{"id":179,"date":"2023-02-17T22:37:13","date_gmt":"2023-02-17T22:37:13","guid":{"rendered":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/neurotransmitters-and-drugs\/"},"modified":"2025-11-04T20:40:52","modified_gmt":"2025-11-04T20:40:52","slug":"neurotransmitters-and-drugs","status":"publish","type":"chapter","link":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/neurotransmitters-and-drugs\/","title":{"raw":"The Nervous System: Learn It 4\u2014Neurotransmitters","rendered":"The Nervous System: Learn It 4\u2014Neurotransmitters"},"content":{"raw":"

Understanding Neurotransmitters<\/h2>\r\n

Now that you know how a neuron sends an electrical signal, let\u2019s zoom out to see how billions of neurons<\/strong> work together.
\r\nEach neuron communicates using neurotransmitters<\/strong>\u2014tiny chemical messengers that carry signals across the gaps (synapses) between neurons. These chemicals allow your brain to think, move, remember, and feel.<\/p>\r\n

Think of neurotransmitters as different kinds of messages<\/strong> traveling along an enormous web of communication lines. Some messages say \u201cspeed up\u201d or \u201cpay attention,\" while others say \u201cslow down\u201d or \u201ceverything\u2019s fine.\u201d The balance among these signals shapes how your brain and body function moment to moment.<\/p>\r\n

Recall that psychologists who emphasize a\u00a0biological perspective<\/strong>\u00a0focus on the physiological causes of behavior\u2014they would assert that psychological disorders like depression and schizophrenia are associated with imbalances in one or more neurotransmitter systems.
\r\n
\r\nAccording to this perspective,\u00a0psychotropic medications<\/strong>\u00a0can help improve the symptoms associated with these disorders. Psychotropic medications are drugs that treat psychiatric symptoms by restoring neurotransmitter balance.<\/section>\r\n

Psychoactive drugs can act as agonists or antagonists for a given neurotransmitter system.<\/p>\r\n

\r\n

agonists and antagonists<\/h3>\r\n

Drugs can either mimic<\/strong> or block<\/strong> neurotransmitters:<\/p>\r\n

    \r\n\t
  • \r\n

    Agonists<\/strong> imitate a neurotransmitter by binding to its receptor and strengthening<\/strong> the signal.<\/p>\r\n<\/li>\r\n\t

  • \r\n

    Antagonists<\/strong> block a receptor and prevent<\/strong> the neurotransmitter from activating it.<\/p>\r\n<\/li>\r\n<\/ul>\r\n

    These effects can help correct certain imbalances:<\/p>\r\n

      \r\n\t
    • \r\n

      Parkinson\u2019s disease<\/strong> involves low dopamine levels<\/em>, so doctors may prescribe dopamine agonists<\/strong> that mimic dopamine and restore movement.<\/p>\r\n<\/li>\r\n\t

    • \r\n

      LSD<\/strong> acts as a serotonin agonist<\/strong>, producing powerful perceptual effects.<\/p>\r\n<\/li>\r\n\t

    • \r\n

      Antipsychotic drugs<\/strong> work as dopamine antagonists<\/strong>, reducing excessive dopamine activity linked to schizophrenia.<\/p>\r\n<\/li>\r\n<\/ul>\r\n<\/section>\r\n

      \r\n

      neurotransmitter activity<\/h3>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
      Table 1. Major Neurotransmitters and How They Affect Behavior<\/caption>\r\n
      Neurotransmitter<\/th>\r\nInvolved in<\/th>\r\nPotential Effect on Behavior<\/th>\r\nConnection<\/th>\r\n<\/tr>\r\n<\/thead>\r\n
      Acetylcholine<\/td>\r\nMuscle action, memory<\/td>\r\nIncreased arousal, enhanced cognition<\/td>\r\nCrucial for muscle movement\u2014paralyzed muscles in botulism are due to blocked ACh; nicotine acts as an acetylcholine agonist.<\/td>\r\n<\/tr>\r\n
      Beta-endorphin<\/td>\r\nPain, pleasure<\/td>\r\nDecreased anxiety, decreased tension<\/td>\r\nNatural painkiller released during exercise (\u201crunner\u2019s high\u201d) or laughter; mimicked by opioid drugs like morphine.<\/td>\r\n<\/tr>\r\n
      Dopamine<\/td>\r\nMood, sleep, learning<\/td>\r\nIncreased pleasure, suppressed appetite<\/td>\r\nCentral to reward and motivation; linked to the brain\u2019s \u201cfeel-good\u201d pathway activated by food, music, or social praise; low levels associated with Parkinson\u2019s disease.<\/td>\r\n<\/tr>\r\n
      Gamma-aminobutyric acid (GABA)<\/td>\r\nBrain function, sleep<\/td>\r\nDecreased anxiety, decreased tension<\/td>\r\nMajor calming neurotransmitter; anti-anxiety medications (benzodiazepines) enhance GABA\u2019s effects to quiet overactive neurons.<\/td>\r\n<\/tr>\r\n
      Glutamate<\/td>\r\nMemory, learning<\/td>\r\nIncreased learning, enhanced memory<\/td>\r\nThe brain\u2019s main excitatory neurotransmitter; involved in forming memories\u2014excess glutamate can cause cell damage after stroke.<\/td>\r\n<\/tr>\r\n
      Norepinephrine<\/td>\r\nHeart, intestines, alertness<\/td>\r\nIncreased arousal, suppressed appetite<\/td>\r\nHeightens alertness and prepares the body for \u201cfight or flight\u201d; levels spike during stress or danger.<\/td>\r\n<\/tr>\r\n
      Serotonin<\/td>\r\nMood, sleep<\/td>\r\nModulated mood, suppressed appetite<\/td>\r\nOften called the \u201cfeel-good\u201d neurotransmitter; antidepressants (SSRIs) increase serotonin availability to improve mood.<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/section>\r\n

      Psychotropic drugs are not instant solutions for people suffering from psychological disorders. Often, an individual must take a drug for several weeks before seeing improvement, and many psychoactive drugs have significant negative side effects. Furthermore, individuals vary dramatically in how they respond to a drug. To improve chances for success, it is not uncommon for people receiving pharmacotherapy to undergo psychological and\/or behavioral therapies as well. Some research suggests that combining drug therapy with other forms of therapy tends to be more effective than any one treatment alone (March et al., 2007).<\/p>\r\n

      [ohm2_question height=\"600\"]3941[\/ohm2_question]<\/section>\r\n
      \r\n
      \r\n

      Mapping the Brain\u2019s Chemical Messengers<\/h3>\r\n

      For decades, scientists could only guess where different neurotransmitters were most active in the brain. Now, positron emission tomography (PET) imaging techniques have made it possible to map those chemical systems in living humans with increasing detail.[footnote]Hansen, J. Y., Markello, R. D., Vogel, J. W., Seidlitz, J., Bzdok, D., & Misic, B. (2022). Mapping neurotransmitter systems to the structural and functional organization of the human neocortex. Nature Neuroscience, 25(11), 1569\u20131581. https:\/\/doi.org\/10.1038\/s41593-022-01186-3[\/footnote]<\/p>\r\n

      \r\n[caption id=\"attachment_7075\" align=\"aligncenter\" width=\"893\"]\"PET Figure 1. Each column shows a major neurotransmitter system (serotonin, dopamine, acetylcholine, etc.), while each row shows a specific receptor or transporter type within that system. The darker purple\/blue colors represent a lower receptor density, while lighter yellow\/red colors mean a higher receptor density.[\/caption]\r\n<\/div>\r\n

      What Do the Labels Mean?<\/h4>\r\n
        \r\n\t
      • 5-HT stands for serotonin (5-hydroxytryptamine<\/em>).\r\n\r\n
          \r\n\t
        • 5-HT\u2082A receptors influence perception and consciousness and are activated by psychedelics.<\/li>\r\n\t
        • 5-HTT means serotonin transporter\u2014the target of many SSRI antidepressants.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t
        • D\u2081, D\u2082, DAT = dopamine receptors and transporter (linked to motivation and reward).<\/li>\r\n\t
        • GABA\u2090\/BZ = receptors for GABA, the brain\u2019s major calming neurotransmitter.<\/li>\r\n\t
        • NMDA, mGluR\u2085 = glutamate receptors (involved in learning and memory).<\/li>\r\n<\/ul>\r\n

          This brain \u201cchemistry map\u201d helps visually connect the relationship between molecules, brain networks, and behavior.\u00a0 It shows where neurotransmitters act and how they interact, helping researchers:<\/p>\r\n

            \r\n\t
          • Understand why specific drugs (like SSRIs or antipsychotics) affect some regions more than others.<\/li>\r\n\t
          • See how disorders such as depression, addiction, or schizophrenia involve imbalances in multiple systems, not just one chemical.<\/li>\r\n\t
          • Develop more targeted and personalized treatments for mental health conditions.<\/li>\r\n<\/ul>\r\n<\/section>\r\n
            \r\n
              \r\n\t
            • Which neurotransmitter systems from the table above appear to have the broadest distribution across the brain in Figure 1?<\/li>\r\n<\/ul>\r\n<\/section>\r\n<\/section>","rendered":"

              Understanding Neurotransmitters<\/h2>\n

              Now that you know how a neuron sends an electrical signal, let\u2019s zoom out to see how billions of neurons<\/strong> work together.

              \nEach neuron communicates using neurotransmitters<\/strong>\u2014tiny chemical messengers that carry signals across the gaps (synapses) between neurons. These chemicals allow your brain to think, move, remember, and feel.<\/p>\n

              Think of neurotransmitters as different kinds of messages<\/strong> traveling along an enormous web of communication lines. Some messages say \u201cspeed up\u201d or \u201cpay attention,” while others say \u201cslow down\u201d or \u201ceverything\u2019s fine.\u201d The balance among these signals shapes how your brain and body function moment to moment.<\/p>\n

              Recall that psychologists who emphasize a\u00a0biological perspective<\/strong>\u00a0focus on the physiological causes of behavior\u2014they would assert that psychological disorders like depression and schizophrenia are associated with imbalances in one or more neurotransmitter systems. <\/p>\n

              According to this perspective,\u00a0psychotropic medications<\/strong>\u00a0can help improve the symptoms associated with these disorders. Psychotropic medications are drugs that treat psychiatric symptoms by restoring neurotransmitter balance.<\/section>\n

              Psychoactive drugs can act as agonists or antagonists for a given neurotransmitter system.<\/p>\n

              \n

              agonists and antagonists<\/h3>\n

              Drugs can either mimic<\/strong> or block<\/strong> neurotransmitters:<\/p>\n

                \n
              • \n

                Agonists<\/strong> imitate a neurotransmitter by binding to its receptor and strengthening<\/strong> the signal.<\/p>\n<\/li>\n

              • \n

                Antagonists<\/strong> block a receptor and prevent<\/strong> the neurotransmitter from activating it.<\/p>\n<\/li>\n<\/ul>\n

                These effects can help correct certain imbalances:<\/p>\n

                  \n
                • \n

                  Parkinson\u2019s disease<\/strong> involves low dopamine levels<\/em>, so doctors may prescribe dopamine agonists<\/strong> that mimic dopamine and restore movement.<\/p>\n<\/li>\n

                • \n

                  LSD<\/strong> acts as a serotonin agonist<\/strong>, producing powerful perceptual effects.<\/p>\n<\/li>\n

                • \n

                  Antipsychotic drugs<\/strong> work as dopamine antagonists<\/strong>, reducing excessive dopamine activity linked to schizophrenia.<\/p>\n<\/li>\n<\/ul>\n<\/section>\n

                  \n

                  neurotransmitter activity<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n
                  Table 1. Major Neurotransmitters and How They Affect Behavior<\/caption>\n
                  Neurotransmitter<\/th>\nInvolved in<\/th>\nPotential Effect on Behavior<\/th>\nConnection<\/th>\n<\/tr>\n<\/thead>\n
                  Acetylcholine<\/td>\nMuscle action, memory<\/td>\nIncreased arousal, enhanced cognition<\/td>\nCrucial for muscle movement\u2014paralyzed muscles in botulism are due to blocked ACh; nicotine acts as an acetylcholine agonist.<\/td>\n<\/tr>\n
                  Beta-endorphin<\/td>\nPain, pleasure<\/td>\nDecreased anxiety, decreased tension<\/td>\nNatural painkiller released during exercise (\u201crunner\u2019s high\u201d) or laughter; mimicked by opioid drugs like morphine.<\/td>\n<\/tr>\n
                  Dopamine<\/td>\nMood, sleep, learning<\/td>\nIncreased pleasure, suppressed appetite<\/td>\nCentral to reward and motivation; linked to the brain\u2019s \u201cfeel-good\u201d pathway activated by food, music, or social praise; low levels associated with Parkinson\u2019s disease.<\/td>\n<\/tr>\n
                  Gamma-aminobutyric acid (GABA)<\/td>\nBrain function, sleep<\/td>\nDecreased anxiety, decreased tension<\/td>\nMajor calming neurotransmitter; anti-anxiety medications (benzodiazepines) enhance GABA\u2019s effects to quiet overactive neurons.<\/td>\n<\/tr>\n
                  Glutamate<\/td>\nMemory, learning<\/td>\nIncreased learning, enhanced memory<\/td>\nThe brain\u2019s main excitatory neurotransmitter; involved in forming memories\u2014excess glutamate can cause cell damage after stroke.<\/td>\n<\/tr>\n
                  Norepinephrine<\/td>\nHeart, intestines, alertness<\/td>\nIncreased arousal, suppressed appetite<\/td>\nHeightens alertness and prepares the body for \u201cfight or flight\u201d; levels spike during stress or danger.<\/td>\n<\/tr>\n
                  Serotonin<\/td>\nMood, sleep<\/td>\nModulated mood, suppressed appetite<\/td>\nOften called the \u201cfeel-good\u201d neurotransmitter; antidepressants (SSRIs) increase serotonin availability to improve mood.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/section>\n

                  Psychotropic drugs are not instant solutions for people suffering from psychological disorders. Often, an individual must take a drug for several weeks before seeing improvement, and many psychoactive drugs have significant negative side effects. Furthermore, individuals vary dramatically in how they respond to a drug. To improve chances for success, it is not uncommon for people receiving pharmacotherapy to undergo psychological and\/or behavioral therapies as well. Some research suggests that combining drug therapy with other forms of therapy tends to be more effective than any one treatment alone (March et al., 2007).<\/p>\n