Neurotransmission and Receptors Quiz
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Questions and Answers

What type of binding occurs when a drug binds noncompetitively to a receptor's alternative site?

  • Competitive binding
  • Presynaptic binding
  • Agonistic binding
  • Noncompetitive binding (correct)

    • Which neurotransmitter is primarily responsible for excitatory effects in the CNS?

  • Gamma-aminobutyric acid (GABA)
  • Glutamate (correct)
  • Dopamine
  • Serotonin

    • Which enzyme is responsible for the synthesis of GABA from its precursor?

  • Glutaminase
  • Glutamic acid decarboxylase (GAD) (correct)
  • Amino acid transferase
  • Glutamine synthesase

    • What is the role of an indirect antagonist in neurotransmission?

    <p>Blocks the receptor's ion channel from opening</p> Signup and view all the answers

    Which of the following statements about glutamate receptors is true?

    <p>They include ionotropic receptors like NMDA and AMPA.</p> Signup and view all the answers

    What characterizes the decremental nature of PSPs?

    <p>They decrease in amplitude as they travel towards the axon initial segment.</p> Signup and view all the answers

    Which statement distinguishes an action potential from a postsynaptic potential?

    <p>Action potentials are all-or-none and not decremental.</p> Signup and view all the answers

    What does spatial summation involve?

    <p>Summing simultaneous PSPs from different physical locations.</p> Signup and view all the answers

    How does reuptake terminate postsynaptic potentials?

    <p>By transporting neurotransmitter molecules back into the presynaptic neuron.</p> Signup and view all the answers

    What role do axoaxonic synapses play in neural integration?

    <p>They decrease neurotransmitter release through presynaptic inhibition.</p> Signup and view all the answers

    Which type of synapse occurs between dendrites?

    <p>Dendrodendritic synapse.</p> Signup and view all the answers

    What terminates postsynaptic potentials for neurotransmitters like acetylcholine?

    <p>Enzymatic deactivation.</p> Signup and view all the answers

    What is an example of presynaptic modulation?

    <p>Decreasing the amount of neurotransmitter released by terminals.</p> Signup and view all the answers

    Which of the following describes temporal summation?

    <p>PSPs produced in rapid succession summing to form a greater signal.</p> Signup and view all the answers

    What process allows neurotransmitters to be released into the synaptic cleft?

    <p>Fusion of the vesicle with the presynaptic membrane</p> Signup and view all the answers

    Which ion's influx is critical for the release of neurotransmitters during neurotransmission?

    <p>Ca2+ ions</p> Signup and view all the answers

    What characterizes large synaptic vesicles in the presynaptic terminal?

    <p>They contain neuropeptides and are produced in the soma.</p> Signup and view all the answers

    What is the primary function of the release zone in neurotransmission?

    <p>To release neurotransmitters into the synaptic cleft</p> Signup and view all the answers

    What is the consequence if neurons are in a solution without Ca2+ ions?

    <p>Neurotransmitter release is inhibited.</p> Signup and view all the answers

    What does coexistence/co-localization in neurons refer to?

    <p>The phenomenon where a neuron contains more than one type of neurotransmitter</p> Signup and view all the answers

    What describes the role of voltage-dependent calcium channels during neurotransmission?

    <p>They cause the release of neurotransmitters into the synaptic cleft.</p> Signup and view all the answers

    Which of the following statements is true regarding the role of L-Dopa in the treatment of Parkinson's disease?

    <p>L-Dopa acts as a precursor to increase dopamine synthesis.</p> Signup and view all the answers

    What role do vesicle transporters play in neurotransmitter release?

    <p>They fill synaptic vesicles with neurotransmitters before release.</p> Signup and view all the answers

    How do direct antagonists function at the postsynaptic receptors?

    <p>They occupy the receptor sites and prevent activation.</p> Signup and view all the answers

    Which of the following describes an agonist's effect on neurotransmission?

    <p>It mimics neurotransmitters and enhances their action.</p> Signup and view all the answers

    In what way do antagonists interact with enzymes involved in neurotransmitter synthesis?

    <p>They deactivate the enzymes, preventing neurotransmitter production.</p> Signup and view all the answers

    What is the primary function of drugs that block vesicle transporters?

    <p>To keep vesicles empty and inhibit neurotransmitter release.</p> Signup and view all the answers

    What is the main effect of Botox on neurotransmitter activity?

    <p>It prevents the release of acetylcholine at the neuromuscular junction.</p> Signup and view all the answers

    Which of the following best describes a precursor drug?

    <p>A drug that increases neurotransmitter production through synthesis.</p> Signup and view all the answers

    What type of effect does a direct agonist have on a neurotransmitter's receptor?

    <p>It activates the receptor in a manner similar to the neurotransmitter.</p> Signup and view all the answers

    What is the primary function of dendrodendritic synapses?

    <p>To facilitate electrical communication between neurons.</p> Signup and view all the answers

    Which statement about neuromodulators is accurate?

    <p>They can modulate the activity of many neurons over a broader area.</p> Signup and view all the answers

    How do hormones differ from neuromodulators?

    <p>Hormones act exclusively on target cells that possess specialized receptors.</p> Signup and view all the answers

    What defines a drug in the context of psychopharmacology?

    <p>A foreign chemical that alters physiological functions in low doses.</p> Signup and view all the answers

    Which type of drug facilitates neurotransmitter action?

    <p>Agonists that enhance the effects of neurotransmitters.</p> Signup and view all the answers

    What characterizes electrical synapses formed by gap junctions?

    <p>They allow for faster communication between neurons.</p> Signup and view all the answers

    What is the relationship between hormones and target cells?

    <p>Target cells possess specific receptors for corresponding hormones.</p> Signup and view all the answers

    What is one uncertainty regarding gap junctions?

    <p>Their specific function is completely unknown.</p> Signup and view all the answers

    What best describes the nature of psychopharmacology?

    <p>It examines how drugs impact both the nervous system and behavior.</p> Signup and view all the answers

    Which of the following compounds is typically not considered a neuromodulator?

    <p>Classic neurotransmitters acting at synaptic clefts.</p> Signup and view all the answers

    Study Notes

    Neurotransmission

    • Neurotransmission is a process where neurons communicate with each other using various chemical messengers called neurotransmitters.
    • Synaptic vesicles contain neurotransmitters. Small vesicles contain neurotransmitters, while large vesicles contain neuropeptides.
    • Release of neurotransmitters involves docking, release zone, and voltage-dependent calcium channels.
    • Action potentials cause calcium influx, which triggers fusion pore formation, eventually releasing the neurotransmitter into the synapse.
    • There are 3 pools of synaptic vesicles: release-ready, recycling, and reserve.
    • Kiss-and-run and merge-and-recycle are ways vesicles release neurotransmitter.
    • Bulk endocytosis recycles membrane material to form new synaptic vesicles.

    Types of Receptors

    • Receptors are proteins on the postsynaptic membrane that bind to neurotransmitters.
    • Receptors can be ionotropic or metabotropic, distinguished by how they influence ion channels.
    • Ionotropic receptors are directly coupled to ion channels; binding opens channels immediately.
    • Metabotropic receptors are indirectly coupled to ion channels, involving a G protein and causing slower, longer-lasting effects.

    Activation of Receptors

    • Neurotransmitters bind to specific receptors. Binding is key-lock mechanism; crucial for specificity.
    • Binding to the receptor opens neurotransmitter-dependent ion channels.
    • This directly changes the local membrane potential.
    • Receptors are important for direct and indirect neurotransmission.

    Neurotransmission Methods

    • Direct neurotransmission involves immediate opening of ion channels.
    • Indirect neurotransmission uses a second-messenger system.

    Autoreceptors

    • Autoreceptors are receptors on the presynaptic neuron that respond to neurotransmitters that the neuron itself releases.
    • They regulate internal processes, such as synthesis and release of the neurotransmitter.

    Postsynaptic Potentials

    • Postsynaptic potentials (PSPs) are graded potentials, and their amplitude depends on the intensity of the signal.
    • PSPs are decremental (decrease in amplitude as they travel).
    • Spatial summation is the incorporation of several simultaneous PSPs from various locations on the postsynaptic neuron, considering the excitatory and inhibitory impact.
    • Temporal summation is the interplay of PSPs that occur rapidly in sequence.

    Synaptic Termination

    • Termination of PSPs involves reuptake or enzymatic deactivation from the synapse.
    • Reuptake involves special transporters taking the neurotransmitters from the synaptic cleft back into the presynaptic neuron's cytoplasm.
    • Enzymatic deactivation involves an enzyme destroying the neurotransmitter molecule.

    Neurotransmitter Classifications

    • Amino acids (e.g., glutamate, GABA)
    • Monoamines (e.g., dopamine, norepinephrine, serotonin)
    • Neuropeptides (e.g., pituitary, hypothalamic, brain-gut, opioid peptides)
    • Gas neurotransmitters (e.g., nitric oxide)
    • Lipids (e.g., endocannabinoids).

    Other Chemical Communications

    • Neuromodulators are more diffused messengers influencing several neurons.
    • Hormones are released into the bloodstream influencing many cells, including neurons.

    Drug Effects on Neurotransmission

    • Drugs can be agonists or antagonists, influencing neurotransmission.
    • Agonists enhance the effects of neurotransmitters, whereas antagonists hinder them.
    • Drugs impact neurotransmission at different stages: synthesis, storage, release, receptors, reuptake, and breakdown.

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    Related Documents

    Task 3 - Neurotransmission PDF

    Description

    Test your knowledge on neurotransmission processes and receptor types. This quiz covers the mechanisms of neurotransmitter release, synaptic vesicle pools, and the different receptor classifications. Enhance your understanding of how neurons communicate.

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