Slide Number 1How Do Neurons Communicate and Adapt?Slide Number 3A Chemical MessageA Chemical Message Structure of SynapsesA Chemical Message Structure of SynapsesA Chemical Message Neurotransmission in Four StepsA Chemical Message Neurotransmission in Four StepsA Chemical Message Neurotransmission in Four StepsA Chemical Message Neurotransmission in Four StepsA Chemical Message Neurotransmission in Four StepsSlide Number 12Varieties of NeurotransmittersVarieties of Neurotransmitters Four Criteria for Identifying NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersA Chemical Message Excitatory and Inhibitory MessagesVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Three Classes of NeurotransmittersVarieties of Neurotransmitters Two Classes of ReceptorsVarieties of Neurotransmitters Two Classes of ReceptorsVarieties of Neurotransmitters Two Classes of ReceptorsVarieties of Neurotransmitters Two Classes of ReceptorsSlide Number 29Slide Number 30Neurotransmitter Systems and Behavior Four Activating Systems in the Central Nervous SystemNeurotransmitter Systems and Behavior Neurotransmitter Systems and Behavior Role of Synapses in Three Kinds of Learning and Memory Role of Synapses in Three Kinds of Learning and Memory Role of Synapses in Learning and MemoryHabituation ResponseNeural Basis of HabituationSensitization ResponseNeural Basis of SensitizationNeural Basis of SensitizationLearning as a Change in Synapse NumberLearning as a Change in Synapse NumberSlide Number 44How Do Neurons Communicate and Adapt?How Do Neurons Communicate and Adapt? Charles Scott SherringtonSynaptic delayA Chemical Message • Otto Loewi (1921) • Acetylcholine • Epinephrine (EP, or adrenaline) • Norepinephrine (NE, or noradrenaline)A Chemical Message Structure of Synapses • Synaptic Vesicle • Synaptic Cleft • Chemical Synapse • Presynaptic Membrane • Postsynaptic Membrane • Storage granule• Synaptic Vesicle • Synaptic Cleft • Chemical Synapse • Presynaptic Membrane • Postsynaptic Membrane • Storage granule A Chemical Message Structure of SynapsesA Chemical Message Neurotransmission in Four Steps Step 1: Synthesis and Storage • Synthesized in the Axon Terminal • Synthesized in the Cell BodyA Chemical Message Neurotransmission in Four Steps Step 2: Neurotransmitter Release • calcium (Ca2+) • calmodulinA Chemical Message Neurotransmission in Four Steps Step 3: Receptor-Site Activation • Transmitter-Activated ReceptorsA Chemical Message Neurotransmission in Four Steps Step 3: Receptor-Site Activation • Autoreceptors • Quantum (pl. quanta)A Chemical Message Neurotransmission in Four Steps Step 4: Deactivation of the Neurotransmitter • Diffusion • Degradation • Reuptake • glial cellsFig. 3-8, p. 59Varieties of Neurotransmitters • About 50 different kinds have been identified • Some are inhibitory at one location and excitatory at another • More than one neurotransmitter may be active at a single synapse • No simple one-to-one relationship between a single neurotransmitter and a single behaviorVarieties of Neurotransmitters Four Criteria for Identifying NeurotransmittersVarieties of Neurotransmitters Three Classes of Neurotransmitters 1. Small-molecule transmitters 2. Peptide transmitters 3. Transmitter gasesVarieties of Neurotransmitters Three Classes of Neurotransmitters 1. Small-Molecule Transmitters • Class of quick-acting neurotransmitters • Synthesized from dietary nutrients and packaged ready for use in axon terminalsVarieties of Neurotransmitters Three Classes of Neurotransmitters 1. Small-Molecule Transmitters • Examples: – Acetylcholine (ACh) – Amines: Dopamine (DA), Norepinephrine (NE), Epinephrine (EP), Serotonin (5-HT) – Amino Acids: Glutamate (Glu), Gamma-aminobutyric acid (GABA), Glycine (Gly)Varieties of Neurotransmitters Three Classes of Neurotransmitters 1. Small-Molecule Transmitters • Acetylcholine Synthesis – Choline – Acetate • Breakdown of Acetylcholine – Enzyme: Acetylcholinesterace (AChE) Two important enzymes: • Acetyl coenzyme A • Choline acetyltransferace (ChAT)Varieties of Neurotransmitters Three Classes of Neurotransmitters 1. Small-Molecule Transmitters • Sequential Synthesis of Three AminesVarieties of Neurotransmitters Three Classes of Neurotransmitters 1. Small-Molecule Transmitters • Amino Acid Transmitters – Glutamate: main excitatory transmitter – GABA: main inhibitory transmitterA Chemical Message Excitatory and Inhibitory Messages Type I Synapse Type II SynapseVarieties of Neurotransmitters Three Classes of Neurotransmitters 2. Peptide Transmitters • Neuropeptide – A multifunctional chain of amino acids that act as a neurotransmitter – Synthesized from mRNA on instructions from the cell’s DNA – Do not bind to ion channels; do not have direct effects on the voltage of the postsynaptic membraneVarieties of Neurotransmitters Three Classes of Neurotransmitters 2. Peptide TransmittersVarieties of Neurotransmitters Three Classes of Neurotransmitters 3. Transmitter Gases • Synthesized in cell, as needed • Easily crosses cell membrane • Examples: – Nitric Oxide (NO) – Carbon Monoxide (CO)Varieties of Neurotransmitters Two Classes of Receptors • Ionotropic ReceptorVarieties of Neurotransmitters Two Classes of Receptors • Metabotropic Receptor • G proteinVarieties of Neurotransmitters Two Classes of Receptors • Metabotropic Receptor • G proteinVarieties of Neurotransmitters Two Classes of Receptors • Second Messenger – A chemical that carries a message to initiate a biochemical processNeurotransmitter Synapse 3D AnimationNeurotransmitter Systems and Behavior Four Activating Systems in the Central Nervous System • Activating System – Neural pathways that coordinate brain activity through a single neurotransmitter – Cell bodies are located in a nucleus in the brainstem and their axons are distributed through a wide region of the brain – Four Systems • Cholinergic,