Indicate whether the following statements most accurately refer to ionotropic ne
ID: 3478084 • Letter: I
Question
Indicate whether the following statements most accurately refer to ionotropic neurotransmitter receptors, metabotropic neurotransmitter receptors, neither or both:
A. Have intrinsic ion channels CHOOSE 1
B. Can link indirectly to potassium channels CHOOSE 1
C. Mediate fast synaptic transmission CHOOSE 1
D. Neuromodulators CHOOSE 1
E. Found on postsynaptic neurons CHOOSE 1
F. Most serotonin receptors CHOOSE 1
G. An example is a glutamate receptor CHOOSE 1
H. Use heterotrimeric G-proteins to produce their responses. CHOOSE 1
I. Are always inhibitory CHOOSE 1
J. Are found in glutamatergic neurons CHOOSE 1
Explanation / Answer
Ionotrophic neurotransmitter receptors are transmembrane receptors that control the channels, which allow small ions to travel in and out of the cells. A small neurotransmitter has to bind to the receptor to open the channels.
Metabotrophic neurotransmitter receptors are not associated with any channels. Their action is based on binding of the neurotransmitter to the receptor activating small G proteins that are associated with the receptor.
A. The receptors that have intrinsic ions channels will be ionotrophic neurotransmitter receptors, as they are associated with ion channels. These ions channels open and close depending on association with the ligand. Example is ligand gated ion channels.
B. Metabotrophic neurotransmitter receptors can link indirectly to ion channels on the plasma membrane though signal transduction pathways. Hence, these receptors are linked indirectly to potassium channels. Example is the G protein linked potassium channel (IKACh).
C. Ionotrophic neurotransmitter receptors mediate fast synaptic transmission, as ligand binding will immediately activate the receptor to open the ion channels. It does not depend on secondary messengers to activate the channels for synaptic transmission. Example is glutamate neurotransmission in CNS.
D. Neuromodulators interact with Metabotrophic neurotransmitter receptors, so that they can modulate the neuron slowly over a period of time. Their interaction activates G receptors; Gs, Gi and Gq. Example are dopamine and noradrenaline neuromodulators.