synapse is where two neurons meet and transfer a message
• Neurotransmitters are chemicals released by the pre-synaptic neuron into the synaptic gap, traveling towards receptor sites on the dendrites of the post-synaptic neuron
• Excitatory neurotransmitters like glutamate increase the likelihood of the post-synaptic neuron firing, while inhibitory neurotransmitters like GABA decrease this likelihood
• Glutamate is the primary excitatory neurotransmitter in the Central Nervous System, involved in learning, memory formation, and neural plasticity
• GABA is the primary inhibitory neurotransmitter in the CNS, making post-synaptic neurons less likely to fire and associated with conditions like anxiety
• Neuromodulators are chemicals released by neurons to alter the effectiveness of neural transmission, influencing the reactivity of receptors to other neurotransmitters like Glutamate
• Neuromodulators do not release their chemical messengers into a single synapse but affect broader areas, influencing as many as 100,000 neurons at once
• Neuromodulators work more slowly than neurotransmitters, taking longer to establish effects and lasting longer, controlling brain states underlying behaviors like sleep and wakefulness
• Differences between Neurotransmitters and Neuromodulators:

  • Neurotransmitters are released by a pre-synaptic neuron to send signals to the post-synaptic neuron, while neuromodulators alter neural transmission by controlling the production and release of neurotransmitters
  • Neurotransmitters are released into the synaptic gap, while neuromodulators are released outside the synaptic gap affecting vast brain regions
  • Neurotransmitters target a single post-synaptic neuron, whereas neuromodulators target groups of neurons ranging from a few to thousands
  • Neurotransmitters act fast and are short-acting, while neuromodulators act slowly and last for longer periods
• Dopamine is a multifunctional neurotransmitter with excitatory and inhibitory effects, acting as a neuromodulator in the brain's reward pathway influencing feelings of pleasure, movement, attention, mood, cognition, and motivation
• Dopamine in the Substantia Nigra neural pathway in the midbrain carries messages for smooth muscle functioning; reduced dopamine levels due to damage lead to extreme muscle rigidity as in Parkinson's Disease
• Dopamine in thirst and drinking:

  • Dopamine carries reward signals along the brain's reward pathway, with the act of drinking itself releasing dopamine, not just the decrease in dehydration
• Dopamine in hunger and eating:

  • Hunger results from a decrease in baseline dopamine levels, triggering behaviors like seeking out and eating food; after eating, dopamine levels rise above baseline, leading to pleasure and reinforcing eating behavior
• How Dopamine leads to addiction:

  • Dopamine is involved in addiction behaviors like smoking, overeating, excessive alcohol consumption, and gambling, where more dopamine is required to experience the same pleasure, leading to addiction
• You can naturally increase dopamine levels by eating a diet rich in L-Tyrosine, found in foods like almonds, avocados, bananas, beef, chicken, and eggs, as well as taking turmeric, vitamin D, magnesium, and omega-3 supplements
• Neurotransmitters like glutamate can produce excitatory effects, while inhibitory effects are seen with neurotransmitters like gamma-aminobutyric acid (GABA)
• Neuromodulators like dopamine and serotonin have a range of effects on brain activity
• Serotonin acts as an inhibitory neurotransmitter and a neuromodulator, modulating behavioral processes including mood, perception, reward, anger, aggression, appetite, memory, sexuality, and attention
• Serotonin is produced in the brain stem and travels to the cerebrum, including the cerebral cortex, influencing brain activity in these areas
• Low levels of serotonin can disrupt the circadian rhythm of the sleep-wake cycle and the release of melatonin, leading to poor sleep, which is often a symptom of depression
• Research has shown that balanced serotonin levels lead to calm, focused, happy, attentive, and stable moods, while low serotonin levels are associated with depression and anxiety
• Low levels of serotonin in the brain, especially in the cerebral cortex, make people less likely to wait for a reward, increasing impulsive behaviors
• Low levels of serotonin affect communication between specific structures within the limbic system responsible for regulating emotions, leading to aggressive behaviors
• Tryptophan is the raw material for serotonin and is produced in the gut, so serotonin levels are lower when you haven't eaten
• Eating tryptophan-rich foods like poultry and chocolate can boost serotonin levels, potentially explaining why they are considered "feel-good" foods