Neurotransmitters PDF

1 Neurotransmitters Chemical messengers called neurotransmitters carry neural signals from one neuron to another. They can also carry the signal from one neuron to an effector, such as a gland or muscle fibre. Neurotransmitters are produced by some glands, such as t...

1 Neurotransmitters Chemical messengers called neurotransmitters carry neural signals from one neuron to another. They can also carry the signal from one neuron to an effector, such as a gland or muscle fibre. Neurotransmitters are produced by some glands, such as the pituitary and adrenal glands. 2 Neurotransmitters Different types of cells secrete different neurotransmitters. Each chemical in the brain works in specific locations and may have a different effect according to where it is activated. Most major neurotransmitters are made from amino acids. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron. 3 Neurotransmitters A neurotransmitter may have an excitatory effect on the postsynaptic membrane, resulting in the receptor proteins triggering ion channels to open and allow positive ions (ie. sodium) to flow into the postsynaptic neuron. In this case, membranes become slightly depolarized and lowers its threshold level. 4 Neurotransmitters A neurotransmitter may have an inhibitory effect on the postsynaptic membrane, resulting in the receptor proteins triggering potassium channels to open, and potassium ions to flow out. This results in hyperpolarization. After neurotransmitters have had their effect, they are broken down by enzymes to be reabsorbed by the presynaptic cell. 5 Neurotransmitter Excitatory or General Function Levels too high? Levels too low? Inhibitory? 6 acetylcholine Both (mostly Enables contraction of muscle fibres; Critical muscles (ie. heart, -Muscles weakness excitatory) also played a role in learning and diaphragm) enter state of -Memory, focus, and thinking memory. constant contraction/paralysis. issues noradrenaline Excitatory Complements the actions of -High blood pressure -Hunger cravings epinephrine (hormone) which prepares -Anxiety -Exhaustion body to respond to danger/stress; -Insomnia involved in alertness. glutamate Excitatory Involved in memory, as well as thinking -Brain overstimulation -Low energy/concentration and learning. -Migraines, seizures -Learning/memory issues -Cell death -Mental exhaustion GABA Inhibitory Regulates brain activity and mood, -Daytime sleepiness -Mood disorders producing a calming effect. -Shallow breathing -Anxiety, depression -Difficulty concentrating -Seizures dopamine Both Affects synapses in the control of body Schizophrenia (distorted Parkinson’s Disease (destroys movement; also linked to sensations of perception of reality) neurons; causes tumours, pleasure, ie. eating (“Rewards slurred speech, coordination System”). issues) serotonin Inhibitory Regulates temperature and sensory -Nervousness, insomnia -Depression perception; also involved in mood -Nausea, diarrhea -Chronic pain control. -Agitation, sweating -Restlessness