please summarize the following in bullet points: Substances That Are Neurotransmitters or Neuromodulators Substance Location Effect Clinical Example Acetylcholine Many parts of the... please summarize the following in bullet points: Substances That Are Neurotransmitters or Neuromodulators Substance Location Effect Clinical Example Acetylcholine Many parts of the brain, spinal cord, neuromuscular junction of skeletal muscle, and many ANS synapses Excitatory or inhibitory Alzheimer disease (a type of dementia) is associated with a decrease in the number of acetylcholine-secreting neurons. Muscle weakness caused by myasthenia gravis results from an autoimmune response to acetylcholine receptors on the postsynaptic terminal. Monoamines Norepinephrine Many areas of the brain and spinal cord; also in some ANS synapses Excitatory or inhibitory CNS: Sleep-wake cycles and mood. Cocaine and amphetaminesa result in overstimulation of postsynaptic neurons. PNS: Sympathetic nerve transmission. Serotonin Many areas of the brain and spinal cord Generally inhibitory Is involved with mood, anxiety, and sleep induction. Levels of serotonin are elevated in schizophrenia (delusions, hallucinations, withdrawal). Dopamine Some areas of the brain and ANS synapses Generally excitatory Parkinson disease (depression of voluntary motor control) results from destruction of dopamine-secreting neurons. Drugs used to increase dopamine can induce vomiting and hallucinations. Histamine Posterior hypothalamus Excitatory (H1 and H2 receptors) and inhibitory (H3 receptors) There is no clear indication of histamine-associated pathologic conditions. Histamine is involved with arousal and attention and links to other brain transmitter systems. Amino Acids Gamma-aminobutyric acid (GABA) Most neurons of the CNS have GABA receptors Majority of postsynaptic inhibition in the brain Drugs that increase GABA function have been used to treat epilepsy by inhibiting excessive discharge of neurons. Glycine Spinal cord Most postsynaptic inhibition in the spinal cord Glycine receptors are inhibited by strychnine. Glutamate and aspartate Widespread in brain and spinal cord Excitatory Drugs that block glutamate or aspartate, such as riluzole, are used to treat amyotrophic lateral sclerosis. These drugs might prevent overexcitation from seizures and neural degeneration. Neuropeptides Endorphins and enkephalins Widely distributed in the CNS and PNS Generally inhibitory Morphine and heroin bind to endorphin and enkephalin receptors on presynaptic neurons and reduce pain by blocking the release of neurotransmitters. Substance P Spinal cord, brain, and sensory neurons associated with pain, GI tract Generally excitatory Substance P is a neurotransmitter involved in pain transmission pathways. Blocking release of substance P by morphine reduces pain. Vasoactive intestinal peptide Gastrointestinal tract Generally excitatory Stimulates secretion, vasodilation, and smooth muscle relaxation (vasodilation, sphincter relaxation). Read more