This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
NN Nicotinic acetylcholine receptors are present on 
Select and explain. 
A. Myocardium, B. Motor endplates, C. presynaptic glutamate-secreting axon terminals, D. Neuromuscular junction
C: presynaptic glutamate-secreting axon terminals
Answer: C: presynaptic glutamate-secreting axon terminals 
Explanation: Nicotinic receptors are subdivided into those found at the; neuromuscular junction (NM) CNS and autonomic ganglia (NN) The NN receptors are comprised of only a and b subunits. Each a subunit has a binding site for acetylcholine, and binding of an acetylcholine molecule to each of them induces a conformational change in the protein so that the channel opens. NN receptors in the brain are located presynaptically on glutamate-secreting axon terminals Ref: Ganong's Review of Medical Physiology 26th edition