<prompt> NN Nicotinic acetylcholine receptors are present onMyocardiumMotor endplatespresynaptic glutamate-secreting axon terminalsNeuromuscular junction  <response>: 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: Ganongs Review of Medical Physiology 26th edition 