A 47-year-old woman experienced a migraine headache that wasnot relieved by her current pain medications. The doctor optedto prescribe a drug that targets receptors or ion channels withinthe pain pathway. Which of the following drugs is used to treatmigraines and which receptor or ion channel does it affect?A. Topiramate and voltage-gated Na+ channelB. Ziconotide and voltage-gated N-type Ca2+ channelC. Valproate and TRPV1 receptorsD. Carbamazepine and voltage-gated Na+ channelsE. Gabapentin and Nav1.8

Which one of the following is a ligand-gated ion channel?a.Muscarinic receptorsb.Thyroxine receptorsc.Nicotinic receptorsd.Insulin receptors

Which of the following is NOT a ligand-gated ion channel?Group of answer choicesa nicotinic acetylcholine receptora GABA-A receptora glycine receptora noradrenaline receptoran AMPA receptor

Passage 5 (Questions 23 - 27)A key modulator of action potential firing is the hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channel. These channels are permeable to both Na+ and K+. The HCN current, Ih, is found in neurons under hyperpolarization of the cell membrane and is proportional to the frequency of firing of action potentials.Neurologists wished to determine if a new drug, Compound X (Figure 1), is able to block Ih and reduce neuropathic stimulation, providing significant analgesic effects to those with pain.Figure 1 Structure of lidocaine (left) and Compound X (right), a potential ion channel blockerCompound X’s effect on neuronal firing was first compared to lidocaine, a known sodium channel inhibitor. Ganglion cells were treated with 3 different concentrations of Compound X. Sodium current was isolated and then recorded using patch-clamping. Figure 2 shows the results of these recordings.Figure 2 Na+ current in ganglion neurons treated with Compound X; traces were recorded in the presence and absence (control) of different concentrations of Compound XTo test if Compound X also blocked HCN channel currents, the drug’s effect on HCN currents in ganglion cell neurons was recorded. The HCN channel whole-cell current in neurons was induced by delivering a membrane potential step from a holding potential of -60 mV, to -140 mV for 700 ms, and then back to -70 mV. Solutions of 5 mL each were prepared with differing amounts of Compound X. Figure 3 shows the effect of Compound X concentration on HCN currents in neurons.Figure 3 Inhibition of HCN currents by addition of Compound X Question 27What alteration to an HCN channel will favor the transport of Na+ over K+? A.Increasing the diameter of the channel by adding amino acidsB.Decreasing the diameter of the channel by removing amino acidsC.Replacing the serine groups in the channel with alanineD.Replacing the alanine groups in the channel with serine

Which of the following transmitter combinations all have at least one ionotropic receptor (i: ligand gated ion channel)?Group of answer choicesGABA, 5-hydroxytryptamine and glutamateAcetylcholine, dopamine and noradrenalineGABA, glutamate and enkephalin5-Hydroxytryptamine, GABA and dopaminenoradrenaline, acetylcholine and GABA

Which ligand-gated ion channel is regulated primarily by an intracellular signal?Select one:Select the correct definitionGlutamate receptorThe potassium-activated calcium channelThe glutamate receptorThe cAMP- and cGMP-gated ion channelsThe acid-sensing ion channels