lecture_Ch04_3[1]

lecture_Ch04_3[1] - Drugs and Behavior Drugs Homeostatic...

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Unformatted text preview: Drugs and Behavior Drugs Homeostatic Systems and Drugs – part III PSY 291 Pools of vesicles and their recycling method Synapses Synapses Excitatory synapse—initiates an impulse in initiates the receiving neuron when stimulated, causing release of neurotransmitters or increasing activity in target cell increasing Inhibitory synapse—diminishes likelihood diminishes of an impulse in the receiving neuron or reduces the activity in other target cells reduces Communication Between Neurons Communication Neural Integration – process by which inhibitory Neural and excitatory postsynaptic potentials summate and control the rate of firing of a neuron. and Transfer of messages by neurons Transfer Neurotransmitter – an endogenous chemical released by neuron at a synapse for the purpose of relying information to the target cell via receptors. cell Activation of receptors causes a change in the Activation activity of the target cell; the target cells can activity be other neurons or cells that make up organs, muscles, or glands. muscles, Postsynaptic Receptors Postsynaptic Molecules of neurotransmitter (NT) bind to Molecules receptors located on the postsynaptic membrane. membrane. Receptor activation opens postsynaptic ion Receptor channels. channels. Ions flow through the membrane, producing Ions either depolarization or hyperpolarization. either The resulting postsynaptic potential (PSP) The depends on which ion channel is opened. depends Ionic Movement During Postsynaptic Potentials Ionic Receptors only interact with molecules that Receptors have specific configurations have Neurotransmitters can interact with 2 or Neurotransmitters more receptors. more NT NT Receptor A Receptor B Phospholipid bilayer D D Receptor A Receptor B Phospholipid bilayer D D Receptor A Receptor B Phospholipid bilayer What happens to the transmitter after release? after Receptor Interaction (excite or inhibit) Post-synaptic process Inactivation / Degradation Inactivation Enzymes in cleft Re-Uptake Pre-synaptic process Communication Between Neurons Communication Termination of Postsynaptic Potentials Reuptake – reentry of neurotransmitter just released Reuptake by a terminal button back through its membrane (transporter molecules), thus terminating the postsynaptic potential. postsynaptic Enzymatic Deactivation – destruction of a Enzymatic neurotransmitter by an enzyme after its release (ACh). neurotransmitter Acetylcholine = choline + acetyl CoA (precursors) Typically broken down in synaptic cleft by Acetylcholinesterase Neurotransmitters Neurons are distinguished by the type of neurotransmitter Neurons they release. they Neurotransmitters represent a wide variety of chemical Neurotransmitters substances and functions. substances Many drugs affect the activity of neurotransmitters by Many altering their synthesis, storage, release, post-synaptic action, or deactivation. Neurotransmitters frequently altered by drugs of abuse: Acetylcholine Catecholamines Serotonin GABA Endorphins Anandamide Neurotransmitter Type of Effect CNS Changes Affecting Drugs of Abuse Catecholamines (Dopamine, Norepinephrine, Epinephrine) inhibitoryexcitatory euphoria, agitation paranoia amphetamines, cocaine GABA inhibitory sedation, relaxation drowsiness, depression alcohol, valium-type barbiturates Serotonin inhibitory sleep, relaxation sedation LSD Acetylcholine excitatoryinhibitory mild euphoria excitation, insomnia nicotine Endorphins inhibitory mild euphoria, block pain, slow respiration narcotics Anandamide inhibitory relaxation, increase sense of well-being THC (marijuana-like) Drug Effects on Neurotransmitters Drug Synthesis Drugs may exert their agonistic or antagonistic Drugs effects by influencing the production of neurotransmitters. neurotransmitters. Drug Effects on Neurotransmitters Drug Synthesis Storage Drugs may exert their agonistic or antagonistic Drugs effects by influencing the storage of neurotransmitters. neurotransmitters. Drug Effects on Neurotransmitters Drug Synthesis Storage Release Drugs may exert their agonistic or antagonistic Drugs effects by influencing the release of neurotransmitters. neurotransmitters. Drug Effects on Neurotransmitters Drug Synthesis Storage Release Post-synaptic action Drugs may exert their agonistic or antagonistic Drugs effects by influencing receptors. effects Drug Effects on Neurotransmitters Drug Synthesis Storage Release Post-synaptic action Deactivation/re-uptake Drugs may exert their agonistic or antagonistic Drugs effects by influencing the reuptake or destruction of neurotransmitters. neurotransmitters. Communication Between Neurons Communication Autoreceptors – specialized receptor molecules located on a neuron that respond to the neurotransmitter released by that neuron. neurotransmitter Control the production and release of Control neurotransmitter. neurotransmitter. Drug Effects on Neurotransmitters Drug Synthesis Storage Release Post-synaptic action Deactivation/re-uptake Autoreceptors Drugs may exert their agonistic or antagonistic Drugs effects by influencing autoreceptors. effects Introduction to the Endocrine System Introduction The endocrine system consists of secreting glands glands Examples adrenal adrenal thyroid pituitary gonads Endocrine System Endocrine These glands produce hormones These hormones Adrenaline (adrenal medulla) = epinephrine Steroids (adrenal cortex) = corticosteroids Insulin (pancreas) Sex hormones - testosterone, estrogen, Sex progesterone- (gonads) progesterone- These substances are information These transferring molecules, like NTs transferring Neurotransmitter – an endogenous chemical released by neuron at a synapse for the purpose of relying information to the target cell via receptors. information Hormones are secreted by a gland into the bloodstream and carried by the blood to all the organs and tissues of the body. organs Hormones affect selected tissues that are designed to receive the information. receive Hormones may be highly selective or very general with regard to the cells or organs they influence. Hormones vs. Neurotransmitters 1. slower onset, 2. longer duration of action, 3. more generalized target 3. Specific Hormones: Androgens Specific Male sex hormones (testosterone) Influence sex-related body features Influence Muscular development Hair growth Voice changes Fat distribution Anabolic steroids Anabolic Anabolic steroids (natural androgens and Anabolic syntetic hormones) Structurally related to testosterone Produce growth of muscle mass Increase body weight Increase Also influence emotional states Probably cross blood-brain barrier and affect Probably limbic system limbic Anabolic steroids Anabolic (physical effects) Desired anabolic effects (converting Desired nutrients into tissue mass) nutrients Unwanted side effects: Abuse potential Abuse Changes in liver, reproductive system, skin, Changes cardiovascular system, headaches, insomnia cardiovascular Anabolic steroids Anabolic (psychological effects) Increased aggressiveness Increased Uncontrollable anger Anxiety Paranoia ...
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