Synapse

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The Synapse

Questions

76. Gap junctions are characteristically associated with which of the following?

a. Axodendritic synapses

b. Axoaxonic synapses

c. Axosomatic synapses

d. Dendrodendritic synapses

e. Electrical synapses

77. In treating a patient with a movement disorder, you administer a newly developed drug whose functions are mediated at axosomatic synapses. Which of the following statements best characterizes axosomatic synapses?

a. It is referred to as a type I synapse.

b. They have an electrical continuity linking the pre-and postsynaptic cells.

c. They are typically inhibitory.

d. Synaptic transmission is mediated by glutamate.

e. They form the predominant synapse of cortical projections to the neostriatum.

78. Which of the following best describes a basic property of synapses in the central nervous system (CNS)?

a. Synaptic vesicles constitute important features for transmission in both chemical and electrical synapses.

b. A postsynaptic neuron typically receives input from different presynaptic axons that are either excitatory or inhibitory, but it cannot receive inputs from both types.

c. Synaptic delay is approximately the same for both chemical and electrical synapses.

d. Receptors can provide a gating function with respect to a given ion channel.

e. The mechanism of indirect gating of ions normally does not involve the activation of G-proteins.

79. A neurologist selects a drug that has properties similar to that of γ-aminobutyric acid (GABA) for the treatment of temporal lobe epilepsy. This neurotransmitter serves important functions within the CNS. Which of the following accurately characterizes a basic property of this neurotransmitter?

a. GABA is known to have inhibitory as well as excitatory properties.

b. The associated channel is permeable to charged chloride ions.

c. GABA is formed from serine.

d. GABA is associated with the generation of seizure activity.

e. GABA is present mainly in spinal cord.

80. A patient with a history of depression is treated with a novel compound that acts mainly upon N-methyl-D-aspartate (NMDA) receptors. Which of the following best describes a basic property associated with the NMDA receptor?

a. It controls a high-conductance anion channel.

b. The NMDA channel is blocked by the presence of magnesium.

c. NMDA is selective for metabotropic receptors.

d. Insufficient amounts of glutamate, acting through NMDA receptors, may cause neuronal cell death.

e. Current flow is blocked in the presence of glutamate, leading to hyperpolarization of the cell.

81. A noradrenergic drug that binds to β-adrenergic receptors was recommended for use in an acutely depressed patient. Which of the following second-messenger systems are directly activated as a function of the binding of norepinephrine to these receptors?

a. Inositol 1,4,5-triphosphate (IP₃)

b. Adenosine 3′,5′-cyclic monophosphate (cAMP)

c. Diacylglycerol (DAG)

d. Arachidonic acid

e. Prostaglandins

82. A drug designed to hyperpolarize neurons was recommended for use in the treatment of a movement disorder associated with the basal ganglia. Hyperpolarization of a neuron is governed by the actions of which of the following ions?

a. Chloride and sodium

b. Chloride and potassium

c. Potassium and sodium

d. Sodium and calcium

e. Sodium only

83. Which of the following events determines the release of a neurotransmitter from the terminals of a presynaptic neuron?

a. Sodium influx

b. Sodium efflux

c. Potassium influx

d. Potassium efflux

e. Calcium influx

84. A patient was treated with a drug whose basic mechanism involves the activation of second messengers. Which of the following statements is appropriate to second messengers within neurons?

a. They most frequently generate a marked hypersensitization of most types of receptors.

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